Overview
The STC-88 is different from other hammers: The design and construction
tips on this page were meant for the Striker STC-88 hammer. Striker Tool Company has
worked with the manufacturer to greatly improve the overall design of the C41-
style hammers, including a wider base,
heavier anvil block, and a heavier stronger frame. The STC-88 is over 650 pounds (34%) heavier than other
hammers in the same size class, and physical dimensions are very different from
hammers made by other manufacturers. Owners of other hammer brands will need to
modify the
plans and designs described here, to fit their hammers.
Hammer setup is not for beginners. Air
hammers are partially disassembled for shipping. The owner must be ready and
able to build up the hammer and motor on a work stand, and
install electrical service properly to the hammer. If the owner of a new hammer
does not posses the skills of a master mechanic, and welder, and have basic knowledge
of industrial electrical motors and starters, then their hammer will not operate
correctly. Get help! This hammer runs trouble-free and with minimal maintenance
if installed correctly! The STC-88 hammer is very heavy. At 2600 pounds (approx. 1200 kg), the owner
will need access to appropriate forklift, loader, or crane to lift and move the
hammer. The motor weighs roughly 200 pounds and is difficult and dangerous for
one person to move alone.
Designs presented here are my own.
The hammer work stand shown here includes accommodation for lifting by 5,000
lbs. fork truck. The hammer mounting bolts are fully accessible from outside of
the work stand. Thickness of the upper deck plate (hammer mounting surface) was
increased to 1" to add more support under the hammer. And to create a heavier and more robust box frame, I used 3/4" flat steel
for the sides. The box frame was filled with sand. Stiffeners were welded around
the forklifting channels inside the box, to help prevent the channels from
breaking away from the inside of the box and spilling fill sand where it would
not be possible to repair the channels later. A heavy duty 20 ft. (6 m.) electrical
cable allows my hammer to be connected to any welding electrical outlet within
the shop.
Video clips of STC-88 air hammer operating.
Short
video clips of STC-88 hammer tapering very thin rods and forging leaves.
Tapering video demonstrates the excellent control this hammer has despite being
much too large for the work being done. The second video shows leaves being
forged in two steps, using hand held dies. The dies were made on this hammer
also.
Video data: Tapering video time 0:58, and file size 3.8 MB
http://www.beautifuliron.com/Vid/VinePicketts2007tapersshort.wmv . Leaf
forging video time is 1:51 seconds and file size 7.2 MB
http://www.beautifuliron.com/Vid/VinePicketts2007leavesnarrativ.wmv .
Project
- Vine Wrapped Picketts. The videos linked here (on YouTube) show the entire
project with full narration. Visitors can see that air hammer work makes up only
a small part of the job. After the forging is done, there is still assembly and
cleaning. The air hammer is an asset that makes it easier for the smith to forge
special tooling, and much of the heavier production forging. This video is 12
minutes long and was broken into two parts.
Short video clips of this hammer operating, click on the movie
pictures at right or click the links below. To save this video to your computer;
right click choose "Save target as". Video shows the author's hammer during
shouldering and drawing, cutting, and a maintenance test run.
Video data: http://www.beautifuliron.com/Vid/STC88_Shoulderanddraw.wmv Shouldering
and drawing file size is 1.6 MB and time is 1:34.
http://www.beautifuliron.com/Vid/STC88_Cutter.wmv Cutting video is .98
MB and time is 58 seconds.
More video clips of an STC-88 air hammer forging a 2" bar at the Soluquip website? Go here: *New Link January 21, 2007!
http://www.soluquip.com/Striker_movies.htm
Fabricating the steel work stand
NOTE: when describing the "left" or "right" sides of a machine, I refer to
the machine's right or left, not the user's right or left. In other words the
right side of a machine is on the users left when the user is facing the front
of the machine. Example; the hammer photo at top of this page shows the machine left
side.
Unpacking
the shipping crate. The hammer is very
heavy and must be moved with a forklift. I pushed the hammer as far into
the shop as possible while still allowing space to build the work stand. A lot
of equipment ships with the hammer and everything must be unpacked, inventoried.
The owner's manual includes plans for a concrete work stand, and many of the
items shipped with the hammer are for use with a concrete work stand. As
the project begins, the shop is in total disarray.
NOTE: For safety, after the shipping crate was removed, the hammer remained
bolted to the shipping pallet until ready to place on newly built work stand.
Getting started - initial planning and project development. I chose to
make my own steel work stand. Accurate dimensions were needed before layout and
cutting could begin, so all items unpacked from the shipping crate were moved
away from the hammer to allow the base of the machine to be measured. I made a
set of crude drawings to help plan the work. Measurements were then taken to
determine all "known" dimensions of the lower hammer die, thickness of the steel
floor plate & upper deck plate, and thickness of the wooden cushion planks, and
these measurements were added to the drawings.
What height should the bottom anvil die be?
This was the key dimension that would be used to determine the total height of
the finished work stand. I decided to set the anvil die at 34-1/2" (87cm) above
the floor. Here are the known dimensions that I started with - the anvil die was
21-1/2" (57cm) above the cast machine base, the floor plate was 1" (25.5mm)
thickness, the deck plate was 1" thickness, and the wooden pad between hammer
and deck plate was also 1" thick. Combining all of the measurements listed above
and then subtracting this total from the desired height of the finished hammer
and work stand (34 1/2" - 24 1/2") = 10". The sides of the box frame would need
to be 10" tall.
Measuring
for length of the floor plate. The motor was placed behind the
hammer with belt pulleys aligned, and the total combined length from front of
the hammer base to the rear of the motor was measured. This last measurement was
needed to determine part of the overall length of the floor plate. Every
dimension was double checked and triple checked.
NOTE: that
the floor plate will be 2 inches longer than the total combined length of the
hammer and motor, and the floor plate extends past the rear of the motor to
prevent the motor from colliding with walls or other objects when the hammer is
moved.
Materials. Steel floor plate 1" x 31" x 60". Machine deck plate 1" x 21" x 38".
Box sides and gussets 3/4" x 10" x ?. Wood cushioning boards 2 each -
5/4" Oak 12" x 38". Hammer mounting bolts 4 each - 1" x 7" plus washers and locknuts.
Deck plate (hammer mounting surface) was cut first. The deck plate is 1/2"
longer and 1/2" wider, than the base of the hammer. The deck plate will
extend 1/4" past each side of the hammer base, and extend 3/8" past the front of
the hammer base. This lends support under the wooden pad that will be placed
between the hammer and work stand. No other parts were cut until after all
layout work was completed on the deck plate.
NOTE: the flywheel is fitted very close to the hammer, so the deck plate should
be positioned flush with the hammer base or extend no more than 1/8"
past the rear. Keep it tight in back.
Positions of bolt holes (at the base of the hammer) were transferred to the
deck plate and
double checked for accuracy. This was the time to catch mistakes before the work
went any farther. On my hammer, I found one of the cast
mounting bolt holes to be slightly out of square with the machine. This oddity
was carefully transferred to the layout drawings on the deck plate. The deck plate was marked "this side up" to prevent mistakes, and
1-1/8" bolt holes were then drilled.
NOTE: bolt holes in a cast frame should never be considered perfectly spaced and
should always be carefully measured to accurately determine the exact positions
before cutting and drilling the work stand. Measure and measure again.
Layout drawing of box frame transferred to deck plate. The simplest way
to begin making the work stand is to cut out the upper deck plate (hammer
mounting surface) and then accurately transfer mounting bolt positions from the
hammer frame to the deck plate. The deck plate was then drilled with 1-1/8" bolt
holes and cleaned and de-burred. The deck plate could now be used as an aid to
help plan the layout and dimensions and construction of the box frame.
Planning the box frame. I tried one of the mounting bolts each of the
holes to be sure the there would be enough room to get a wrench inside the
planned bolt hole wells. Drawings on the deck plate were adjusted as needed to
make everything fit before beginning to cut the rest of the steel parts.
Welding the box frame. The box sides were cut from
3/4" x 10" flat steel and welded together. Concentrating on building
the box first without the forklift channel irons. The forklift slots were made
from 2" x 6" channel (inside dimensions are of coarse smaller than this so
forklift forks of about 5" x 1-1/2" will fit in these slots). After the box
frame was welded together I cut the fork channels to length and then cut out the
slots in the corners of the box frame to accept the fork lift channels. These
are not welded together until the next step.
Cutting the
remaining steel parts of the work stand. The 1" floor plate was made 31" x 60" long. The floor
plate would extend 1/2" in front of the box frame, and to the rear the floor
plate extended roughly 2 inches past the rear of the motor. The length of the
floor plate was determined when I took my first measurements of the hammer (see
the entry above titled "Measuring for the length of the floor plate"). The long
extension at
the rear of the hammer work stand would prevent the motor from striking walls and other objects when the
hammer is moved. All corners on the box frame, deck plate, and floor
plate, were chamfered or rounded off to remove sharp corners.
NOTE: the spacing of front and rear hammer mounting bolt holes are not
identical, and the size and position of the front and rear bolt wells are also different. Up to this point in the construction
it wasn't necessary to keep the box facing one direction, BUT now it was
important to orientate the box correctly.
Welding box frame to the floor plate.
The front of the box was placed 1/2" behind the front edge of the floor plate
and centered side to side on the floor plate. The forklift channels were placed
inside the box frame with the open sides of the channel facing down against the
floor plate. The frame was tack-welded to the floor plate, the fork channels were slipped into place
and tack welded, and then everything was welded to the floor plate using full
length beads and welded on both sides.
Reinforcing gussets were needed to support the middle of the forklift
channels and prevent them breaking away from the floor plate if the force exerted
by the forklift becomes too great. To create the gusset shapes, a
cardboard pattern was made to fit closely around the fork lift channels. The
gussets extend 3-1/2" to both sides of each fork channel. The gussets were then cut and welded in place.
The box was filled with sand and the
deck plate was then
placed on the box
and a quick check was made to insure that the front and rear hammer mounting
holes were in the correct position. The upper deck plate was then welded in place.
NOTE: in the photos (at right), the large hole in the deck plate is for filling the
box frame with sand. The sand fill hole will be under the rear frame of the
hammer - not under the anvil block!
Hammer
build-up begins
The
wooden cushion between the hammer and work stand was made from 5/4"
thickness oak boards. The oak boards were place on top of the newly welded top
plate and cutting dimensions and bolt hole positions were scribed onto the
boards. The boards were cut to size and drilled for hammer mounting bolts.
The work stand was moved to its final position in the shop, the oak
cushion boards placed on it, and the hammer was lifted onto the work stand using
the lifting eye provided for the rear cylinder. The hammer was aligned to proper
position by levering it around with a tapered bar placed through the mounting
bolt holes, and the hammer was bolted down. The hammer was now ready for
build-up.
Motor mount
Motor
mounting plate. The large motor mount is made from several pieces of 3/4".
To facilitate the tightening of drive belts the motor mount plate is tipped
sloped to one side of the machine as seen in the pictures. On my hammer base I
chose to move the plate to one side of the hammer so that it extends about 2
inches past the side of the box frame. This proved to be a mistake. I should
have been centered the motor mount evenly between the sides of the box frame. My
side placement caused the motor to need more lateral adjustment to the left to
tighten the belts and consequently I needed to trim the flywheel cover to allow
the motor to move farther to the side. I recommend following the distributor's
design and centering the sloped motor mount below the flywheel rather than
offsetting it like I did.
Motor
tensioner. The motor is connected to the flywheel by 5 drive belts. The
motor must be pushed against the drive belts with enough force to remove all
slack in the belts and prevent slippage. This called for a sliding tensioner
plate between the motor and motor mounting base, and threaded rods and nuts to
force the tensioner and motor against the belts.
Throttle linkage & treadle guard
Adjustable throttle linkage.
The STC-88 looks like a miniature Chambersburg. All dimensions are literally
scaled down in size. The working surface of the lower die is therefore 21 inches
above the bottom of the hammer. Too low to work on comfortably if the hammer was
placed at ground level.
The purpose of the work stand was to raise the hammer up to a more convenient
height for working. But raising the hammer brings the height of the treadle up
also. So the treadle mounting bolts are removed and welded to the sides of the
box frame. Moving the treadle downward requires an extension of the throttle
control linkage. But what length is best? And could this length be adversely
effected if the treadle is adjusted forward or rearward on the machine at a
later date? Again what effects would need to be countered with the throttle
linkage?
I solved this after moving the treadle and cutting the throttle link
approximately 3-1/2 inches from the lower connection (near the treadle), and
welded a of 5/8" threaded rod to the short section of throttle link. The long
upper section of throttle link was punched and drifted in the forge to
accept the 5/8" rod and then bent the end 90 degrees so that the 5/8 inch rod
could be inserted through the drifted hole and adjusted by use of the nuts
installed on the threaded rod. The link was reinstalled on the machine and with
4 nuts installed on the threaded rod, I adjusted the linkage for best effect.
The threaded rod will insure the ability to adjust the treadle as needed in the
future.
Treadle
guard. The purpose of the treadle guard is to prevent the treadle from being
depressed if any part of the work should happen to fall off the hammer during
forging. This includes tooling and other objects that are laying on the scale
pan that might fall off the pan and strike the treadle while the hammer is
running.
The treadle guard seen here is made of 1/4" x 3-1/2" flat steel, welded all
around the top of the work stand frame box. The treadle guard is welded high
above the treadle. The large gap between the treadle and guard allows me to
place the large steel toes of my work boots between the guard and treadle more
easily.
The treadle guard on my hammer is cut with a slight taper towards the
rear end of the guard similar to the angle that the treadle is bent towards the
pivot.
Oil sump reservoir
Oil recovery reservoir. The
smaller hammers (STC-55 & STC-88) are basically a simple
design such as might have been common around the early 1900's. There is no oil
sump pump that would have pumped oil to the cylinders or returned it from a sump
to an oiler reservoir. Instead the oil simply drains from a hole at the base of
the frame below the rear cylinder. I use a plastic oil can to catch the oil that
drains from the sump. The oil can is a typical 1-Quart (US measure) as used for
automobile motor oil. The oil level in the container is conveniently visible
through the sight strip on the rear of the container. The recovery containers
are oriented so that the sight strip is facing forward and the oil level inside
the container is visible to the operator while standing in front of the hammer.
The drain tube from the hammer sump is fitted through a hole bored in the
recovery-container cap. I fabricated a bracket to
support a pair of these used motor oil containers placed side by side. The
bracket was welded to the side of the work stand behind
the right side treadle mount. After one container is full, I will simply switch
the tube and cap to the other container and either recycle clean oil to the drip oiler
or discard dirty oil with a the rest of my used oils at a recycling center.
Electrical service
Overview
of motor of electrical installation. The electrical installation shown here
is very different from the vendor's working showroom demonstrator hammer
installation. I have three concerns about how
electrical installation should be performed on my equipment. #1.) The rear of my
hammer is near the large entrance doors at the front of my shop, the doors are
poorly sealed and allow snow and rain to fall on the rear of the hammer. All
motor electrical wire runs and panels therefore require weatherproof outdoor
style wiring. #2.) I want the power cable to enter and terminate in a service
disconnect box on the back of the hammer to limit damage to the cable and
disconnect box connections, in the event that personnel or machinery trip over
or snag the power cable and pull it out of the disconnect box. #3.) I wanted the
starter to be mounted on the machine - not beside it. And I wanted simple
conduit protected wire runs from starter to the disconnect box and to the motor.
Electrical disconnect box at rear of work stand. Click on the
thumbnail photos at right and take a close look at the bracket supporting the
disconnect box. The disconnect box is located on the rear of the floor plate
next to the motor. The mounting bracket is a simple affair made of
1/4-inch x 2-inch angle iron with a 1/4-inch x 4-inch square plate welded
perpendicularly across the bottom and another similar size plate welded at the
top for mounting the disconnect box. The plates are of coarse drilled for
bolting the disconnect box and bolting to the floor plate. A piece of 1-inch x
4-inch square plate was drilled and tapped for 1/2-inch bolts, and welded to the floor
plate, next to the motor. In this way I could assemble the disconnect box with
the mounting bracket and then quickly bolt everything down to the floor plate.
Swiveling bracket on side of hammer
supports starter box. The
Striker™ hammer was provided with a separate stand for mounting the motor starter but, I chose to instead place the starter on
the side of the hammer. A two-piece forged bracket was bolted to the
top of the rear cylinder using the lifting eye and one of the cylinder head
bolts. The top plate of the bracket is offset approximately 3/16ths inch to lay
flat across both the center and sides of the cylinder head. The two-piece
bracket is assembled with a single bolt to allow the starter mount to be
swiveled into desired position before tightening the bracket together. The
starter was bolted to the bracket. This setup places the starter box in a
location that I find to be most ideal for operating the hammer.
NOTE: this is a single-phase 220volt installation in my shop.
Overview
of wiring runs. The power cable enters the bottom of the disconnect box.
Click on the thumbnails of the disconnect box at right. There are three wires in
the cable, black and green are hot 220-volt wires. The beige color wire is a
neutral and I connected it to the common ground lugs at the left side of the
box. This neutral line is also grounded in the main power service panel that
enters the shop. The hammer electrical circuit is grounded for safety.
Red and blue hot wires from bottom of disconnect breaker are routed through
conduit to the 'L' terminals of the motor starter. Green and black wires from
the 'T' series terminals (from bottom of motor
starter/overload breaker) are routed back through disconnect box and through conduit to
motor. White neutral wires are connected from the common ground lugs in the
disconnect box, to the ground lug in the motor, and to the neutral lug inside of
the motor start relay box.
NOTE: the neutral lug inside the motor starter box is a dead end. I
included this wire for future modifications that would use the starter wiring.
The Kwikstarter magnetic motor starter shown on this page is used for
single-phase and 3-phase applications and is manufactured by Sprecher-Schuh.
Note that the starter shown here has been rigged for single-phase use. This is a
complete self-contained motor start with overload protection pre-installed in a
small box. Sprecher-Schuh website is here:
http://www.ssusa.cc/ . Sprecher-Schuh has posted a library with
documentation on all their products including wiring diagrams and technical
drawings. Check this library if original documentation that came with the
hammer, has been lost. For more about installation of the Kwikstarter see item
#2 in the Troubleshooting section farther down on this page.
Magnetic motor starter - theory of operation. With the push of a button, the motor
starter connects the motor to a power source through contactors and maintains that connection by
the use of electro-magnetic attraction until electrical power is lost
or until the starter senses a jam or over-current condition, at which time the
electro-magnetic circuit is broken and the contacts separate. Motor start
relays allow fast switching of high current circuits without excessive
burning of switching contacts. Modern motor starters are often provided with
built-in or add-on overload protection devices. The motor starter seen on this
page is provided with an add-on overload breaker mounted below the start relay.
The theory presented here describes only the operation of the starter seen
on this page.
NOT DONE
Lubrication & oiler operation
Grease & oil requirements.
Use the best grease available. I recommend using the best molybdenum marine duty
grease. Oil specifications may vary according to hammer size, so hammer owners
should consult the literature supplied with their hammer to find the oil
specified for use with their hammer.
Bearing lubrication - 3 grease zerk locations
Lubrication reference data placard attached to lower right side of hammer
frame. Of the three brass placards attached to right side of the hammer
frame, the largest placard mounted near the bottom of the hammer, offers a quick
reference to locations of bearings that require periodic lubrication (greasing)
and maximum time interval between each lubrication sequence.
Warning! Electrical power must be locked out before removing guards and
opening access panels!
NOTE. Paint and seals are likely to be damaged during typical
maintenance activities. The silicone sealant is cheap to replace, and new paint
can be applied over scratches.
Guards and access panels must be
removed to lubricate the STC-88 hammer. Some new hammer owners might be a
little uncomfortable disassembling their machine and damaging the beautiful
paint job. Removing guards and access panels is part of routine maintenance.
Lubrication is a requirement! Two grease points are located inside
the hammer frame and both access doors must be removed to gain entry for
lubricating these internal grease zerks. A third grease point is located behind
the flywheel, so the flywheel guard must be removed to access this grease point. See the photos at right.
Warning! Flywheel and crankshaft could move
unexpectedly and cause serious injury!
Front crank bearing and pitman bearing grease points. The front crank
bearing is accessed by removing the left-side access panel.
The pitman (connecting rod) bearing is accessed by removing the right-side access panel.
Rear crank bearing grease point. The
rear crankshaft bearing grease port is located between the flywheel and hammer
frame. It can be seen through one of the lightening holes in the flywheel. The
port is sealed with a check ball. This is a very small port so it may be
necessary to first clean the back of the machine to find the check ball. A needle tip
attached to the
grease gun is used to force grease into this port.
Re-sealing and re-installing access panels. Panels are fastened with two
bolts. These bolts are snugged down - NOT cranked down super tight! A soft seal
will prevent leakage. If the seal leaks then replace the sealant - Don't crank
the bolts down tighter. Over-tightened bolts could break the panel. Panels are
sealed with silicone sealant. I prefer to reuse the seals if they are not too
badly damaged after removal. If seals are too badly damaged to re-install, I
remove the old sealant and thoroughly clean and degrease the panel seal area,
and apply a thin coat of silicone sealant and re-install after the sealant
skins.
Grease
zerks installed in treadle pivots. The pivoting mounts of the treadle are mounted on bolts
welded to the side of the steel work stand. These are the original treadle pivot
bolts that came with the hammer and originally installed on the hammer frame
near the middle of the bottom edge of the hammer frame casting. The problems
with pivots is the dry condition
appeared to make the joint a candidate for a great deal of wear. I drilled the
treadle brackets slightly, off-center to the top of the pivot hole, then tapped
the hole for 1/8" pipe and installed a grease zerk in each of the treadle pivot
brackets.
Drip Oiler - Overview
Drip oilers
used on small hammers such as the Striker STC-88 (photo at right) consist of a
reservoir with distribution and metering manifold, priming pump, check valves/one-way valves, and hammer
cylinder oil supply tubes. The entire oiler system is externally mounted on the
right side of the hammer. Drip oilers operate on pressure differential caused by
the hammer cylinder rams moving across the open oil inlet ports (where the oil tubes/check valves thread
into the cylinders). Atmospheric pressure forces oil in the reservoir to flow through the oiler system
to fill the momentary low pressure at the oil inlet ports at the hammer cylinders. Metering valves control the
volume or rate of oil flow during hammer operation and the valves are fully
adjustable by hand. Drip domes on top of the reservoir manifold allow the blacksmith
to monitor oil flow. An oil level sight glass (small window) on the front of the oiler reservoir will show a bubble when the oil level is low.
Oil system priming required before hammer start. Priming should be done
at the beginning of each day before starting the hammer and anytime that the
hammer has been idle for more than a couple hours. It is normal for oil in the
supply tubes to slowly drain back into the reservoir when the hammer is not
operating. The primer pump is used to
purge air from the oil lines and to force oil to flow through oil tubing to
begin initial lubrication of the cylinders. Transparent plastic oiler tubes
allow the blacksmith to observe the oil and/or air in the tubing. Owners of
hammers with metal cylinder oil supply tubes cannot see the oil and/or air in
the tubing and therefore should assume that the tubing has completely drained of
oil after the hammer has been idled for roughly 8 or more hours, and prime the
system fully as described in the section below sub-titled 'Operating the priming
pump.'
Drip Oiler - Operation
Check oil level. Check that the oil level is not low (no bubble in the
oil level sight glass). Fill the reservoir with oil if a bubble appears in the
oil level sight glass.
Metering valves must be open for oiler operation. Open the
metering valves if they are not already open at this time. Do not omit this step-
valves must be open for oil to flow. The metering valve knobs
are adjusted by hand, and they are also provided with screw driver slots in case
they become stiff or difficult to turn by hand. Turning them clockwise
restricts or shuts off oil flow. Rotating the metering knobs counter-clockwise opens
them and increases oil flow. The exact valve setting is not
important at this time because the valves will be tuned to proper oil flow after hammer start. If
the valves are already open due to previous hammer use then leave them alone.
HINT: Temperature & oil weight/viscosity will directly effect the volume of oil
that flows at any given setting of the metering valves. The colder the oil, the
slower the oil flows and the more the valves will need to be opened. The warmer
the oil, the easier and faster it flows and the more restricted the valve
settings must be.
Operating the priming pump. Push the primer handle towards the hammer to
make sure that it is all the way back and then pull outward on the handle and
hold for 1 or 2 seconds. Repeat as many times as necessary to completely purge
all air out of the oil tubes It is normal for oil to flood the drip domes so
that it is not possible to observe oil flowing out of the drip tubes while
priming. As long as the drip dome can be seen to become flooded while pumping
the handle, and a slight back pressure can be felt each time the handle is
actuated, it can be assumed that oil is flowing properly within the system. If the oil fills the drip domes
too slowly, then open the metering valves a little more and continue actuating
the primer. After purging all air out of the oil supply
tubes, continue operating the primer handle another 5 times to begin initial
lubrication of the hammer cylinders. If oil does not flow, check that the
metering valves are open and then repeat this step.
How many times must the primer handle be pushed and pulled to prime the
system? There are two different methods for priming the oiler system.
The first method assumes that the hammer has been in use very recently
and the metering valves were already opened and set under similar temperature
conditions. This is the method I use in my own shop most often. There will be
less oil flow when using this method compared with the second method described
below because the metering valves are already set to restrict oil flow and there
is more resistance to priming. Push and pull the primer handle approximately 20
to 25 times for hammers with plastic oil supply tubes (approximately 15 to 20
times for hammers with copper oil tubes). Around 3/4ths of the way through the
priming, the oil tubes are fully primed and the last five actuations on the
priming handle force oil into the hammer cylinders for initial lubrication.
The second method is for valves that have not been set previously. Open the
metering valves wide open. Push and pull the priming handle 5 or 6 times. Oil
will quickly flood into the drip domes and into the cylinder oil supply tubes.
One or two additional push and pulls on the priming handle and a large amount of
oil is forced into the cylinders for initial lubrication. This alternative
method may appear faster and easier compared to the first method described above, but
will take longer to set proper drip volume after start up, and check valves do
not close fast enough to prevent some of the oil from flowing back into the
priming pump when the handle is quickly pushed back to recharge it.
WARNING: It is common for a self-contained hammer to strike a blow once during
startup when the throttle is placed in the 'Lift' position. Before starting the
air hammer, make sure that all guards and covers are properly installed, work
area is cleared of objects that could interfere with hammer operation, and warn
anyone nearby that the hammer is going to be started. Serious injury can result
if objects are pressing against the air throttle or come in contact with the
moving parts of the air hammer, or if persons are touching parts of the hammer
that will begin to move during hammer operation.
Start and run hammer - monitor oil flow in oiler drip domes. Start the
hammer and set throttle to 'Lift' position. Move around to a location near the
hammer that allows the user to both monitor oil flow in drip domes and step on
the throttle treadle at the same time. Hold down the throttle treadle to make
the hammer ram begin reciprocating up and down until hammer dies almost touch.
Observe oil level in the drip domes as the ram is cycling up and down.
Continue operating the hammer as the oil drains out of the drip domes and the drip tubes finally
begin to drip oil within the domes. After several minutes the oil flowing
through the drip tubes will stabilize to a predictable number of drops/per
minute. When the metering valves are wide open, oil will flow out of the drip
tubes as a small steady stream. If no oil is seen dripping from the drip tubes,
then look closely inside the drip domes to see if indeed the oil is flowing as a
steady stream.
Adjusting oil flow. After running the hammer for several minutes and
observing that the amount oil dripping (flowing) from the drip tubes has stabilized, it is
now time to set the exact number of drops per minute in each drip dome. Continue
to hold the hammer throttle treadle down with the dies almost touching while the
ram cycles up and down. Choose a drip dome zone to adjust first and adjust the
appropriate metering knob to either slow or increase the frequency of drips in
the drip dome as desired. Turn the metering knob clockwise to restrict oil flow,
or counter-clockwise to increase oil flow. Continue cycling the hammer ram and observe that the
oil flow in the chosen drip dome has stabilized to the desired number of drops
per minute. Adjust again if necessary. Now adjust the second metering valve
using the same method. Follow the manufacturer's or vendor's recommendations for
the appropriate amount of oil flow (drops per minute) suggested in the
literature shipped with each hammer. The metering valve knobs have no jam nuts so they are
simply adjusted and then left alone. The hex head fitting beneath the valve is
part of the valve and seat installation and should not be turned or tampered
with.
Periodic oil level check. Oil level should be checked after every couple
hours of hammer operation. If a bubble appears in the site glass, then it is
time to refill the reservoir.
Re-establishing primer pump oil flow after low oil
level has occurred. There are two methods for re-establishing oil flow and
these methods have metering valve positions similar to those described above in
'Operating the priming pump' above.
Method one assumes that the blacksmith has recently stopped hammer operation and
to immediately re-fill the reservoir with oil. The metering knobs are already
open and set for proper oil flow. Refill the reservoir with oil, then push and
pull the priming handle as many times as it takes until the drip domes fill with
oil. Remember to hold the priming handle out for one or two seconds before again
pushing the handle back in. Check valves move slowly and require a second to
close before the priming handle is actuated in each direction. The restricted
condition of the metering knobs will slow the flow of oil, and as oil begins to
refill the oiler system, a small resistance will be felt against the further
pushing and pulling of the priming handle. Primer pump oil flow is
re-established when oil begins to fill the drip domes.
Method two is best when metering valves were closed previously or when method
one above doesn't appear to work. Open the metering valves wide open (1 or 2
full turns counter-clockwise). Refill the reservoir with oil, push and pull on
the priming handle as many times as it takes until the drip domes fill with oil.
Remember to hold the priming handle out for one or two seconds before again
pushing the handle back in. Check valves move slowly and require a second to
close before the priming handle is actuated in each direction. Oil will quickly
rush in to fill the drip domes. There will be no resistance felt on the priming
handle because the metering valves are wide open and present no restriction to
oil flow. Primer pump oil flow is re-established when oil begins to fill the
drip domes.
After primer pump oil flow has been re-established continue priming the oil system as
described in the previously in 'Operating the priming pump', in preparation for hammer run. If the
method described here for re-establishing oil flow fails to bring the oiler back into normal operation,
check that the metering valves are open, proper weight of oil is being used, and that the oil reservoir has sufficient
oil level to operate the priming pump (no bubble in oil level sight glass).
Filling the oil reservoir. Oil should be added when a bubble first begins
to appear in the oil level sight glass. Note that the oil supply is drawn
through the priming pump, so the priming pump must be submerged in oil at all
times to prevent air from being ingested into the oil supply. When the bubble in the
sight glass is below the middle of the sight glass, the priming pump is no
longer submerged in oil. A fill plug is located near the middle of the front edge
on top of
the reservoir. The fill plug has a breather hole to allow
aspiration of the reservoir. The fill plug is installed finger-tight, and is
removed by hand to allow access for filling the tank with oil. A fine wire mesh
screen is installed in the fill hole to catch any dirt or debris that may
accidentally fall into the reservoir. The screen is very fine and will
cause the tank to fill very slowly, consequently the smith must add oil slowly
and be careful to seal the spout of a funnel tightly in the fill hole to prevent
leaking or spilling of oil.
How much oil is needed to fill the oiler reservoir? The quantities of oil
described here are for the oiler on my STC-88 air hammer. Total capacity of the
oil reservoir when empty is approximately 27 (US) ounces. When a bubble appears
at the top of the sight glass, approximately 20 (US) ounces of oil is needed to fill the reservoir. If the bubble appears in the middle of the sight glass,
roughly 23 (US) ounces will
be needed to fill the reservoir to full again. 28 ounces is equal to 1 (US)
quart.
The
priming pump. The handle on the side of the reservoir actuates the priming
pump. Pulling outward on the handle forces oil through the system, and pushing
inward on the handle refills/recharges the priming pump. Check valves (one-way valves)
installed inside the primer pump direct oil into and through the priming
pump as the handle is actuated. The primer pump plunger fits loosely inside the
pump block. There are no seals in the primer pump mechanism. Sealing and
lubrication of the plunger is dependent on proper viscosity of the oil and the close
proximity of fit between the moving parts of the priming pump.
HINT: Using low weight/low viscosity oil will cause poor oiler performance and
primer pump malfunction. The oiler requires high oil viscosity to function
properly, so follow the vendors recommendations as to oil weight requirements.
When filled with the correct weight of oil, the oiler and
primer work well.
Initial path of oil flow. During normal oiler operation, oil first enters a small hole drilled in the primer pump block. Flowing through the main primer pumping chamber, oil
enters the capillary in the back of the oiler housing. The capillary is visible as a large 5th hole
(in the photo at right) in the middle of the back wall of the disassembled oiler body.
Reservoir cover & oil metering manifold.
The top cover of the reservoir contains an oil manifold to meter and
distribute oil to each output tube or zone.
There are two metered oil outputs, or zones, left zone/compressor cylinder and
right zone/ram cylinder. Volume of oil flow in each zone is controlled by adjusting
the metering valves to increase or restrict flow as desired.
Oil flow through metering valves. Oil enters
the main oil gallery inside the reservoir cover by way of a small hole that
connects with the capillary in the back of the reservoir. A pair of zone capillaries drilled
from the side, through the middle of the reservoir cover- connects the metering
galleries with the main oil supply gallery. Metering
galleries are drilled from the front of the reservoir cover- through the zone
capillary passages, terminating in a connection with the drip tube passages underneath the
drip domes. The working end of each metering valve consist of a needle and seat installed
in the metering gallery between
each main oil supply and drip tube gallery.
Drip domes and visible oil flow. A pair of
transparent (see-thru) drip domes on
top of the reservoir cover/manifold allow the hammer operator to monitor oil flow and
operation of the oiler.
With the metering valves open, oil flows through the meter valve galleries,
and then through the drip tubes visible through the transparent drip domes on top of the oiler.
A small hole drilled in the bottom of each drip dome connects with
a zone passage to the output check valve
supplied by that drip dome (left drip dome- left output check valve fitting, and
right drip dome- right output check valve fitting). Oil from the drip domes flows through
the zone supply passage, out through the output check valve, through the cylinder oil supply tube, and finally through
a second check valve into the hammer cylinders.
Check valves & oil tubes.
Check valves direct oil flow in one direction- towards the hammer cylinders.
There are four
check valves located outside of the reservoir (two output checks located inside the hose fittings on top of the oiler, and
two input checks threaded into the sides of the hammer cylinders (one in each cylinder).
Output check valve fittings on the rear
corners of the reservoir prevent oil from flowing backward into the reservoir
manifold. The output check valves allow
oil to flow one way - out of the hose fitting side of the valve. Input
check valves (one threaded into the side of each hammer cylinder) prevent air in
the hammer cylinders from being forced into the oil tubes while the hammer is
running. Input check valves allow the oil to flow
one way - into the hose fitting side of the valve- into the hammer
cylinder.
The drip oiler system uses atmospheric pressure to operate. Consequently
the spring pressure on the check valves must be very light. While the oiler is
operating, the check valves prevent back-flow and direct the oil to the hammer
cylinders. But when the hammer is not running, the oil will slowly seep through
the check valves and drain back into the reservoir. The light pressure on the
check valves cannot prevent slow leakage while the oiler is not in use. This is
why the blacksmith will find the oil lines empty after the hammer has been idled
for more than a couple of hours. The drip oiler works by pressure differential
between the reservoir and the oil inlets will be no more than one atmosphere
(approximately 14 lbs/inch at most).
Oil viscosity and resistance to oil flow inside the oiler system.
Viscosity of the oil, resistance of the check valves, friction of oil flowing
through passages and tubing, and restriction of oil flow through the metering
valves creates a resistance to the flow of oil through the oiler system. The
greater the total resistance to oil flow- the less volume of oil flow over a
given period of time. And the less the total resistance to oil flow- the greater
the volume of flow over time. The metering valves offer an infinitely variable
rate of resistance to allow the smith to fine tune the total resistance, and
ultimately control the total oil flow. The drip oiler will not work with low
weight/viscosity oil. The check valves are not strong enough to prevent the
back-flow of the thinner/lower viscosity oils. And the priming pump does not
work well with low viscosity oils because the oil can easily bypass the system
by flowing around the sides of the priming pump plunger. Using an oil of too
heavy weight or high viscosity will cause too much resistance to oil flow and
consequently the total volume of oil flow will be too low. Temperature will also
effect viscosity of oil. In some climates it may be necessary to use a lighter
weight oil during winter and a heavier weight oil in summer. Follow the
manufacturer's or vendor's recommendations concerning proper oil weight and be
ready to modify the oil weight to compensate for climate or temperature in the
shop.
Drip oiler - disassembly, repair and maintenance
Disassembling the reservoir for maintenance.
The reservoir assembly must be removed from the side of the hammer before
disassembly because the gallery core plug on the rear of the manifold is pressed tightly against the hammer
frame while the reservoir assembly is installed on the hammer. Before removing the
reservoir from the hammer, the oil hoses should be disconnected from the check
valve fittings on the top of the manifold. The reservoir is then unbolted from
the hammer frame and placed on a work bench for disassembly. Keep the tank
upright to avoid leaking and spilling oil. There are four socket head screws
holding the reservoir cover/manifold in place (one screw in each corner of the
cover). After removing these screws, keep the tank in an upright position and
carefully pry the manifold off the tank-being careful to avoid tearing the
gasket seal between the main body and manifold cover, and also to avoid damaging
the fine wire-screen mesh that hangs
down inside the reservoir tank. After removing the top of the reservoir, the
tank can be drained and set aside. The plugs in the side edges of the manifold
should not be removed for any reason. These plug the machined holes that were
part of the manufacturing process and are sealed to prevent oil leaks and/or
seepage.
Oil level sight glass. The oil sight glass has a 42mm
x 1.5mm threaded barrel
and rubber seal, and is threaded into the front of the oiler reservoir. A special
spanner wrench is used to remove and install the plastic sight glass. I made my spanner wrench from small
piece of flat steel with 1/8" (2.5mm) pins
welded to the ends. New plastic sight glasses can be obtained from Striker Tool
Company. Expensive aluminum barrel sight glasses with scratch resistant glass
can be obtained from J.W. Winco and from MSC Industrial.
http://www.jwwinco.com/ and
http://www1.mscdirect.com/
Drip Domes. Drip domes are threaded into the top of the manifold. If they
become broken, the hole can be cleaned out and new drip domes threaded in place.
Input and output check valves are NOT interchangeable. To determine which
direction the oil flows through the valve, clean the valve, blow through it and
see which direction the valve allows air to pass.
Drip oiler - theory of operation
--Not
finished--
A
short summary of path of oil flow.
Break-in & initial inspection
Initial inspection. Before operating the hammer I attempted to grease the crank shaft bearings
and pitman bearing using the existing grease zerks. The zerks proved to be very
poorly fitted and required replacing before grease could be applied to the
bearings. For anybody reading this that isn't sure what I meant by poorly fitted
zerks, it means that I expect to be able to force ALL grease into the bearing
and not find grease flowing out around the sides of the zerk or all over the
place. All grease needs to go to the bearing, and if a zerk does not allow for
this then it must
be replaced. It was necessary to replace the existing zerks with new ones. See
the pictures at right.
Establish primer pump oil flow in the drip oiler and prime ail system and
tubing. Following procedure for re-establishing oil flow when the pump has
ingested air due low oil level.
Lighter weight oil used for break-in. For break-in only, I used
Sunoco ISO 46. I switched to a heavier weight after initially using
about 1 gallon of lighter weight oil during break-in.
Hammer is shipped with preservative coating on machined surfaces. The
preservative prevents rust
from forming on the machined surfaces during shipment and storage. The preservative will dissolve when the hammer is
run for the first time. Oiler flow adjustment screws were opened wide for
maximum oil flow during initial startup. Oil must be allowed to flow freely to
dissolve and wash away the preservative coating on the machined parts. Some of
the free oil will flow out of the front hammer cylinder onto the bottom
die block and I kept rags nearby to wipe up the excess oil during break-in. Oil
from the rear cylinder falls into the sump inside the hammer frame and drains
out through a tube into a catch container.
Break-in involves operating the hammer with the ram reciprocating up and down almost a
full stroke but not allowing the dies to strike. Drip oiler adjustment screws
were opened wide so oil would flow freely during break-in operation. The large
volume oil flow is for break-in purposes. A block was placed under the rear of
the treadle and adjusted as needed to keep the hammer running by itself while I
monitored hammer operation. It is wise to never allow a hammer to operate unless
the operator is nearby. With the oiler running wide open, excess oil leaks out
of both cylinders, and after the color of this leaking oil began to clear up, I adjusted the number of drips
visible in the clear domes to about 20 to 25 drops per minute. Oil leakage continues to be dirty in color, so I let the hammer have
lots of oil to clean itself during break in. Oil feed will be adjusted to about 8-12 drops per minute after hammer
wear in.
Check
direction of flywheel rotation. Rotation must match the direction of the
arrow placard that is riveted to the top of the flywheel cover. See the photo at
right. The rotation direction must be corrected if it does not match the arrow
placard. For more about this task, see problem #3 in the Troubleshooting section
further down this page.
Trial run. First task with my new air hammer was to make handles for
hand-held air hammer tooling. From a 1-1/2" x
1-3/4" bar I was able draw a 12" length x 1/2" thickness x 2-1/4"
width in a single heat. This hammer replaced my old Little Giant 25lbs hammer
and there is almost no comparison. The Little Giant would have taken more than a
dozen heats to do the work that this hammer did in one single heat.
Safety
WEAR SAFETY GLASSES! The most important tool in the blacksmith's shop is
safety glasses. Look closely at the photos at right. The scale can be seen
flying up off the scale pan due to the shock and vibration during hammer
operation. Everyone working with or near an air hammer should be required to
wear safety glasses while the hammer is operating. During routine hammer
operation this author has been sprayed with hot scale as a result of vibration,
bending, welding, drawing, and also when oil and water was present on the hammer
dies during forging. Other hazards include flying objects as hot iron was cut or
tools broke under the air hammer. Despite this there have been no serious
injuries. Safety glasses are a requirement in my shop. Make safety a part of
your work too! Good safety habits reduce or prevent injuries.
Beware of position of the work piece and tooling at all times while using
the hammer. The force of hammer blows can cause the iron or the tooling to jump
forcefully and unexpectedly while the workman is holding them. The work piece
and tooling can cause injury to the operator and others nearby if the operator
fails to maintain proper positioning of tooling or work piece on the hammer.
Tooling should be held in perfect vertical alignment. Any tooling held at less
then perfect alignment risks that piece breaking or being sent flying across the
shop. This rule also applies to the work piece that is being forged.
Oil
or water on die surfaces will cause a burst of high pressure steam or gas
resulting in scale being blown off the surface of the hot iron in all
directions. It is normal for oil to drip from the front ram cylinder of an air
hammer onto the bottom dies, and often after the hammer has been idled prior to
forging, the first blows will result in a visible burst of flame and hot gases.
Additionally any lubricants or coolants applied to dies prior to forging hot
iron will result in a burst of flame and hot gases when forging begins again. It
may be necessary to keep people away from the hammer during operation, or at
least make them aware of the hazard described here.
Remove trip hazards and other entanglements from the work zone. The working
area of an air hammer is necessarily open and unobstructed to allow free-style
work methods. This open and unguarded condition also makes it possible for tools
and other objects, or the operator's body, to come into contact with hammer dies
accidentally. Keep the work area clear of any obstacle to the work.
Lock out energy sources before performing maintenance. Electrical service to
the hammer should always be locked out before attempting to change dies, attach
tooling to the hammer, and when working on any part that moves or stores any
form of energy during operation. Lock it out! This machine can cause serious
injury if it starts unexpectedly while the workman is performing service or
maintenance on the hammer. For anyone that doesn't understand what this means,
enter these key words in your search engine- "Lock out tag out procedures".
Books and resources for air hammer owners
See the
Forging
Hammers Resources page
http://www.beautifuliron.com/gs_forging_hammer_resources.htm for a small but
growing collection of books and other resources for training and instruction for
working with forging hammers.
Tools for use in air/steam forging hammers (Vendors &
Distributors)
Glendale Forge, made in Britain.
http://www.glendaleforge.co.uk/
Swages, cutters, and other forging tools for use in forging hammers. A small set
of basic hand tools for use on open die forging hammers. If a smith is looking
for ready-made tools for use in their air hammer, the tools offered at Glendale
look very useful.
Centaur Forge
http://www.centaurforge.com/ previously offered custom made hammer dies,
spring swages, and a set of hand-held chasing punches made by Glendale Forge.
These were available in their 2003 catalog. But the hammer tooling is not seen
on their website. I don't know if they continue to offer these tools or if the
tools simply don't appear on the Centaur website.
Making tools for the hammer, I currently use 4132 oil hardened
molybdenum alloy steel.
My larger tools such as hand-held hammer eye punches are roughly
2-1/2 inches to 3 inches tall. Handles were fashioned from a bar of 3/4 inch
round steel. Handles forged with nice long thin tapers and flat section near the
tool end forged wide and thin from the original 3/4 inch round bar section. The
flat section absorbs shock and concussion.
Drawings
& Worksheets.
The
crude drawings at right are the same drawings I used to set up my machine.
NOTE: The spacing of the hammer mounting bolt holes on the
left side of my air hammer are different from the bolt spacing on the right
side. This anomaly in bolt positions in large castings is very common and I
strongly recommend everyone check
hole spacing prior to marking and drilling the hammer mounting holes.
Troubleshooting.
There are several problems that the new hammer owner is likely to encounter.
I encountered some of these during setup of the hammer on this page. Fortunately
I had experience wiring electrical motors for industrial applications. But if
the new hammer owner isn't proficient in electrical work in the shop, these can
be impossible to solve. Here are some common problems and solutions:
1.) PROBLEM: Motor starter relay operates (pulls in and seals) correctly
when start button is pushed, but motor does not energize (no electrical power
to motor). For 240v single phase only.
Relay
may have been wired incorrectly by factory. This happened to me- one of
the wires had been connected to the wrong terminal on the relay. The wiring diagram (near right) shows three configurations
for 3 different voltages and phases. Note that the diagram does not
show the fourth (spare) set of contacts that are available on the motor
starter relay. I have modified the 240v single-phase diagram (second
right) to show the NO contacts. The NO contacts are not part of
motor run circuit. NO means 'Normally Open.' All of the contacts are in fact
normally open, but only the 'L' series and 'T' series connections are part of
the motor circuit. The NO contacts are spares available for other optional
use.
If the black jumper wire was connected from the T2 line at the
bottom of overload device, to the NO contacts (far right side
connector) on top of the line relay. That is what I found when inspecting the
wiring on my new hammer motor starter. The starter can't energize the motor if
the single phase jumper is not connected with a line circuit through the relay
and overload device. The hammer will not run if wired incorrectly.
SOLUTION: There are 4 sets of contacts on the starter relay (L1, L2,
L3, & spare NO), and there are 3 circuits in the overload device(T1, T2, T3).
The 240v single-phase diagram shows a jumper wire between T2 & L3. I had to
move this jumper to connect from T2 on the bottom of the overload device to L3
at the top of the relay. At far right is a picture of the motor starter relay
and overload breaker on my hammer, showing the correct wiring setup for 240v
single phase. The NO contacts are the unused fourth set of connections at the
right side of the starter relay. See the photo of completed starter circuit at
far right. This is exactly how it should look when the circuit is correctly
wired for single phase 220v without an emergency stop line.
2.) PROBLEM. The starter does weird things like rattle back and
forth and will not stay connected on its own, tripping the circuit breaker in the overload device, and the motor won't
come up to full speed and appears to lack the large amount of torque required
to start and operate an air hammer. (for 240v single-phase systems only)
SOLUTION: Possible error might be that one of the two hot wires has been mixed up
with the ground or neutral wire, creating a 120v circuit by accident. If the
wall outlet is known to be correct, then wires could have been mixed up inside
the plug, wires mixed up inside the service box on the hammer frame, wires
mixed in the L1 and L2 and neutral connectors. Use a notepad to write down all wire colors used and compare with
wiring in each box or plug. Are all wiring notes in agreement with the colors
found in each box and plug? Make wiring connections to the proper terminals to
match the diagram.
3.) PROBLEM. Motor turns in wrong direction.
There is only a 50%-50% chance of getting it right the first time when
connecting the motor wiring. No harm done if it is backwards when first
starting the hammer, but excess wear of compressor cylinder may occur if
allowed to continue. Compare the rotation with the arrow placard riveted to
the top of the flywheel guard.
SOLUTION: To change the direction of flywheel rotation, disconnect
and lock out electrical power to the hammer, and change two wires inside the motor connections box on the side of the
motor. Single phase: swap the #5 and #8 wires and re-connect. 3-phase: swap
two of the three T-leads and reconnect. And any time that work has been
performed on shop wiring involving 3-phase circuits, the hammer flywheel
rotation must be checked each time, because any changes to the main 3-phase
circuit can and will result in 3-phase circuit changes at the hammer and
possible reversal of motor rotation at the hammer.
4.) PROBLEM. Motor makes a growling noise when energized but does
not turn. Three phase only!
One leg of the three phase power circuit to the motor, is open. A growling
noise and non-rotation of a three phase motor is the classic sign of 'single
phasing'. Three phase motors need all three legs in the circuit to operate.
Cut one leg and the motor sits still and growls.
SOLUTION: Check any fuses or circuit breakers that supply power to
the hammer. Isolate the fuses to prevent feedback current from giving a false
reading. More skilled electricians can check across two different fuses to
find the defective one. If fuses and circuit breakers are all good, then check
connections at motor and starter. Check each leg of the power circuit
individually to be sure all three legs are 'hot'. Disconnect and lock out
electrical power and fix any bad connections that are found. If a 'dead' phase
leg is found on the supply side of the electrical service panel, contact an
electrician or electric company for assistance.
Throttle
lock (obsolete)
The page is here:
http://www.beautifuliron.com/gs_stc-88_throttle_stop.htm .
New Striker hammers do not need this modification! All of the smaller
hammers now have this operation built into the machine and the larger hammers
have always had this operating function. Striker is working with the factory to
create upgraded throttles for older hammers and will make these new controls
available to current hammer owners very soon. Some small hammers made by other
manufacturers still need this modification.
Previously the smaller Chinese hammers arrived from the factory with only a simple
throttle linkage and treadle lever. Anyone that has tried to operate one of
these hammers knows how awkward the throttle can be when transitioning between
the raise position and the strike position. Much of the movement of the treadle
is needed to simply lift the ram and then rotate the valving into the striking
position. But only a small amount of throttle is needed to rotate the valves
past the raise position and into the strike position.
My throttle stop design is a simple bracket and sliding bolt that is adjusted
to hold the throttle in the strike position with a small reciprocating motion of
the ram.
Striker
Tool Company has a large lineup of air hammers in different sizes along
with other tools and equipment, see their website at:
http://www.strikertools.com At left
are two pages from the most recent sale flyer. If I were to guess which of his
hammers are the most popular as far as number of sales per unit, I would guess
that it is the 55 and 88 pound hammers.
Ready-made work stands are also available from Striker Tool Co. for their
hammers. New hammer buyers can save a lot of time setting their new hammer
by buying the heavy pre-cast work stand is also offered by Striker Tool.
Striker hammers have heavier frames and anvil blocks.
The Striker hammer frame is larger, thicker, and heavier than its competitor. The
anvil block is much heavier than most other power hammers - translating into much more powerful blows to
the iron during forging. The striking force (hit energy) figures stated by
both vendors is identical, but they do not account for the actual differences
in striking power of these two different hammers. The hit energy figures are a
mathematical representation that was arrived at by comparing the speed and
distance of ram travel and weight of the ram. Therefore the hit energy figures
are not a true representation of actual forging capacity of the hammers.
A hammer of a given size will forge with more force against a
heavier anvil compared with a lighter anvil.
Striker hammers have larger open die gap. The open die
gap on the Striker (11 inches) is taller than the competitors' hammer (9-1/8
inches) and allows large tools to be used to forge heavy bars with more force
than a hammer with a shorter open die gap. This was a very important feature to me
because I forge large bars and use large (tall) hammer tooling, the larger
open die gap gives me the room to do this work.
For blacksmiths, air hammers are the only real choice
today. Whichever your preferences for hammer model or vendor, you really
can't go wrong when buying an air hammer from a reputable dealer. Air hammers
strike with approximately 2-1/2 to 3 times the force compared with a
mechanical hammer of the same ram weight. The larger open die gap on an air
hammer allows larger bars and special tooling to be used, tooling that could
not otherwise be used on mechanical hammers with their smaller open die gap.
While it is true that a Little Giant power hammer is great for drawing thin
bars such as knife makers work, the air hammer is designed for everything else
in which a large of amount of plastic manipulation of heavy bars is needed.
And today the price of a working air hammer is the lowest I have ever seen.
Now is the time to buy an air hammer- because they might not be so cheap in the future.
Latest update:
May 13, 2008
Page created February 02, 2004
Helpful
ideas for setting up a small air hammer.
