Steel sidedraft coal forge in my old shop.

Built of brick and steel plate as an experiment to see if a hoodless design would make the task of heating the iron more comfortable and convenient, this forge outperformed any other type of forge I have ever used in such dramatic fashion, that I will continue to build this style of forge in the future in preference over any other type. This was my third  forge and was built to make wrought ironwork gates and rail parts as well as tools, machine parts, and horseshoes.  The chimney drew smoke in all types of weather including heavy snow, heavy rain, and very windy days. And the chimney drew smoke so strongly that the smell of coal smoke had been permanently banished from the shop.

Based on a design offered by Dimitri Gerakaris in the Anvil's Ring. Internal dimensions of the chimney were based roughly on those found in the Anvil's Ring Vol. 7 #1 from March 1979. The inside of the chimney above the smoke box is 12" square. A large chimney cap kept rain and snow out. The hearth plate measuring 72" long by 40" wide, was made of 5/16ths steel plate reinforced with 1/4 x 2 inch angle iron. The hearth plate rested on the corbelled sides of the lower chimney at one end, and on two brick pedestals built over the front of the forge foundation at the other end. A tool rack was cast into the brick structure to hold hardies and hardie tools. Detachable tongs racks were made to hang from the edges of the hearth plate.

To see this forge as it looked after the first year, scroll further down this page.

Page updated April 08, 2007.

Building the forge

Forge construction took about 2 weeks. The weight of masonry requires the builder to add no more than about 2 to 3 feet per day. The temperature dropped during the second week as I was building the chimney and work slowed to 2 feet per day. Knock-down forms were assembled and installed inside the chimney in the appropriate locations to support the masonry while building the smoke chamber and smoke shelf inside the chimney. The forms were then broken apart and removed from inside the chimney. A smooth flue surface was desirable so mortar was simply rubbed against the sides of the knock-down forms and the bricks forced into it. With the wooden forms removed, the chimney needed no further work inside. No flue tiles were used in this forge due to problems trying to obtain them.

Knock-down forms used during construction. In the photo near right is the chimney under construction, this time showing the forms used to support the masonry while constructing the top half of the smoke chamber above the smoke shelf. The form helps during the application of mortar inside the chimney so to present a smooth inner chimney surface when finished. The form is not solid since it must be broken apart after construction. The lintel bar was also supported since it would damage the fresh mortar. The lintel bar is offset outwards slightly so that a sheet metal hood can be simply hooked over the edge of the lintel bar and hung from it.

At far right is a photo of the chimney a little later in construction after the brick has been built up over the wooden forms. The corbelled shelves built low on the sides (level with the bottom of the smoke entrance) will support the chimney end of the steel hearth. The hearth is made of 5/16 inch steel plate and is very heavy and will remain stationary, so the only place where it will be bolted down is to the masonry legs at the front of the forge. The hearth simply rests under its own weight along the corbeled sides of the chimney since it isn't likely to move if it is bumped or struck. A hardie rack was cast in place in the mortar near the base of the chimney. The space between the rails of the hardie rack fits my anvil tools, or about 1-1/8" between rails.

Positioning of the firepot in front of the chimney. At right is a closer view showing the position of the firepot near the chimney. The rear edge of the firepot is about 3 inches from entrance to the smoke hole of the chimney.   This was one of my experiments to find out if it was beneficial to place the firepot on a rotating separate plate to allow the firepot to change position for different jobs. I recommend that others don't bother with this arrangement. This was later found completely unnecessary as the firepot was never rotated. I now build coal forges with the firepot inset into the hearth, so the upper surface of the front and rear of the firepot is placed level with the surrounding hearth plate surface. Because room inside the shop was at a premium I was forced to locate the chimney as near to the wall as possible and so the smoke hole in the chimney was offset to compensate for firepot placement.

Refractory material protects brick nearest firepot. A refractory material (fireplace cement) was molded onto the front surface of the mortar nearest the fire to help protect it. The intense heat of the fire would quickly deteriorate the mortar otherwise.

Lintel bar. A lintel bar of angle iron supports the brick structure above the smoke entrance in the bottom of the chimney. The lintel bar is offset outward, so that a small sheet metal hood can be hung from the protruding edge of the lintel bar.

Hearth. The edges of the hearth are made of 1/4 x 2 inch flat steel, and are welded around the perimeter of the hearth to help keep fuel on the hearth. For a large forge like this, 2 inches was plenty high for keeping fuels on the hearth. For smaller forges, the height of this rim needs to be taller.

At left (Click on the thumbnail) is a view of the side of the hearth nearest the smith. At center of this photo the cutout area of the rim around the forge hearth, is clearly visible. The small hearth extension is visible (an extension of the hearth projecting out towards the smith) at the cutout area. And of great importance in this view is the reinforcement of the edge of the hearth in this area. It is no surprise that edge of the hearth is reinforced around its perimeter by the rim welded to it, but to remove a portion of the sides or rim anywhere along the hearth would leave it weak and prone to bending or collapse in that area. To strengthen this area the rim or side of the hearth is continued from underneath with a piece of 1/4 x 2 flat material welded to the underside of the hearth edge. The reinforcement overlaps the ends of the sides from underneath and gives maximum reinforcement to support this area as though no cutout existed. Also visible in the thumbnailed photo at left is the plumbing of the air blast pipe from the blower.

The blast air delivery piping is placed around the front of the forge and then down and backward into the hollow of the chimney where it then bends up and forward again to enter the tuyere pipe of the firepot. This is a no-no. Each bend of the air pipe restricts the flow of blast air. Had a hole been built into the lower-rear of the brick chimney structure, a single bend, or possibly a bend and a half would have directed air into back of the tuyere. There are a total of 5 bends between the blower and the tuyere pipe in this picture. Each bend makes it more difficult to get air into the fire.

Simple hanging tongs racks were fashioned from 1/4 x 1" flat stock which were made to hang from the sides of the hearth rim. The racks hung down well below the top edges of the hearth rim so that the ends of the jaws of the tongs were made lower than the hearth rim so that they didn't foul tooling or iron while working in the fire. At lower left is the smaller tongs rack near the anvil which kept the group of tongs most used or needed immediately.

Firing the forge for the first time. In the photo at left (Click on the thumbnail) a fire has been lit for the first time in this forge and a small bar is being heated. This was in the middle of December and the cold weather slowed the curing of the mortar so I didn't want to chance a large full size fire. Even with a small fire like this one, notice that the draught of the chimney is so strong that it actually bends the flame backwards towards the smoke hole. The edge of the rim which runs around the hearth, cutout to allow for level placement of the iron through the fire. In the picture at left the iron and tongs can be seen hanging over the edge of the forge nearest the smith. A small extension plate was welded to the edge of the hearth plate here at an angle slightly above horizontal, to give added work area to help support long pieces in the fire and to help keep fuel from falling off the edge. Also notice the group of fire bricks laid along the fire both in front of the fire and behind it inside the chimney. These bricks create a trough to help build up the height of the fuel in the fire and to help maintain the fire. Some of the older all-brick and mortar forges were built with a trough cast into the surface of the hearth to create this same effect permanently. To see what this effect is based on, look at the pictures on the Dows Blacksmith forge.

As the forge looked after a year of use.

These next pictures are of the forge finished and in use for some time. At right is a photo showing the forge and most of the shop area. Notice the large size of the hearth plate. Coal was simply dumped in a pile on the hearth with as much as 100 lbs. of coal on the hearth when a new bag of coal was added. The hearth was large enough to support all of the coal with plenty of room left over for placing tooling in easy reach, and for small bars or objects to cool safely before quenching. Fire bricks are placed around the perimeter of the firepot to help build the height of the fire. Free hanging tongs racks were made and hung on the side of the forge hearth for tongs used most often, and another hung at the front of the hearth for tongs needed less often than those nearest the smith. Tongs racks were hung low enough to allow the jaws of the tongs to remain below the hearth and out of the way to avoid snagging tooling and work being moved back and forth around the fire. The racks hang free and can be quickly removed when needed. Notice the rim around the forge helps keep fuels on the hearth instead of falling off the far edges of the hearth. Anvil, water barrel, and vise are all located nearby. At far left is the hand cranked blower.

A piece of pipe or other object placed across the opening of the hearth rim near the fire kept fuels from falling off the hearth during use. Seen here in the working photos at left are some large scrolls being heated. The weight of the scrolls rests on the pipe placed across the opening in the hearth edge, but if it caused any obstruction to placement of objects in the fire, the pipe could be removed in a second. The small extension at this opening in the hearth edge, was slightly inclined to help fuels stay on the hearth when the pipe or other objects couldn't be used to help contain fuels from the fire. As can be seen in these photos, smoke entering the side draft chimney literally lays over sideways to enter the bottom half of the entrance in the chimney. This demonstrates the strength of the draw acting on the smoke and forcing it into the chimney.

Look at the inside of the chimney and the reader will notice the cinders have been allowed to build up into a sloped pile. This poses no problem and is actually desirable. The cinders or fines protect the bottom surface of the inside of the masonry from direct flames of the fire. Notice there are about 6 firebricks in front of the fire, these help the smith to build height of the coal to aid in constant creation of new coke for the fire. But hidden beneath the fuels between the fire and the entrance of the chimney, is another pair of firebricks. Again these firebricks help aid in adding height to the fire for the production of new coke. As the forge is placed into regular use, cinders and fines will fill the inside the chimney behind the firebricks and slowly build up a sloped pile. Periodically some cinders will need to be removed (about once a year) and disposed of. But the cinder bed inside the chimney is also helpful in adding a natural bed or height above the fire to aid in moving fuels to the fire just as the double row of firebricks in front of the fire.

At left are two photos of the view the blacksmith has when standing at the anvil. Tongs racks are out of the way, yet close enough to allow quick access. Although photo quality is poor, the reader can just make out the piece of pipe laying across the cutout area of rim of the hearth near the smith. The pipe helps keep fuels on the hearth when long bars do not need to be left hanging off the edge of the hearth for heating.

At left is the view of the shop and forge when looking into the building. Because of the tiny size of this shop ( 11' x 16) space was at a premium. Behind the photographer and to his left and right were a drill press and a Little Giant 25-pound power hammer.

Hardie racks were cast into the brick work on the side of the lower section of the chimney during construction. Hammer racks were cast into the rear of the brick structure to hold lesser used hammer tools. Again the pipe laying across the cutout area of the rim of the forge hearth is visible here in place to help hold fuels on the hearth. The pipe is not necessary, but is a simple and quick convenience.

Not visible here also, was a wood-burning stove for heat. The stove was located to the left of the forge in this photo and about 6 feet away from the smith.

My old steel fabricated forge.

At left and below left, are photos of my first successful forge built of angle iron and sheet metal. A Centaur Vulcan firepot and a British Alcosa hand-cranked blower, both bought new, from Centaur Forge are installed on this forge. Firebrick lines the rear wall of the hood right up to the bottom of the smoke entrance of the chimney flue. The forge pictured here worked well enough that I used it for 6 years. It was a of a conventional style of fabricated forge with a half hood. Similar in design to modern fabricated forges which can be purchased from Centaur Forge. A tong rack was welded to the front to support some of the tongs I used for gate and blacksmith work. Firebrick lined the rear wall of the hood up to just below the chimney pipe. Smoke actually is attracted to brick structures and will hug this wall till exiting to the chimney. The top of the fire brick acted as a smoke shelf to help control back drafts from pushing smoke back down the chimney on windy days, which until I started using this fire brick back I had problems with a smoky chimney. The chimney pipe is a custom made sheet metal pipe made at a local fabrication shop. A new hand cranked blower was fastened to an arm extending from the back of the forge. The firepot was a Centaur Vulcan which at that time cost about $85. (They are about double that in price now I think.) Firebrick  was then built up around the fire pot to help create a deeper fire and make use of gravity when tending the fire. The forge is long gone now but it measured about 40 inches side to side, and about 60 inches from front of tongs rack to rear of chimney. It stood about 40 inches tall. I used this forge to make everything from wrought iron gates to draft horse shoes. All of the tongs seen in these photos are made by me as well.

The firebrick lining the back of the hood wasn't in my original plan. But over time as I learned to use the forge for more complex forgings and repairs, the brick wall in the rear of the chimney and the bricks around the fire were added. Within a year after building the steel forge, firebrick lined the rear wall of the hood clear to the chimney pipe as seen in the first photo above. The firebricks were often needed for small welding jobs so they tended to disappear and reappear at different times in these photos.

Note the convenient position of the blower which is mounted so that the crank does not come in line with the path that long bars take when placed in the fire. Long bars could thus be heated with this forge without fouling them with the hand crank of the blower.

One problem encountered with this forge is height of the tongs racks. I found through experience that tongs should always be hung so that the jaws are below the level of the forge hearth so that they don't interfere with or foul the bars or objects that are placed in the fire. This is especially a problem when working on large scrolls and parts for gates and when making repairs to large awkward machine parts.

My newest semi-portable steel forge

Here is my latest all steel semi-portable side draft shop forge. The side draft hood is fabricated of sheet metal and angle iron welded together. The dimensions for the inside of the hood follow the internal dimensions of the sidedraft forge designed by Dimitri Gerakaris in the Anvil's Ring issue March 1979 and are similar to the dimensions used in the brick chimney seen above. To see more on this forge go to the Steel Sidedraft Forge page here: http://www.beautifuliron.com/mysteel.htm .

The hearth plate was cut out of the remains of the hearth plate of the brick and steel forge (photos at top of this page) when I moved to my new shop. While I plan to build a large forge again in the future for my ornamental ironwork, a good sidedraft forge was needed in the interim which could be transported to use in the field as well as setup permanently in a shop setting. The hearth measures 32" wide by 36 inches long, and stands 31-1/2" tall or about 1" below the knuckles of the hand when standing beside it. The firepot is a Centaur Vulcan saved out of the brick forge above and the blower is the same Alcosa seen in the photos of the brick forge above on this page. The firepot measures roughly 13-1/2" wide by 12-1/2" long (the longer dimension being across the width of the forge or in line with the steel bar seen placed across the forge  in the photo at left). The distance between side edges of hearth and edges of firepot is 9". The rear edge of the firepot is 7-3/4" from the rear of the hearth and the front edge is 15-3/4" from the front of the hearth.

Latest update 08 April 2007.

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Page created around November 1999.