Build a Slabroller
The instructions here are taken from the book Getting into Pots: A Basic Pottery Manual
by George and Nancy Weltlaufer. Originally published in 1975 by Prentice Hall, this book is now out of print. The instructions were reprinted in Cermaics Monthly in February 1977.
These instructions are for personal information purposes only. Do not reproduce these instructions for sale or resale.
Draw the Guide Lines
- 2 sets of appliance (refrigerator) casters
- �" sheet plywood; 32x48 for the bottom board
- �" sheet plywood; 24x36 for the top board
- 4 cable clamps
- 4 eye bolts
- 2 angle iron pieces; 27" long
- 2 bronze bushings or pillow block bearings
- 1 steel rod; 35 x 3/8
- 2 steel cables; 6' x1/8"
- 1 2" steel pipe; 24" long, threaded
- 2 end caps
- 24 sheet metal screws
- 1 steel bolt or nail
- 2 blocks of wood; 2x4x6
- 2 sheets 1/8" thick hardboard; 24x36, used to alter slab thickness
With a pencil draw centerlines on the bottom board, separating the board into four equal rectangles. Then, draw a 4" margin along the two long sides of the bottom board. You now have a bottom board divided into quarters with margins on either side.
Place the Casters
Set the caster in place before attaching them. Set the first casters 2" from the outside margin inn one direction and 2" from the centerline in the other direction.
Set the next two casters on the long center axis, 6" back from the short center axis. This will give stability to the top board when it is rolling.
Set the next two casters on the long center axis, 2" from the outside edge of the bottom board.
Once you have set them in place, drill the bottom board and screw down the casters. Be very careful to get the casters exactly square, parallel and perpendicular to the edges of the bottom board and centerlines.
Assemble the Roller
Have your 2" pipe cut and the ends threaded. Be sure the pipe surface doesn't get scored or deformed in the threading process. Screw on the end-caps; then have a 3/8" hole drilled for you. The hole must be exactly on the center axis of the pipe. Do not drill the end-cap on center and assume that this win fall on the pipe's center axis. This is best done on a lathe. This is the most important step. It's worth paying someone else to do it accurately. Otherwise, when you use the slab roller, you will get an up and down washboard-like surface on your clay, and this uneven thickness is likely to cause warping.
Slide the 3/8" steel rod through the roller; let 2" extend from the opposite end-cap. You will have 2" of rod on one end (to go through the bearing) and 4" or more on the other end to go through the bearing and to have a handle (we use vice-grips) attached to it.
Drill a hole at either end of the pipe which passes through the center of the roller pipe and the center of the steel rod. This hole is for the steel bolt or nail that will keep the roller pipe and its center rod connected to each other. They could be welded together if convenient, but the nail holds them fine.
Drill another set or holes for attaching the cables later on. These should be straight across from each other and �" in from the edge of each end cap.
Attach the Roller the Bottom Board
Set the 2 x 4 x 6 blocks of wood on the outside edges of the bottom board at the centerline to support the roller assembly on either side, like a bridge.
Slide one bearing onto each end of the steel rod extending from the roller pipe. Set the bearings on top of the 2x4x6 blocks. Align them so that the roller is exactly perpendicular to the long edges of the bottom board.
Adjust the distance between the bottom of the roller and the top of the rolling board. This distance will limit the maximum thickness of your rolled slab. We use a �" rolling board, and our roller mounting is 2�" high, giving us a �" maximum thickness for clay slabs. To make thinner slabs one or more sheets of the 1/8" Masonite is then placed on top of the rolling board to increase its thickness and decrease the space the clay rolls through.
Attachment of the Angle Iron Brace to the Top Rolling Board
Drill two �" holes in both angle iron braces, each one �" in from either end. When the angle iron braces are attached to the top rolling board, these holes will be in the portion that extends beyond the edge of the board, for the purpose of attaching four screw eyes. Now drill several smaller holes in the angle iron, evenly spaced between the two larger holes, for the purpose of attaching the angle iron to the board.
Hold the angle iron braces on each end of the top rolling board. They should be flush with the bottom edge and extend 1�" on either side. Use sheet metal screws through the small holes that you drilled to attach the angle iron to the top rolling board. Then put the four screw eyes into the four larger holes on the ends of each brace.
You may need to "shim" the top side if the angle iron. If there is a space between the angle iron and the top of the plywood when the angle iron is flush with the bottom edge, fill the space with a narrow strip of wood.
Mounting and Adjusting the Cable
Stand in front of your partially constructed slab roller with the steel pipe roller assembly perpendicular to you. Roll the top board under the pipe (and over the casters) pushing it almost as far to your right as you can. The left-hand end of the top board should stop two inches from the center roller.
Fold one of the cables in half to determine its center point. Do not crease the cable. Open up the cable at this point, and slide a sheet metal screw through the middle of the cable - an equal number of metal strands should be on either side of the screw. Repeat this with the second cable. Screw the midpoint of each cable to the roller. The holes were created in an earlier step.
You now have the roller with the cables resting on top of it - the screws attaching the cables to the roller are on top. The top rolling board has been slid to the right so that its left edge is 23" from the center roller.
Take the left-hand end of the cable nearest you and feed it under the roller and out the other side. Pull it through all the way to the right side, and put it through the screw eye on the right end of the top rolling board. Clamp it loosely. Repeat the process on the other side - still working from the short side of the rolling board, under the roller, and out to the long side of the board. Both screw eyes on the same end (originally the right end as you faced the slab roller) will now have cables attached to them.
Now take the right end of the cable and feed it under the roller from right to left. Repeat this twice more, making three clockwise cable rotations around the roller. Then extend the remaining length of cable to the left, just a few inches, through the screw eye on the left end of the top rolling board, and clamp it loosely. Repeat the procedure on the other side of the slab roller.
Attach a vice-grip, as a handle, to the rod extending from the steel roller. Carefully roll the center rod, which will drive the top board now that the cables are attached. Rotate clockwise as far as it will go to see that the cables are long enough to allow you full use of the total length of the top board. After you have checked this in both directions, clamp the cable clamps down tightly. Finer adjustments in tightness of the cable can be made at any time by screwing the screw eyes in or out a few rotations. Tightening the screw eye bolts so that the top board runs true makes the final adjustment.