I was asked to build a round table top for a steel outdoor table which is now used to work puzzles in an enclosed patio. The problem was that the table had a steel ridge around the edge. Since plywood is not 1/4", I was able to use it and it barely rises above the edge.
To make the circle, I built a router trammel, similar to the one found in Woodsmith magazine using a 2" wide Al ruler. I changed the center point to a block of wood with a 1" dowel that can be attached to the work service with double stick tape. No need to drill holes in work piece. Also, I routed a test piece to be sure that the top would fit the table.
The next problem was that the steel table had a center hole to hole an umbrella. You can see this in the pictures. To keep the top flat, I built a jig that would allow me to route a recess in the bottom of the round top. Was not sure how this was going to work in such a thin piece, but it does what I wanted.
![Machine tool Machine Tool Wood Table]()
Completed Router Trammel
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Center blocks for Router Trammel
![Ruler Tool Calipers Measuring instrument]()
Center block of Router Trammel attached to Al ruler. This is used to determine the finished radius.
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Test piece to be sure circle was the correct diameter of table.
![Product Table Coffee table Circle Outdoor table]()
Steel table used to work puzzles. Wanted a top made of wood.
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Center hub in table top. Had to come up with way to make new top to lay flat.
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Jig used to route out material so table top would lay flat on on steel table. Used double stick tape to hold jig in place.
![Table Coffee table Wood Furniture Plywood]()
Finished piece of plywood.
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Finished table. Used three coats of Arm R Seal Urethane.
To make the circle, I built a router trammel, similar to the one found in Woodsmith magazine using a 2" wide Al ruler. I changed the center point to a block of wood with a 1" dowel that can be attached to the work service with double stick tape. No need to drill holes in work piece. Also, I routed a test piece to be sure that the top would fit the table.
The next problem was that the steel table had a center hole to hole an umbrella. You can see this in the pictures. To keep the top flat, I built a jig that would allow me to route a recess in the bottom of the round top. Was not sure how this was going to work in such a thin piece, but it does what I wanted.
Completed Router Trammel
Center blocks for Router Trammel
Center block of Router Trammel attached to Al ruler. This is used to determine the finished radius.
Test piece to be sure circle was the correct diameter of table.
Steel table used to work puzzles. Wanted a top made of wood.
Center hub in table top. Had to come up with way to make new top to lay flat.
Jig used to route out material so table top would lay flat on on steel table. Used double stick tape to hold jig in place.
Finished piece of plywood.
Finished table. Used three coats of Arm R Seal Urethane.
