Saw part duplication

[August 9, 2015]

This simple project involved the duplication of a missing part. An acquaintance recently purchased a radial arm saw, with unfortunately a couple of missing pieces. The missing piece was the small clamp shown to the left - the clamp on the left of the photo is an original, and the clamp on the right is the duplicate I built.

I couldn't find a long enough thumb screw at the local big box store, so I made one from a 5/16"-18 x 2-1/2" bolt. I heated up the bolt head with a MAPP torch, and then hammered it flat (followed by some grinding to shape the part). I turned the clamp pad on the lathe, and also turned the end of the bolt to fit the hole in the pad.

Initially I tried to turn the end of the bolt so that it would "snap fit" into the hole in the pad, but this did not work - when I tried to press it on it the pad just sheared off the "bulb" on the end. I finally ended up just turning a longer piece on the end of the bolt to fit the hole in the pad, and then after fitting the pad, peened the end to hold the pad in place.

I also purchased a 5/16"-18 square nut, but it didn't have the required flat profile I needed, so I just milled a piece of cold rolled steel to size and drill and tapped it for 5/15"-18.

[See photos below.] The clamp body was made from 18 gage steel sheet. The steel was heated with a MAPP torch and bent over a piece of steel milled to size as a forming tool. With some heating, hammering, and clamping in a vise, the basic U-shape was formed, and then cut to size by rough sawing followed by milling. The other required cut-outs were made by scribing the required cuts using the original clamp as a pattern, and then cutting out the pieces on the mill with a slitting saw. As a final step, the piece was cleaned, de-greased, and spray painted black.

Forming clamp body from 18 gage steel.

Milling slot for nut.

Finishign shape with slitting saw.

Before final assembly, the thumb end of the screw was also spray painted black. The parts were then assembled and the clamp pad was peened in place.