Simple Radius tool for Lathe

[Scott]

If you need a Lathe tool to cut a Radius, heres a simple way to make one, considering you also have a mill.

*Take a piece of Flat stock, like 1/2 x 1-1/4.
*Set up in mill vise, clamping on the 1/2" sides, at 10 or so- degree's(for cutting plastic)
*Mill the appropriate radius into the stock, if you want a 1/2" radius, use a 1" endmill and feed in .500" from the side and end of the stock, so what you end with is a quarter of a circle on the corner of the tool.
*You will have to relieve the un-relieved area to 10 or so degrees, using a grinder.
*Hone the cutting surface, removing the burrs and lightly hone the cutting edge as well.
*When cutting plastic, I dont harden the tool, but if material is Aluminum, I will either case harden mild steel using Casenite or make it from O-1 tool steel and through harden it.
*Some experimentation will produce excellent results, I generally run these tools slightly above center.
* If you feed this tool in from the Tailstock side it will cut an internal radius, if you feed it from the apron side it will cut an outside radius.
*I hope I have explained the concept well enough. The most important thing to remember when it comes to Tool Making is there are no rules.
*Make sure you have your hole bored in your part to Radius first.

Scott