FORM TOOLS FOR BRASS

[CHARLES lipscombeParticipant @charleslipscombe16059]

I don't know if I have just re-invented the wheel or come up with an idea that others might not have thought of.

I needed to make a number of 16mm balls in brass and doubted my skills on a grinder to make a good job of the form tool. In the end I got a flat piece of tool steel and simply cut a half-circle in it of the right diameter, using a solid carbide end mill.

This worked very well. The end mill was not a high-end specification one, it was a low cost item from Jenny at JB Cutting Tools (usual disclaimer)

Chas

[CHARLES lipscombeParticipant @charleslipscombe16059]

[egaParticipant @ega]

Good idea but how did you provide front rake on the tool?

A "Conecut" drill can be used to make a tapered hole which is then cut back to produce a semicircular tool.

[Neil WyattModerator @neilwyatt]

Dang, I posted a reply earlier but…

My approach is to drill a slightly angled hole in a bit of gauge plate, then trim off the excess. See MEW 276!

Neil

[CHARLES lipscombeParticipant @charleslipscombe16059]

I just placed a small piece of scrap under the front of the toolbit to raise the front and provide what looked like a suitable amount of rake. To the best of my knowledge the exact rake is not critical in this application. I used a spray can of WD40 to lubricate and cool the work in progress.

Regards,Chas

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