Info needed on possible method of creating uniform round bottom to strengthen vee gravers

[AllenClapp]

After creating heels on vee gravers, I like to round off the sharp bottom heel edge to limit chipping. However, I often screw it up when rounding by hand and end up changing the heel angle. I can uniformly make a flat spot on the bottom of the vee heel by gently swiping the graver over a stationary diamond wheel while in my Apex fixture, but that still leaves slight edges on the heel because the change is not rounded. Then I had an AHA moment. Why not cut a round line in a cast iron plate with a 0.8 mm [or so] GRS step graver, dust the round bottomed groove with diamond powder, lift the Apex fixture holding the graver erect at the heel angle up, align the diamond-dusted plate under the graver, and then pull the plate away from the graver point to create a uniformly rounded heel at the correct heel angle? When I looked online, I saw lots of types of iron and some types of cast iron plate. I know that many engravers use diamond dust on GRS cast iron plates, but I am ignorant as to what types of iron will allow the diamond dust to impregnate it and work as described. If you have had experience with creating a diamond plate, what types of iron or cast iron plate do you think would work well in this case?

 

[rweigel]

Hi Allen,
I never tried it with a pre-cut groove, which is BTW a brilliant idea, but I polished gravers held in Lindsay-like templates both on mild steel and extra-hard brass plates impregnated with 0.5 um diamond. As long as one pulls away from the cutting edge, it worked fine. The brass plate gave a slightly higher polish and was more resistant to being cut by the graver accidentally, the steel plate removed more material from the graver per pull. I still use the mild steel plate to put the final polish on my woodworking chisels. So, your idea seems sound and should work. Mild steel could be scribed to make the groove, 0.8mm actually seems a big size for the groove.

I round the apex of my carbide V Gravers with the flat face of a felt wheel that I impregnated with 0.5 um diamond paste. That works slow enough to be controllable with the flex shaft. Since I do this, broken points of carbide gravers seem a story from a distant past. I also polish/round the back ends of the heel, resulting in very bright cuts.

I‘m currently designing me a new minihone that could accomodate not only my established 50mm copper discs, but also dental rubber diamond polishing wheels of 22 and 26 mm. That would allow me to polish away the sharp apex and also polish/round the heels of the gravers at exact angles. It will also contain fixtures to grind the shape of round, onglet and lozenge gravers and heel them at the correct angles. Completion is planned for end of 2025. Once it works, I will publish it here.

Cheers

Ralf