05-26-2016, 04:27 PM
(05-25-2016, 06:25 AM)PixMan Wrote: Looks like a serious challenge. From the design, it appears the V grooves are the most critical feature in that you would have to get the center distance and depths VERY close to perfect to have it register consistently.
I do have a grinding wheel setup (wheel mounted on arbor and dressed) that's a 90º shape. We could plunge one to a given depth, crank the table over by the exact distance of center to center of the V and plunge the second. That would be far faster than four setups on V blocks, and more consistent. I imagine it's best to do that final grind on a multiple of them.
That would be a similar set-up to how I made Charpie test coupons out of chain, but there was only one V groove. In contrast the specs on the V groove included a radius on the bottom with a +/- tolerance of .001". We used a very fine grain wheel with a strong bond but I cannot remember their specs. For our purpose it created the radius on the wheel as we ground the coupon. In other words we used wheel breakdown to shape the wheel.
Personally I'd mill the V grooves with a form cutter, HT, then finish grind with a form wheel. I don't think the grooves need to be "exactly" the same from holder to holder, but CL to CL and depth need to be very close between the grooves of an individual holder. I'd grind them with semi-finish passes followed by a redressing and a single finish pass
BTW, that's probably the best QC tool holder system every designed. Used correctly it will repeat closer than any other type.