what does a mold cherry look like

[runfiverun]

Tom [accurate] does it different.
I believe Dan at Mountain Molds does it similar to Accurate.

NOE does it the CNC way.
Hm-2 also does or did also, I watched them cut some of the first mold they cut for each new design. [and tested some of the proto-type molds before the final features were decided on]
and I believe Arsenal molds are cut on a CNC also.

[Cosmic_Charlie]

If I would have had more patience for math as a school boy I would have liked machinist work. The ultimate practical problem solving vocation.

[Thumbcocker]

The Foxfire book on flintlock rifles had pictures of cherries designed to be used with a hand brace with soft iron or soapstone blocks.

[W.R.Buchanan]

Travis: Several ways to do this. You've seen most here.

The method being used by outfits like NOE and MP is called Circular Interpolation. This is where a cutter moves thru a circular path by working the X and Y axis' of the machine against each other to generate a circle or in the case of moulds half a circle.

In the case of moulds, the mould halves are machined separately and one half of each bullet cavity is cut into each side of the mould blocks. The real trick is getting both halves to line up perfectly and this obviously requires some very precise machining. I am not capable of this in my shop, er maybe I am, but just don't want to.

The cutter for the mould cavity looks exactly like the end product but slightly smaller. This allows mould cavities of different diameters to be machined with the same cutter by simply altering the program. This is necessary as the "Shrink Rate" of the metal used to make the boolits varies with the alloy. Harder alloy shrinks less as it cools and this must be accounted for.

An example of this was a RCBS .45-300FNGC mould I had which dropped Boolits made from Wheel Weights at .457. This was useless to me as I needed .459-460 to shoot right. RCBS had designed the moulds around the shrink rate of Linotype alloy which shrinks less and therefore delivered boolits of the correct size,,, Except nobody casts .45 cal boolits out of Linotype! I bitched to the head duck at RCBS and they made me a new mould that dropped linotype at .463-4 and wheel weight material at .460-1., and this worked perfectly.

All they had to do was alter the program slightly (change the dia of the cutter in the program) to make bigger cavities.

This is why the CNC method is being used now, it is very flexible. Once the position of the cavities in the blocks is dialed in,,, they all come out the same.

Randy