a bit long winded.. sorry
when I did mine,( I actually did two )
I started by figuring out what material I was going to use for blocks. aluminum in my case. I was taking a machining class at the Vo-Tech , so I faced the surfaces on the Big Acer mill they had. then matched the blocks and drilled them for 2, long metal dowels, so they could just slide back and forth and stay in register.
I used a Machinery's handbook, to figure out the shrink rate of the lead against the expansion rate of the blocks. this determined what size I'd need to turn the blank. if I remember right it worked out to -0.005-0.006. so for my gun the blank was 0.334 to end up with a .340 ball from aluminum blocks.
I roughed in the mild steel cherry on the lathe and following the advice from Fento in Australia, I lathe filed it.. trusting , as he said, My eyes, balance and feel. The blank ended up only 0.0003- 0.0005 out of round according to my Brother in-law. He couldn't believe I'd try it and wanted to measure it with HIS micrometer. < a new box of Hornady lead balls were way worse, when we measured them!
>
btw, after my instructor heard me talking about the project he asked to measure one of the blanks!! I automatically got an A in the class and had carte blanche to do what I wanted in his shop!!
using the extension I had left on the shank, I held it in the vise. beforehand, i had purchased a new/small triangular file and ground a safe edge. using this I hand filed
the teeth to the cutter using my magna-visor to keep a good focus on things,. I had blacked it with a sharpie and using the safe side, was able to keep the flutes fairly straight sided and also back cut the next one over. I made the teeth on a slight angle and made sure at least one tooth went across the bottom arc/surface of the cherry. using the blacking I was able to keep a thin edge on each flute.
out came the lil propane torch and a can of kasenite. after I cut some of the extension off the part, I heated dipped and quenched the cherry three times. well, just because??
after this, back to the magna-visor and a bright spot light . Using a hard arkansas stone 'stick', I whetted the edges of the flutes. just making the blacking barely disappear as I angled toward the cutting surfaces. <Wish I had waited to cut the extension
)
I really wish I had a mill at this time, but I used my lil benchtop Craftsman drill press. I did it all wrong at this point! ( or maybe from the start!
)I brought the table up and established the how deep into the block it would go. I cobbled up a set of clamps/rails using some scrap metal and a pair of C-clamps. I started the press and working slowly, I started to close the mould halves.
lots of stopping to spread the blocks, clear chips and re-lube. OH, Found out that liquid wrench makes a great cutting lube for aluminum! My instructor had kinda 'hinted' I may want a can near when I did the cutting. Pretty soon I had the blocks closed and the cavity cut. Maybe not the best job ever?? but hey, I did it myself! To finish of the blocks they went back to class and I trimmed the top of the blocks down to the top of the ball/shank area. I used a square and a sharp scribe, to cut a couple of vent lines across the face of the blocks. these were really light and after a lot of use have worn even thinner.
made up a Hokey set of handles and added a cut off plate. Not pretty but I went to casting!! Fired a whole lot of those balls at various shoots! later in a trade/barter, I gave up a lil 28 gauge Belgian smooth bore for a guys project and in return got a lee mould in 0.340 and a couple of other things if I remember right?
My Bud is happy as a clam, shooting his old Numrich .31 cal barrel, which takes a patched .295 ball. His mould I made the same way as above. just didn't take as long to get the mould halves closed, when I came time to cut the cavity!
Hope this explains a lil of what I did??
When I get a chance to find a couple of things, I'll get a pic of the mould, cherry ( or a blank ) and a few of the castings!
Respect Always
Metalshaper/Jonathan