Thanks for sharing an excellent point about how precise these molds needed to be. IMO, i think that may be another needed step once the pellets are swaged. If in case the pellet swaging molds do not provide a consistent headsized to pellet specifications. It's actually ideal to have a head sizer, that way we have some control over the finished pellet. it's also not bad for 5 secs per pellet to be sized. ha, I haven't thought about that at all...that's brilliant, mate!
Quote from: ken47 on July 19, 2018, 07:32:46 AMGuys hold on for a week, .22 cal (head 5.52mm) 18.52 grain 5 cavity mould is under development. Its for my own use I have a local machine shop assisting me to make it. 0.01mm tolerance is difficult to maintain on a manual milling center so they are using a Japanese 3 axis CNC for it. I ran into the incredibly precise tolerance when making my own pellet head sizer with my small benchtop lathe and a small milling machine. With my lathe I couldn't bore a hole within a couple .01mm using a small boring bar so I started with a piece of O1 tool steel and drilled a 4 mm hole in the center. Then I reamed the 4mm hole with a home made piloted "D' reamer that created a stepped ream with an undersized "sizing ring like this sketch........ The sizing ring in the die was then lapped till a pellet head pushed through the sizing ring had the size I wanted (rather long/tedious process). Here is the result showing a few versions of the sizer and various "D" reamer designs I tried ...........To use I first drop an unsized CPL into the die................The "ram" is inserted in the die............Then I insert the "ram" to push the pellet head through the sizing ring and expand the pellet skirt while making it perfectly round. The ram is at a fixed position in the holder so only the pellet head gets sized..........Then the sized head is pushed back out of the die.................The sizing of each pellet takes about 5 seconds while watching YouTube airgun, machining, whatever videos.......... Here are some 1250 count boxes of CPLs that were headsized watching videos and later sorted by weight...........The reason I'm mentioning my CPL pellet head sizing process is simply because I found it extremely difficult to get a pellet head of a specific size till I added a "sizing ring" to the die that could be lapped to the proper size. I'm wondering if a person could make a "5 pellet mold" (mould indicates casting to me) with consistent pellet heads with a 0.01mm tolerance, even with the larger .22 cal. I'm thinking that a .22 cal swaging die might give 0.01mm accuracy, however that would indicate a single die with a complicated high pressure press.Anywhoo.........even the "big pellet swagers" (like JSB & H&N) have issues maintaining a consistent .177 pellet head and this JSB Exact pellet sort shows a .10mm variation with most varying about .04mm straight from the tins.........
Guys hold on for a week, .22 cal (head 5.52mm) 18.52 grain 5 cavity mould is under development. Its for my own use I have a local machine shop assisting me to make it. 0.01mm tolerance is difficult to maintain on a manual milling center so they are using a Japanese 3 axis CNC for it.
Ken, I am surprised that you need to go to a .2 mm diameter ball cutter. What is the smallest caliber pellet you are trying to make with this? I would have thought that you could interpret a .22 or larger caliber pellet design, such that it would be functionally equivalent when made using a .5 or even 1 mm diameter ball cutter.
I am not too worried about distortion, we can ream with the cutter once again.