Hi Team.
So I'm trying to make my own geometry on bullet swaging dies, and have had some requests locally from other bullet makers. (For copper jacketed bullets.) However I'm finding them incredibly difficult to make. I'm using 4140 and a custom form cutter I've had made, I drill in multiple operations on a manual lathe then finish with the form cutter by hand, but during polishing they are ending up too big internal D after running in with a custom form cutter.
I made the mistake of under-estimating just how much the part could grow whilst polishing. (Bore polished out to 0.2665 instead of 0.264.) The cutter was made at 0.264 hoping a gentle lap would suffice but I clearly not.
I'm thinking I need to have the cutter made at 0.262 and polish, however, I'm still feeling tooling marks in the bore too.
As you can imagine it is a very small bore to polish, 223/6.5mm etc. Anyone got any tips for polishing very small bores evenly??
I'm wondering if 4140 isn't the best material to use here, however I think it's important that the dies are either nitrided or hardened post machining. If anyone has seen a Wilson die, they are polished to a brilliant polish. I'm looking for a similar finish but don't know what metal they are made from.
Any tips or right-direction-pointing would be wonderful.
Thanks
Lplates.
So I'm trying to make my own geometry on bullet swaging dies, and have had some requests locally from other bullet makers. (For copper jacketed bullets.) However I'm finding them incredibly difficult to make. I'm using 4140 and a custom form cutter I've had made, I drill in multiple operations on a manual lathe then finish with the form cutter by hand, but during polishing they are ending up too big internal D after running in with a custom form cutter.
I made the mistake of under-estimating just how much the part could grow whilst polishing. (Bore polished out to 0.2665 instead of 0.264.) The cutter was made at 0.264 hoping a gentle lap would suffice but I clearly not.
I'm thinking I need to have the cutter made at 0.262 and polish, however, I'm still feeling tooling marks in the bore too.
As you can imagine it is a very small bore to polish, 223/6.5mm etc. Anyone got any tips for polishing very small bores evenly??
I'm wondering if 4140 isn't the best material to use here, however I think it's important that the dies are either nitrided or hardened post machining. If anyone has seen a Wilson die, they are polished to a brilliant polish. I'm looking for a similar finish but don't know what metal they are made from.
Any tips or right-direction-pointing would be wonderful.
Thanks
Lplates.