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2 Piece Point Form Die… Feasible?
Warning: Long post
Ok so I posted some pics of this already in another thread but I figured I’d post a new thread to get some thoughts on the subject. So I’ve been thinking about trying to make a 2 piece PF die. The die would be composed of 2 parts, the main body and the ogive/threaded piece. So from a manufacturing standpoint, making the main body section would be simply. It’s basically a through hole, honed to the exact diameter you wish. It would also have 3 clearance holes that are c-bored for 8-32 SHCS. The bottom face that mates up to the ogive piece would be ground after heat treat to ensure that the bore and face are perfectly perpendicular. And of course the bore would be honed after heat treat too. Here is a pic of the main body.
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Next would be the ogive part. It would be cut with a form tool and finished with a boring bar. Polishing the ogive will be much easier with the access you’d have. To get the ogive just right and meet up precisely with the main body diameter, I plan on boring a short section, maybe .03-.05 long just before the ogive starts, to make sure my cutter is cutting at the correct diamter, as it’s very difficult to measure the diameter at the beigining of a radius. Then once satisfied the ogive is correct, the .03 to .05 section will be faced off, leaving maybe .003 for a finish grind after heat treat to ensure perfect perpendicularity. Drill and tap 3 8-32 holes. Here’s a pic of the lower ogive/threaded section.
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So, then all that has to be done is align the upper and lower half. I’ll take a gage pin that is a snug slip fit in the main body and turn the profile of The ogive on one end. Then screw the bottom section into the press, and insert the alignment pin in the main body and line up the bolt holes and carefully tighten them down while the pin remains in the main body locating the 2 halves.
So a couple of my thoughts/questions:
If a system like this works, using the main body and switching the ogive section would be super simple, and possibly cost effective.
From a manufacturing standpoint, one may think that this process is far more complicated. I can’t answer that. But, I do know that with the complexity and skill of manufacturing a good PF broken down into these operations I feel that guys that don’t do it day in and day out could make good PF dies. As far as high volume manufacturing, I feel this method would allow for much faster and easier production.
Also, could the main body of the PF die realistically be used for the core seat process?? Obviously you’d need a different threaded base piece.
Thanks for taking the time to read this long post. I’m not trying to reinvent the wheel, just trying to address some of the hardships with making these pesky PF dies. Let me know your thoughts. Thanks!