Originally Posted by
klcarroll
@Johan;
No, ......The tool sold by Precision Reloading is not a "cross-pin style" tool.
I was unimpressed with ALL of the tools that featured either cross-pins or screws to create "bumps" in the bottom of the crimping groove. (....And this includes about a dozen attempts produced on my own lathe!)
The PR tool has a crimping groove that is cut on a piece of CNC machinery that is capable of "Spiral Interpolation". The grove is cut with a ball end mill, and the Spiral Interpolation is used to form four ascending ramps in the bottom of the groove, instead of the multiple "bumps" created by the cross pins in the older, simpler designs.
The result is a much smoother, positive, and more precise rolling surface.
I have yet to figure out a way to duplicate this series of cuts on my manual machinery.
Kent