This video shows how the receiver threads in an action are trued up and squared using multiple taps to minimize the amount of material removed while still getting an accurate fit.
NOTES:
OK, for those who wanted to see how I recut action threads, this is it in a nutshell. It's a disgustingly simple thing once you see it done and it works VERY WELL! The tech is based on what some of the reamer makers are offering with the tap and mandrel being made as one unit. The big improvement with this system is that you do not have to hog out .010 of an inch out of the receiver. You only take what you need to clean it up. Only about 80% of the thread needs to be cleaned up to make the barrel screw in straight and square. Remember that doing this is pointless if the receiver face is not trued and even more pointless if the threads on your barrel are under sized. You need a friction fit between the barrel and receiver threads or the threads will cock to one side or the other and cause misalignment. A square shoulder will NOT correct this. Trust me on that I have tried it MANY times. The down side to this tech is the cost of the tooling.
It would be to long of a video to show the complete process of going from one tap to the next. But once you do and watch it progressively clean up one specific area more and more you begin to get an idea of how controlled and precise it actually is to do it this way. Plus when you do it in a cats head or a chuck using a boring bar you have slop in your headstock, flex in the apron, flex in the cats head, flex in the boring bar and the cutter dives and pushes away in hard and soft areas. This is a VERY rigid and precise way of doing it. Plus, as long as your bar fits the action tight, it's almost 100% idiot proof.
Over time I have found that 18mm, 1144 Stressproof is the simplest material to make mandrels out of. I was using 18mm 4140 pre-hard but it just isn't necessary. Plus, 4140 pre-hard likes to walk a bit when you turn or grind it. The first ones I did I also ground in the Cuttermaster. 18mm is about .7085 inches and Remington raceways range from about .704 and up but never as much as .7085. So really, you only have to remove no more than .016 inch from a piece of 18mm material to bring it to size and 1144 never walks when you turn or grind it in such small increments. I cut the mandrels in the lathe now. If my finish cut is a little to big or a little to small I put the bar into stock until I get an action that size and simply cut another. I have just over a dozen different ones now in what amounted to .0005 inch increments and haven't had to make one in a couple of years.
30 мар 2022
