I was rebarreling my old shot-out Mauser sporter in .257 Roberts and set up the shank length for the required .002 crush fit. I got to thinking about take down barrels on M-98's and wondered how they were fit up. Obviously you cannot hand tighten them to a crush fit. I hoped some of our gunsmiths could tell me what procedure they use for takedown fitting. Lee.

I have heard the term crush fit all my life and it is nonsense.
Originally they were fitted and torqued to what seems like whatever the assembler thought enough. Because they vary all over the place. Don't forget that military Mauser barrels do not bear on the receiver face; only the inner ring.
Then the markings were placed on them. Unlike US barrels which have extractor slots and are precisely made with a torque and removal setting. Which I have forgot.
Required .002? Required by whom? No one.
So, you tighten them until they are tight. For me that means with a 4 foot bar with moderate force.

OK Tom, I was taught to make the shank .002 longer than the measurement from the receiver face to the inner ring in order to keep the barrel flange from making contact with the front of the receiver and then getting the proper fit without having a noticible gap. Crush may not be the correct term, but as you well know, threads stretch under torque which changes clearances.
All that aside, in regards to the initial question, since you cannot torque a takedown barrel into the receiver, what is the process and/or measurement used to make it work? Thanks!

Call me tomorrow and we'll talk about it!
If it is a take down, and is hand tight, then it won't matter; it's all clearance.

quote:

Originally posted by dpcd:
I have heard the term crush fit all my life and it is nonsense.
Originally they were fitted and torqued to what seems like whatever the assembler thought enough.

Lee, our other friend Tom explained (back before the internet) the same to me -- that they are designed to hit the torque flange, with the tightness holding the barrel. As this is a less complex union, was fast to setup and produce ..

I didn't read the part that it was a take down. I am going to have to start reading the questions before I answer. But it saves time if I don't.

It's why Tom just says OK to his wife no matter the question, he doesnt listen to her either.

Historically, the inner ring contacts prior to the outer... The .002 is fine and has been suggested in many publications .

Experiments in my part don't seem to bear out some magic correlation number with accuracy

Ona take downs, my goal is to have as much total contact as possioble. I bevel the inner front abuttment,. matching bevel on the barrel and make everything fit up as evenly as possible.

Of more important (in my opinion) is the thread fitment. Originals vary widely on pitch diameter. This is part of the reason you see a variance in torque for original barrels. You will also find due to process a taper on the threads. This also impacts the original torque.

I was taught how to grind my own tool bits about 55years ago. I've always ground mauser threading toolbits to 55 degrees NOT 60. Old school.

Most likely well knopw ..... 55 degree inserts are widely available...