Action truing jig

I'm looking to build an action truing jig but my lathe is screwed up and I cant turn threads. Could I turn an old barrel down so that I could thread the barrel into the receiver backwards and center up the chamber on the tail stock?

I don't understand the purpose. Are you just looking to cut the action face and lugs? If so the threads would have to be class 3. Does not sound like a reliable practice to me..

Yes I'm just looking to square the action face

Best I can tell the threads are a little tighter than class 2. I'm not a machinist but dad was and he taught me a little. I'm going to try it and if there isn't much run-out I'll try truing the face on the action as long as I don't have to remove over a few thousandths.

Why not get a quality hone and stand it on end with some oil. Knock of the highs and be done. Cutting the face with no real reference may be worse than leaving it alone.

I don't follow the logic in screwing the barrel in backwards. I wouldn't use an old barrel anyway, the chambers are never concentric with the threads. To do it right, you need to make a mandrel with barrel threads that bottoms out on the lug abutments. Chuck the mandrel in the lathe and screw the receiver onto that. Then recut the receiver face to be true with threads in the receiver.
But....since you can't cut threads, best leave it alone.

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Originally Posted by sharpshooter

I don't follow the logic in screwing the barrel in backwards. I wouldn't use an old barrel anyway, the chambers are never concentric with the threads. To do it right, you need to make a mandrel with barrel threads that bottoms out on the lug abutments. Chuck the mandrel in the lathe and screw the receiver onto that. Then recut the receiver face to be true with threads in the receiver.
But....since you can't cut threads, best leave it alone.

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Point well taken I'll hold off until I get the lathe fixed.

Quote:

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Originally Posted by sharpshooter

I don't follow the logic in screwing the barrel in backwards. I wouldn't use an old barrel anyway, the chambers are never concentric with the threads. To do it right, you need to make a mandrel with barrel threads that bottoms out on the lug abutments. Chuck the mandrel in the lathe and screw the receiver onto that. Then recut the receiver face to be true with threads in the receiver.
But....since you can't cut threads, best leave it alone.

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That is exactly what my retired gunsmith, coffee buddy did for me. Tried up some bar stock, cut threads in the middle, turn the stock down on either side so he can chuck one end and support the other end. Throw some die on it, spin it once and you will see why you are doing it.