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Joined: Aug 2013
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Sidelock
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Sidelock
Joined: Aug 2013
Posts: 973 Likes: 23 |
What do you folks use to hold a monobloc in the lathe to bore for sleeving?
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Joined: Jul 2012
Posts: 4,508 Likes: 213
Sidelock
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Sidelock
Joined: Jul 2012
Posts: 4,508 Likes: 213 |
B. Graham, The way I learned is to turn the reamers in the headstock, center the barrel being reamed with a solid center in the tailstock and push it onto the reamer with the tailstock, while "dogging" it to prevent turning with a handvise( vise grips will work) clamped to the locking lugs, riding on the carriage. By doing it this way, before cutting the barrels off, you preserve the convergence of the barrels. If the barrels have been cut already( or if you made an actual monobloc), you will need to set it up at the correct angles in a mill with an angle plate and bored with a boring bar. Others may very well do it a different way. Mike
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Sidelock
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Sidelock
Joined: Aug 2013
Posts: 973 Likes: 23 |
Thanks Mike. I think I understand what you're describing. I was aware of a choke tube fixture for doubles that Colonial made. Jack First listed in an old catalog, but they do not have one.
One thought, probably flawed, was to use a reamer large enough to ream the monobloc by hand. Not sure if there are reamers for that use that would large enough. I'm assuming you'd cut enough to erase the rim cuts.
If I can figure out a strategy, and find new tubes, I would be permitted to do this at school.
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Joined: Jul 2012
Posts: 4,508 Likes: 213
Sidelock
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Sidelock
Joined: Jul 2012
Posts: 4,508 Likes: 213 |
Bill, As long as the old barrels are not cut off, you shouldn't need a fixture. You can get reamers from VME, mentioned in the broken bridle screw thread above. They won't be cheap, but will be much better than trying to use a twist drill. As long as a rifle chamber is not involved (a rifle chamber has too much taper for a reamer to work until it is counterbored large enough to get past the extractor cut then drilled straight. The counterbore is necessary to prevent the drill flutes "grabbing").My friend Walter kept the proper size reamers for 16 ga., right on his lathe, so I didn't have to calculate the correct sizes or the difference in diameters between each step. As I recall, I used about 3 different sizes. You do have to ream past the rim recess. The new tubes were made already turned to size and they set the required diameter of the hole. Since the joint is so large, soft solder is plenty strong enough. I think Walther has a website where you can find the usual standard dimensions of new tubes. This would be useful, even if you turn your own blank from Numrich Arms barrels. If the barrels have been cut off, the boring bar in a mill is much less likely to get messed up than trying to ream or drill it without a good guide. On the other hand, there is little doubt that barrel sets have been successfully finished working around a good many mistakes. The maker will know the mistakes but others won't. Good luck. Mike
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Joined: Aug 2013
Posts: 973 Likes: 23
Sidelock
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Sidelock
Joined: Aug 2013
Posts: 973 Likes: 23 |
Thanks Mike. Do you have the website address, or last name for Walter?
The barrels have not been cut off yet. I think in this case, factoring in costs and the equipment, it would simpler to go ahead and cut them, and use the mill/boring bar method.
The barrels in question are a set of damascus tubes from a Charles Osborne 12ga boxlock. I have $80 in the gun, so the risks are low. I would like to learn this process, and get school credit for the experiment.
A source for tubes I can afford are probably the biggest obstacle at this point.
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Joined: Jul 2012
Posts: 4,508 Likes: 213
Sidelock
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Sidelock
Joined: Jul 2012
Posts: 4,508 Likes: 213 |
Bill, Walters last name is Grass. He lived in Muennerstadt in Germany, but the last time I saw him was Jan. 1982. He was planning his retirement then, infact I helped him renovate his retirement home. Considering the length of time since then I'm not sure he is still living. He was a WW2 veteran and would be over 90 years old now. He would not have a website even if living. There are others that do this work though, such as Henneburger.de, or Zimmerman.de, that do have a website. The total cost would be pretty high and there would likely be a long lead time. Mike
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Joined: Jul 2012
Posts: 4,508 Likes: 213
Sidelock
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Sidelock
Joined: Jul 2012
Posts: 4,508 Likes: 213 |
SKB, I think Walther has a US operation and their barrel blanks would be fully prepared, although a little pricy. To find them in their website, you may need to wade into the German parts. Mike
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Joined: Dec 2001
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Sidelock
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Sidelock
Joined: Dec 2001
Posts: 7,000 Likes: 402 |
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Joined: Jul 2012
Posts: 4,508 Likes: 213
Sidelock
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Sidelock
Joined: Jul 2012
Posts: 4,508 Likes: 213 |
SKB, That is who I was talking about, they also have fully contoured blanks. Mike
Last edited by Der Ami; 09/27/19 01:31 PM.
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