Best practices for threading and chambering.

[butchlambert]

I made a Bald Eagle type pusher, then I took it a step further and made what I call coupled pusher. It utilizes a 1/2 ball bearing held in a pocket, one end bearing in it is the the actual reamer holder and the other is shaft held by ER32 collet. I don't have to hold it, it floats in all directions.

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Nez, don't show all of what you do! Leave a little mystery. For those that aren't aware, Bamban, built the uppers for the top civilian shooter, Keith Stephens, and the Texas Team that smashed the old team record at Camp Perry this year.

 

[Shrek]

Those pictures are like porn to me ! Good motivation to get a shop built.

 

[Hal]

Adam

I have to disagree with you about Jackie Schmidt and precision.

When chambering he centers the muzzle end of the barrel and trues it for a sleeve that just fits in the spindle.
Next he reverses the barrel, and centers the chamber end, cuts the thread O.D.
The chamber is drilled just under full depth, than a boring bar, (matching the angle of the case),is used to bore the hole dead true to the center of the lathe.
He cuts the last .020 -.030 of the chamber by hand.
The threads are cut last. Check your work.

When he talks about chambering and threading barrels and how different people set up in their lathe. He says they need to know not only how to, but also why they do what they do. And after all is said and done, check your work, the throat, neck, just below the shoulder and the rear of the chamber and threads.
He says his are .0001 - .0002 run out, not bad for a archaic set up.
Jackie has a write up with pictures on the Benchrest forum.

Hal

 

[ab_bentley]

Adam

I have to disagree with you about Jackie Schmidt and precision.

When chambering he centers the muzzle end of the barrel and trues it for a sleeve that just fits in the spindle.
Next he reverses the barrel, and centers the chamber end, cuts the thread O.D.
The chamber is drilled just under full depth, than a boring bar, (matching the angle of the case),is used to bore the hole dead true to the center of the lathe.
He cuts the last .020 -.030 of the chamber by hand.
The threads are cut last. Check your work.

When he talks about chambering and threading barrels and how different people set up in their lathe. He says they need to know not only how to, but also why they do what they do. And after all is said and done, check your work, the throat, neck, just below the shoulder and the rear of the chamber and threads.
He says his are .0001 - .0002 run out, not bad for a archaic set up.
Jackie has a write up with pictures on the Benchrest forum.

Hal

While I won't disagree, the picture doesn't lie. That much tenon hanging out of the chuck is asking for taper in the threads and tenon cuts.

Again, he's familiar with his ways and I with mine. I wasn't implying that his methods were unsound, just that they are very un-orthodox. When you compare that style of chambering to the current trend, it screams archaic. Again, skinning cats has many roads.

Adam

 

[butchlambert]

While I won't disagree, the picture doesn't lie. That much tenon hanging out of the chuck is asking for taper in the threads and tenon cuts.

Again, he's familiar with his ways and I with mine. I wasn't implying that his methods were unsound, just that they are very un-orthodox. When you compare that style of chambering to the current trend, it screams archaic. Again, skinning cats has many roads.

Adam

You might want to stand over Jackie's shoulder sometime. This is a link to Jackie's 30BR.

http://bulletin.accurateshooter.com...-agg-at-100-yards-with-30-br-best-in-history/

I think archaic is pretty good don't you think?

 

[boltman223]

While I won't disagree, the picture doesn't lie. That much tenon hanging out of the chuck is asking for taper in the threads and tenon cuts.

Again, he's familiar with his ways

Adam

I don't want to argue, but I feel it is worth saying. You may be "asking" for it, but if you do it right you won't get what you "ask" for.

And like you said he's familiar with his ways. And I'm sure he's found ways around any issue that has come about.

 

[butchlambert]

Adam, I personally like my throat area to be under my cathead pivot screws, but I don't understand why he could have taper.

 

[ab_bentley]

Adam, I personally like my throat area to be under my cathead pivot screws, but I don't understand why he could have taper.

Lack of rigidity due to work piece sticking out of the chuck to far.

Again, I'm not saying is wrong, in fact I'm saying it's right, for him. Would you drop your current methods to use his? I wouldn't. Would you chamber in something less than the 10EE?

That's my whole point, use the methods you're comfortable with and have confidence in.

Still we like to do things as well as they can be done. When you find an imperfection in your method, you can ignore it or find a better way. Will it show on the target? I dont know.

This is exactly what I'm saying. Until i find a reason to use another method I'll continue using mine, you yours, and Jackie his. All if done correctly will produce good shooting rifles.

Adam

 

[boltman223]

Adam, I personally like my throat area to be under my cathead pivot screws, but I don't understand why he could have taper.

Butch, I've seen a taper cut on small diameter stuff because of deflection, well and larger stuff to, but it's easily taken care of.

Maybe Adams lathe just cuts a bad taper.

 

[butchlambert]

I do not chamber in my 10EE, I use my 6913 Clausing. It would be a piss poor lathe that couldn't cut a tenon without taper even though it is hanging out more than I do. He doesn't cut his tenon in one pass.

 

[ab_bentley]

but the shit show that will ensue from your question isn't what you're looking for either.

Adam

Almost like the future had been predicted in the second post.

Like I said, I'm not saying it's going to happen, I'm saying it can happen with that set up more likely than a tenon kept close to headstock. That method isn't for me, and doesn't fit the "accuracy" standard but it still sets records , that's all I'm saying. That's whole point of this thread, to discuss chambering techniques, not that I think certain practices are not what I would use. So debase the thread to a squabble and leave the op wanting. Instead of complaining about what my opinion is, put your methods up.

I swear having a civil debate on this forum is like herding cats sometimes

 

[butchlambert]

Almost like the future had been predicted in the second post.

Come on Adam, you are better than that.

 

[Hal]

Adam

If you get a chance check out Jackie's chambering post over on the benchrest forum.

Hal

 

[ab_bentley]

Come on Adam, you are better than that.

You're right, I am. I should have known better than to try and explain my opinion and why I wouldn't use it.

Adam

 

[Hal]

The wire Adam is using to make a pivot is #6 SD (soft drawn) copper wire, used between a meter loop and a ground rod.

Hal

 

[butchlambert]

You're right, I am. I should have known better than to try and explain my opinion and why I wouldn't use it.

Adam

Adam, I don't disagree with your setup. I just can't fault Jackie with the success and many many years experience in the machine shop.

 

[Shrek]

I think we should all be able to talk about pro and cons, issues we have found with certain methods without directly putting down some one else or their ways. These kind of threads could be valuable if they dont end in shit slinging.

I agree 100% . If we all agree all the time there would be no progress or much learning. Criticism and the discussion that come from it are often the most enlightening. You don't have to be wrong for someone you disagree with to be right. There's plenty of ways to get the job done.

 

[Hal]

Alex

Like you I enjoy the exchange of ideas and picture are a big plus. It has help me a great deal and gives me something to think about.

Alex just a question on the first picture you posted. What were you doing that the with the barrel chucked so deep if you don't mid me asking?



Hal

 

[Tim Singleton]

I don't know that it ever happened to me. But I got worried about the soft copper wire. Probably me over tightening the jaws. I made a split ring from a piece of aluminum. It has a heavy chamfer on each side about .375 wide taper on both sides to give .250 contact surface on the barrel so it can pivot. Just another way to skin it

 

[Hal]

Alex
If you get a chance take another picture of your reamer holder.

Thanks
Hal