Chambering: indicate bore before threading and/or before reamer?

Chuck

You use a duel changeable pilot to get it close then you swap over to a long stem indicator and align the bore area as well. U don’t have to pull and push the whole barrel with a spider chuck on the rear you can use that just to stabilize the barrel. Same with trueing an action No need for another fixture to hold action u just chuck it up and dial it in with the chuck very fast and no stress on the action twisting
 
OK, not to diss on the TBAS, but the only reason I don't own one is because I can't for the life of me figure out how to secure any of my work in it.
 
alinwa said:
OK, not to diss on the TBAS, but the only reason I don't own one is because I can't for the life of me figure out how to secure any of my work in it.
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I haven't tried it, but Steve Acker once demonstrated putting a bearing surface on a barrel by installing a sleeve attached with bondo that he then trued between centers before using it as a bearing surface for a steady rest (IIRC, it's been a while). He later heated the sleeve with a propane torch to soften and remove the sleeve and bondo. Too much effort? Who knows? Will the bondo expand and impart stress to the barrel? That's a question I'm interested in answering.

GsT
 
It’s unlikely epoxy would put stress in the barrel, especially over a short distance. We use epoxy (chockfast) to bed large diesel engines, for that reason.

This issue I would have with that setup, is getting the bore in the center of all that.
 
alinwa said:
OK, not to diss on the TBAS, but the only reason I don't own one is because I can't for the life of me figure out how to secure any of my work in it.
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You bolt a chuck to it. The TBAS is just an adjustable intermediate between your chuck and headstock.

It allows you to indicate a bore using a 3 or 6 jaw.

You arguably still need the copper wire, because you can still stress the barrel if the OD and ID are not perfectly concentric.

Also, it obviously increases the distance through the headstock.
 
Bnhpr said:
You bolt a chuck to it. The TBAS is just an adjustable intermediate between your chuck and headstock.

It allows you to indicate a bore using a 3 or 6 jaw.

You arguably still need the copper wire, because you can still stress the barrel if the OD and ID are not perfectly concentric.

Also, it obviously increases the distance through the headstock.
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You shouldn’t need anything between the chuck jaws and the barrel shank when working on the chamber end. The TBAS is adjustable for angle and concentricity. I’m nut sure how people are holding the taper when working on the muzzle end, but I suspect they are making tapered bushings to match.
 
Rubicon Prec. said:
You shouldn’t need anything between the chuck jaws and the barrel shank when working on the chamber end. The TBAS is adjustable for angle and concentricity. I’m nut sure how people are holding the taper when working on the muzzle end, but I suspect they are making tapered bushings to match.
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Huhh???

You know this? That the chuck jaws swivel?

And if so..... how do lock the jaws to the taper before you jack the chuck?

I don't think you even grasp the problem....

"tapered bushings" myass.....


As I said, I WOULD ORDER ONE TOMORROW..... if it could hold a barrel properly.

I don't "attempt to reset the centerline on factory actions"..... and I make dies on a collet setup....

BTW I video'd a barrel setup last nite, got a friggin' STRAIGHT barrel.....

sucks

wasted 4 hrs LOL
 
Bnhpr said:
You bolt a chuck to it. The TBAS is just an adjustable intermediate between your chuck and headstock.

It allows you to indicate a bore using a 3 or 6 jaw.

You arguably still need the copper wire, because you can still stress the barrel if the OD and ID are not perfectly concentric.

Also, it obviously increases the distance through the headstock.
Click to expand...


Yeahh.... chuck jaws are somewhat parallel, they're designed to mash down on parallel surfaces.

I don't work with parallel surfaces, with barrels....

I have no idea to what you're referring with the "you arguably still need copper wire"
 
BTW, id and od are almost NEVER concentric..... I videotaped a setup last nite, picked a barrel out of the box and the friggin thing WAS concentric, and straight.... and consequently my video shows nothing useful! Except that Krieger barrels are "perfect" just chuck em up between centers and hack away :) :)
 
alinwa said:
Huhh???

You know this? That the chuck jaws swivel?

And if so..... how do lock the jaws to the taper before you jack the chuck?

I don't think you even grasp the problem....

"tapered bushings" myass.....
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The entire chuck "swivels" and the backing plate is a set-tru style. If you make a split bushing that is parallel on the OD and tapered to match the ID then grab it with a chuck or collet, it will hold. The chamber end is a non-issue because it's parallel, at least on the barrels I typically work with.

I think I grasp the "problem" very well.

Edit: tapered bushings, especially with the taper working away from the cutting force is certainly not as good as grabbing a parallel surface. I found I could push the barrel back if I hogged it with a WNMG 32 like I would bar stock. I now use a VBMT 331 600 sfm, .010 ipr, .015" doc and haven't had an issue since. I can guarantee it is far better than one would get with a spider chuck.
 
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We don't do similar work...... same planet. different worlds.

I'd glue the stinkin' thing into a pipe looong before I'd try "match" tapers for effectual clamping

You wanna' talk about bending barrels! Putting things in tension! This presumption that od's and tapers are useful to index from just doesn't fit my worldview


sorry

And saving the entire shank just to set up on? Using a barrel with a long shank? I can't normally afford all that mass wadded up near the action ring



etc



etc




As I said..... let's just stick with "it doesn't work for me", I don't need convincing.



In the same way that 40yrs of my wife telling me "just try it, it's good" doesn't somehow turn broccoli into food

(I tell her "my food EATS your food".... but she still tries to tell me brussel sprouts are "food")


and I STILL haven't eaten a vench'table since't I left home....
 
alinwa said:
I'd glue the stinkin' thing into a pipe looong before I'd try "match" tapers for effectual clamping

You wanna' talk about bending barrels! Putting things in tension! This presumption that od's and tapers are useful to index from just doesn't fit my worldview
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I'm really confused how you think this would even remotely bend a barrel? And using the TBAS has nothing to do with indexing off the OD of the barrel. I don't think you understand how it works.
 
Rubicon Prec. said:
I'm really confused how you think this would even remotely bend a barrel? And using the TBAS has nothing to do with indexing off the OD of the barrel. I don't think you understand how it works.
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I’m interested in this. I’ve not heard of the tbas before. Great explanations. I appreciate you trying to teach us something new.
 
Rubicon Prec. said:
You shouldn’t need anything between the chuck jaws and the barrel shank when working on the chamber end. The TBAS is adjustable for angle and concentricity. I’m nut sure how people are holding the taper when working on the muzzle end, but I suspect they are making tapered bushings to match.
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Agreed, if the bore is concentric to the outside of the barrel, or uniformly eccentric at muzzle and breech. Unfortunately, thats not what I have seen with most blanks.
 
Bnhpr said:
Agreed, if the bore is concentric to the outside of the barrel, or uniformly eccentric at muzzle and breech. Unfortunately, thats not what I have seen with most blanks.
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No, the TBAS is particularly designed to take out that non-concentricity as well as lineal misalignment. If the bore were concentric to the outside and straight, a regular chuck would do (well, you'd have the gripping problem...).

GsT
 
alinwa said:
We don't do similar work...... same planet. different worlds.

I'd glue the stinkin' thing into a pipe looong before I'd try "match" tapers for effectual clamping

You wanna' talk about bending barrels! Putting things in tension! This presumption that od's and tapers are useful to index from just doesn't fit my worldview
Click to expand...
Do you realize that the TBAS has nothing other than gravity acting on the opposite end of the barrel that you’re working on? It’s not exact, but it’s probably the setup that closest matches the way a barrel will actually hang off the receiver.

alinwa said:
And saving the entire shank just to set up on? Using a barrel with a long shank? I can't normally afford all that mass wadded up near the action ring
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I guess we work on different types of rifles then. Both of which are not matching this page’s title. Buy, FWIW, I’ve built rifles in the 8lb range with scope that are very accurate with a parallel shank long enough to grab with a chuck. That same rifle will probably be used to take critters at very long ranges.

alinwa said:
As I said..... let's just stick with "it doesn't work for me", I don't need convincing.
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I’m thinking that’s because you don’t quite grasp the concept of the TBAS. No harm. But If holding the part is your main issue, I can promise there are ways to hold a barrel far more securely, and far more stress free than between 4 points at each end (regardless if it’s a spider chuck or 4J with a copper wire ring contact).

alinwa said:
In the same way that 40yrs of my wife telling me "just try it, it's good" doesn't somehow turn broccoli into food

(I tell her "my food EATS your food".... but she still tries to tell me brussel sprouts are "food")


and I STILL haven't eaten a vench'table since't I left home....
Click to expand...

How many years were you building rifles before you discovered the “Gordy method”?

Don’t get me wrong, I’m not crapping on any method. Every. Single. Method. Has flaws. We use the method that makes the most sense to us, with the tools we have available. I don’t think there’s a shooter out there that could determine the method used to chamber on target using a blind taste test. If that shooter exists, I’d love to meet him and pick his brain.
 
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