True Bore Alignment System

[Addley]

Alex

There's 3 problems with flexing a barrel to get it dialed. One is that some cartridges are long enough that the flex is in the chamber. Another is if you index barrels the flex will fool you as to where to point the barrel. But the most important one is that when your flexing the barrel its fighting the setup and when you start putting cutting pressure on it its far more likely to more during the process. The barrels should not be moving. So if you’re checking your work and finding you need to dial out a tenth or two after threading for example you have a problem. Most likely flex in the barrel is the issue as well as sacrificial metals like a copper ring in a 4 jaw. Thats a recipe for movement. Now I know someone will ask how much all this matters. I dont know and dont care. Im charging the customer to do the job to the best of my abilities, so thats what I try to do. For the hobby guy, this probably is not an area to fuss over too much.

Alex. What is the best way to chuck and line up a barrel for chambering?

 

[DSMWerks]

I keep getting Proof Research Carbon fibre barrels to chamber and I make sleeves to protect the barrel from the spyders. I started reading through this thread because the jaws will work good only holding on to the steel section of the carbon barrels. This system seems awesome all around but there is some who dont like the idea of added weight and length. I see someone used a 16C collet chuck. So why not an ER50 collet chuck? You can get one that is 4" dia and 2.5" tall and on Ebay for $50. ER50 collets that are 1.2-1.25 range have 2.5" length of engagement. Much shorter and way lighter than a 6 jaw chuck. I'll go get my flame retardant suit on now

 

[WSnyder]

So why not an ER50 collet chuck?

And you are adjusting it how? As in what’s your plan for how you will accomplish dialing in a barrel in with it???

 

[DSMWerks]

Well if you attach this collet chuck to the TBAS in the same way you bolt a 6" six jaw chuck it will be 25-30 lbs lighter and 3 inches shorter and use the TBAS just like normal. If you can chamber a barrel putting three bolt holes in it shouldn't be to hard.

 

[DSMWerks]

I just checked my Bison 6" adjust tru and the jaws are 1.30" tall that contact the barrel. An ER50 collet contacts 2.5" long so I like that idea better too. Most barrels only have so much straight diameter but the more the better right?

 

[WSnyder]

Well if you attach this collet chuck to the TBAS in the same way you bolt a 6" six jaw chuck it will be 25-30 lbs lighter and 3 inches shorter and use the TBAS just like normal. If you can chamber a barrel putting three bolt holes in it shouldn't be to hard.

Gotcha. Wasn't clear (to me) that you were putting it on a TBAS.

 

[DSMWerks]

The ER50 collet chuck is a substantial piece. Heavy duty but half the length of the 6" three jaw. I will have to fit it to a TBAS and give it a go!

 

[LVLAaron]

How will you dial it in?

 

[boltfluter]

How will you dial it in?

I would assume the same way as with the chuck on a TBAS. I am assuming that he is using a TBAS. Or, I am totally wrong and in the weeds somewhere! Lol
Paul

 

[WayneShaw]

The ER50 collet chuck is a substantial piece. Heavy duty but half the length of the 6" three jaw. I will have to fit it to a TBAS and give it a go!

If you took those soft jaws off and clamped a barrel on a copper wire, your depth would be the same per your photo.

 

[LVLAaron]

I would assume the same way as with the chuck on a TBAS. I am assuming that he is using a TBAS. Or, I am totally wrong and in the weeds somewhere! Lol
Paul

The 3/6 jaw is a set/adjust true, so you can move it around. the collet chuck just bolts on and doesn't have the jack screws to move it around.

 

[LVLAaron]

If you took those soft jaws off and clamped a barrel on a copper wire, your depth would be the same per your photo.

That would negate the purpose / use case of the TBAS.

 

[tac284]

All radial and axial adjustments are done in the body of the TBAS, the adjust/set-tru in the chuck is of no value when used with the TBAS.

 

[Alex Wheeler]

No matter how you choose to dial you need to radially dial in 2 points. Axial will align the bore with the ways not the spindle.

 

[LVLAaron]

All radial and axial adjustments are done in the body of the TBAS, the adjust/set-tru in the chuck is of no value when used with the TBAS.

AH! My fault. I thought it relied on the chuck. Thanks for the clarification! In that case, I really like the ER collet idea.

 

[DSMWerks]

No that chuck pic was just for reference. I did not have the TBAS on for the pic. Yes if I took the jaws off and used the copper wire method it would be sticking out about the same. But I preferer to hold the barrel at one end only in a relaxed state. And the complaint some people mentioned what how much longer the TBAS was. This was intended to be an option to those, like me who like who want it shorter. About 20 lbs lighter too!

 

[DSMWerks]

And the ER50 collets have more length engagement and come in any size you need that fit the barrels radius better than jaws.

 

[LVLAaron]

And a heck of a lot cheaper than any compatible 6 jaw.

 

[BuffaloBill]

I like your idea of mounting an ER50 collet chuck to a TBAS. Looking at a dimensional print for the 16C chuck listed as an option on the TBAS site, it looks like the TBAS’s chuck mounting holes are on a 140mm bolt circle. Have you found an ER50 chuck having that mounting bolt circle? Or would you just drill & tap your own mounting holes in the TBAS?

Do you have a link for the $50 one?

Thanks.

 

[BuffaloBill]

I did a bit of looking online, and see there’s an ER50-D160 on eBay and other places. It appears to have M8 threaded holes on a 142mm triangular bolt circle. Perhaps one could open them up to 10mm through holes, correcting them to the 140mm bolt circle. The OD is 160mm or 6.299”. I see 6 1/4” chucks are sold to mount to the TBAS. Maybe the 160 OD will need some trimming(?).

Those having this 160mm mounting flange are priced higher than the 100mm, etc. I don’t yet have a TBAS to see if the radial plate can be drilled & tapped for smaller bolt circles. My wife did just say “yes, she needs a TBAS for her lathe”, so I wasted no time in placing one on order!

Do any of you with a TBAS know if the radial plate has keep-out areas behind the mounting surface?

Edit to add: Here’s a link to an inexpensive one. https://www.amazon.com/ASZLBYM-ER25...r-ER50-D100/dp/B0DQ859MD9?tag=accuratescom-20