True Bore Alignment System Review

[jscandale]

Well, I drilled some half inch holes in the TBAS, but it didn't really do much, however I did run it at 1250 rpm and it has much less propensity of chatter at the higher rpm scale. It didn't help, but didn't hurt either. I'll wait to hear from Jeff.

JS

 

[jeff walker]

We are mainly talking about getting chatter while parting off. You're not trying to part off at high speeds are you ?

 

[Jay Christopherson]

We are mainly talking about getting chatter while parting off. You're not trying to part off at high speeds are you ?

I've tried everything from 70rpm on up to 755rpm, at various advance rates using carbide or HSS. 460rpm with .0056" advance with carbide cuts like butter in my 3-jaw (on barrel steel anyhow). HSS at 115 with a slow advance seems to be the least chattery in the TBAS for me, but least still == a lot.

 

[jeff walker]

Ok. Just making sure we are "on the same page"

Typically I part off at 215rpm and a.0024" feed rate on both the 16" lathe with TBAS and the 14" lathe with the 4-jaw.

 

[jscandale]

We are mainly talking about getting chatter while parting off. You're not trying to part off at high speeds are you ?

Gosh, no. I do all of my parting in the other lathe with coolant at about 325 rpm with a HSS blade. The only time I use a parting tool in conjunction with the TBAS is making a shallow relief cut for an AR barrel extension, but when I do, it's a slow advance at @ 920 rpm in order to remove about .050".

JS

 

[woodbutcher]

I have been using a TBAS for several months with no issues. I have it mounted on a Grizzly 16x40 gunsmithing lathe with a D1-6 mount. I have not parted off anything yet; I cut all my barrels with a horizontal bandsaw. I chamber using the Gordy Gritters method and it has greatly reduced the time required to indicate a barrel in. It requires a little extra time to make bushings to grip a tapered barrel to do crowning operation. I would like to hear from anyone if they have developed a better method to perform this operation. I would recommend this chuck to anyone chambering barrels this way.

 

[Jay Christopherson]

It requires a little extra time to make bushings to grip a tapered barrel to do crowning operation. I would like to hear from anyone if they have developed a better method to perform this operation.

That is the same way I deal with tapered barrels in the TBAS.

 

[jeff walker]

OK, I received the backplate from Nate and I have done some testing. I parted off at various speeds and feed rates and I see no problem with the TBAS on my 14x40 lathe with the D1-4 backplate. I can do faster and more aggressive parting off in my 16x40 lathe, but parting off in the small lathe with the TBAS had no more limitations than the 4-jaw.

I experimented with the tightness of the angular adjustment and the rotational adjustment bolts and found that if you had them a little loose, chatter would definitely be there. I have no idea as to how tight you guys are getting yours, but, I'm assuming you may be treating the bolts like you would spider bolts and a 4-jaw ? Meaning tightening somewhat lightly to reduce the risk of imparting stress on your work piece. Go ahead and tighten them up tight, you cannot induce stress in the work piece by doing so.

I also did some very aggressive turning and had no problems.

----------------Jeff

 

[jeff walker]

Also, I did parting operations with various lengths of barrel out of the jaws. Anything from 1" out to 4" out. Same results. No problems.

 

[jscandale]

Jeff,

Thanks a lot! That was really good information. Thanks for taking the time to perform this test and thank you to Nate as well for sendiing the back plate. I have been getting better results lately, but I have not been able to part off a work piece yet.
I wonder what the difference with your setup is that you are able to perform tasks that I can't. I have to find this our, or I know I'm gonna lose some sleep over it.

Thanks again,
JS

 

[jeff walker]

You're welcome sir.

From what I see, the only thing I can figure is tightness of the adjustment bolts...but of course I cannot do anything other than guess.

 

[Jay Christopherson]

You're welcome sir.

From what I see, the only thing I can figure is tightness of the adjustment bolts...but of course I cannot do anything other than guess.

Jeff, thanks a lot for testing this.

 

[jeff walker]

You're welcome. I hope this in some way helps you guys.

-----------Jeff