New grizzly "south bend heavy ten"

[Boyd Allen]

Here is a link to a thread with pictures and other information. http://benchrest.com/showthread.php?91876-pics-of-my-first-benchrest-build-in-progress/page2 It is not the same as a steady rest. A steady rest requires that the OD that the steady rest runs on be concentric with the desired CL of the work, in the case of a barrel, the bore. A mid bed half headstock is dialed in like a right side spider on the main headstock. The OD does not have to be concentric with the CL... significant difference. Years ago, Chet Whitebread built the first one that I heard of, for his 9" SB, before he got his heavy 10. He found a headstock, cut it in half and made the rest of the pieces. I thought that it was clever then, and I still do now. Once you have one, if your bed is long enough, a lathe with a long headstock is no longer at any real disadvantage for barrel work. If you bore out the spindle, or scratch build one, you can use a lathe that would normally be limited to barreling with a steady rest, dialing it in like one would through the headstock.

 

[alinwa]

............. A steady rest requires that the OD that the steady rest runs on be concentric with the desired CL of the work, in the case of a barrel, the bore. A mid bed half headstock is dialed in like a right side spider on the main headstock. The OD does not have to be concentric with the CL... significant difference.

Ohhh, well said Boyd

"significant difference" is an understatement!

al

 

[JerrySharrett]

Since it is like a headstock with a spindle riding on bearings, one could use a 4 jaw, set-tru or spider chuck on it and be able to adjust both ends any way they want.

This "thing" can't allow adjusting the barrel the way I want it on the muzzle end when I am chambering. The benchrest barrels I chamber are from 29" blanks. I generally cut about 7" off the muzzle. This leaves some barrels where the OD and ID are way out from being concentric with each other. I correct for this by indicating the BORE of the muzzle so I end up with a barrel that shoots straight ahead and is within 2" POI of the barrel I just removed.

Why am I going around and around on this post when I have no intention of ever making, buying, or using one of these contraptions? Why? Its mid Winter, 8F and ice on the roads so I can't handily get to a shooting bench!!

 

[JerrySharrett]

Looking back at the "my first build..." post that setup looks like an easy way to put the barrel in a strain thus inducing stresses that can and will change as the barrel heats and cools unless it is cryo'ed afterwards.

Interesting thoughts being put into the chambering process though. Press on.

On the other earlier post referenced above, that lathe is a South Bend Heavy 10 so why not just chamber through the headstock?

 

[B.Larson]

Here is a link to a thread with pictures and other information. http://benchrest.com/showthread.php?91876-pics-of-my-first-benchrest-build-in-progress/page2 It is not the same as a steady rest. A steady rest requires that the OD that the steady rest runs on be concentric with the desired CL of the work, in the case of a barrel, the bore. A mid bed half headstock is dialed in like a right side spider on the main headstock. The OD does not have to be concentric with the CL... significant difference. Years ago, Chet Whitebread built the first one that I heard of, for his 9" SB, before he got his heavy 10. He found a headstock, cut it in half and made the rest of the pieces. I thought that it was clever then, and I still do now. Once you have one, if your bed is long enough, a lathe with a long headstock is no longer at any real disadvantage for barrel work. If you bore out the spindle, or scratch build one, you can use a lathe that would normally be limited to barreling with a steady rest, dialing it in like one would through the headstock.

Yes there are a few ways to chamber barrels.And get good concentric chambers.The main thing to remember is to not inflict (bend) tension on the barrel in the set-up.That is the beauty of the steady rest...it does not inflict tension,and the reason why a lot of barrel makers/gun builders choose it.

bill larson

 

[Rubicon Prec.]

This "thing" can't allow adjusting the barrel the way I want it on the muzzle end when I am chambering. The benchrest barrels I chamber are from 29" blanks. I generally cut about 7" off the muzzle. This leaves some barrels where the OD and ID are way out from being concentric with each other. I correct for this by indicating the BORE of the muzzle so I end up with a barrel that shoots straight ahead and is within 2" POI of the barrel I just removed.

Why am I going around and around on this post when I have no intention of ever making, buying, or using one of these contraptions? Why? Its mid Winter, 8F and ice on the roads so I can't handily get to a shooting bench!!

You are correct about that. This will not work for your method.

 

[Rubicon Prec.]

Looking back at the "my first build..." post that setup looks like an easy way to put the barrel in a strain thus inducing stresses that can and will change as the barrel heats and cools unless it is cryo'ed afterwards.

Interesting thoughts being put into the chambering process though. Press on.

On the other earlier post referenced above, that lathe is a South Bend Heavy 10 so why not just chamber through the headstock?

Maybe I am missing something, but what is different about this set-up vs. through the headstock with dual spiders as far as strain is concerned?

 

[JerrySharrett]

Maybe I am missing something, but what is different about this set-up vs. through the headstock with dual spiders as far as strain is concerned?

This mid bed headstock creates one point of rotation that needs to be allowed to swivel. The regular headstock creates another rotation point for the barrel where the barrel must swivel if needed. This double swivel/rotation hold on a barrel would work fine if the lathes headstock and this mid bed rotational axii were in perfect co-axial, co-linear alignment but they will not be. On a mini-lathe, which these are, setting on an average garage floor foundation, or as some set them on anti-vibration pads, constantly move thus creating two rotating stress points.

Since a setup of a barrel through the headstock where both "holds" share a common axis of rotation, i.e. the spindle shaft, the barrel itself is not in stress. In a worst case setup the barrel may be being held in a bend but the barrel is not flexing as it rotates.

 

[Rubicon Prec.]

This mid bed headstock creates one point of rotation that needs to be allowed to swivel. The regular headstock creates another rotation point for the barrel where the barrel must swivel if needed. This double swivel/rotation hold on a barrel would work fine if the lathes headstock and this mid bed rotational axii were in perfect co-axial, co-linear alignment but they will not be. On a mini-lathe, which these are, setting on an average garage floor foundation, or as some set them on anti-vibration pads, constantly move thus creating two rotating stress points.

Since a setup of a barrel through the headstock where both "holds" share a common axis of rotation, i.e. the spindle shaft, the barrel itself is not in stress. In a worst case setup the barrel may be being held in a bend but the barrel is not flexing as it rotates.

Makes sense.

 

[coyotechet]

Using my little contraption to do my barrel work. I first do use a steady rest and set up the barrel between centers to turn a flat at the muzzle end after cutting off 3 to 7 inches. The flat spot and the bore ID. is now fairly close to the same TIR ( .0005/.001) best I can do with steady rest. I then remove the steady rest and install my cats head contraption and 4 jaw chuck. Using the 4 jaw chuck I just chuck up ¼ inch. or less of the muzzle and indicate off the flat and at the cats head I indicate the bore in using the 4 allen brass tipped set screws and only using the little hand held ball wrench to adjust the barrel in (.0001 or darn close) Using the little ball wrench and adjusting with light finger tension until I get the (.0001) I don’t think I can put any stress to the barrel as I can undo anyone of the 4 set screws and the indicator needle will not move. Yep takes me longer but I do get a better TIR and that is what I want before I do any threading or chambering to my barrels. Like I said earlier I now use my Heavy 10 and go thru the head stock using the Grizzly rod system.

Chet
Bench Rest and Lathes

 

[Jay Cutright]

Good idea Chet. I was thinking about the same thing after reading Jerry's post. I was looking at it thinking that if the 3 jaw wasn't close good enough I would turn the muzzle to fit a 5C collet and omit dialing in the muzzle.
So many here are conditioned to the idea of coaxial alignment they wont understand your concept. I'm surprised Jerry didn't see it, he usually argues in favor of machining barrels to shoot straight.
The long winters must be getting hard on the old man. Lol!
I like your contraption. You could use that on about any bed length or spindle bore. Do a variety of barrels and you will wear your ways evenly across the whole bed instead of just wearing out a one inch spot right in front of the chuck.

 

[JerrySharrett]

OK Jay, I'll guess with you, where did I ever not promote having a barrel shoot straight ahead from the action centerline??

 

[Jay Cutright]

You always do Jerry. I have seen post after post on numerous threads every year on these forums and you always advocate machining the barrel straight in line with the action.
In the case of coyote cheats contraption you said it couldn't work for you, but, if you were to shorten the barrel to within 1" of where you wanted the crown and with the muzzle in a live center turn a shoulder on the muzzle that would be true to the muzzle bore you could then hold that muzzle in a chuck or collet and dial in the breach using the spider in that contraption and be as inline with the muzzle as you could get. So long as the bed is straight inline with the headstock.

 

[Butch Lambert]

Lee,
I sent you an email with photos of a "new" used Harrison M300 lathe. Only 2 barrels have been chambered on it. They are a great lathe.