Holding a barrel in a 4 jaw

[Lucky Shooter]

I've used copper wire stubs since I started----I make no claim to be using
the best method. This works----I like it.

Simple test: If your indicators read the same at the finish as they read at the
start------you've done some things right.

Some time just for grins---before removing the barrel, loosen your outboard
spider screws and move the barrel around by hand. I've never seen this require
enough force to bend the barrel.

Just one guy's observation and opinion.

A. Weldy

 

[skeeljc]

I've used copper wire stubs since I started----I make no claim to be using
the best method. This works----I like it.

Simple test: If your indicators read the same at the finish as they read at the
start------you've done some things right.

Some time just for grins---before removing the barrel, loosen your outboard
spider screws and move the barrel around by hand. I've never seen this require
enough force to bend the barrel.

Just one guy's observation and opinion.

A. Weldy

Please describe your "copper wire stubs".

 

[Lucky Shooter]

The "stubs" are short pieces cut from a length of bare copper wire----about
.6" to 3/4".

Not sure abut the wire diameter but think it's #6-----some like #4.

A. Weldy

 

[skeeljc]

The "stubs" are short pieces cut from a length of bare copper wire----about
.6" to 3/4".

Not sure abut the wire diameter but think it's #6-----some like #4.

A. Weldy

I assume you align them 90 degrees to the spindle axis? Do you put them on a jaw tooth or between the teeth? Which tooth/space?

 

[Lucky Shooter]

I put them in the forward groove of every chuck jaw.
As the jaws are tightened during dial-in of the barrel,
the copper stubs are formed into the jaw grooves and
to the shape of the barrel.

Crank down on the chuck wrench during the final steps
of dialing in to prevent slipping and you should be good.

BTW, I don't expect to buy a buck-type chuck and I'm
open to better and more simple methods.

A. Weldy

 

[ACF]

I forget where I saw that- but those are EDM'd into the chuck jaws.
Great idea, just not cheap to do it.

I've got no complaints with the gimbaling V-block setup, everything moves freely as it should.
When I adjust one axis of the outboard spider screws, the breech moves exactly how I expect.

 

[ACF]

I like the idea of the gimbaling v-blocks, but what keeps the barrel from gimbaling when doing the machining such as threading? Is it the spider on the other end of the barrel what keeps the barrel from moving or does just cranking the pieces tight with the bolts doing the job?

Chris

 

[tobnpr]

Is it the spider on the other end of the barrel what keeps the barrel from moving

Yes. Outboard spider is what prevents gimabling when machining (and what allows you to make the needed adjustments/gimbaling prior to machining)

 

[LVLAaron]

Yes. Outboard spider is what prevents gimabling when machining (and what allows you to make the needed adjustments/gimbaling prior to machining)

What size are those aluminum blocks? 3/8th's square?

 

[tobnpr]

^^
Yeah, roughly 3/8"- length was based on clearance to the spindle face from center of spider, made them as long as would work (about 1-1/8").
Ran a 45 degree end mill down a piece of scrap aluminum stock. 1/4" ball endmill to drill out the brass tipped screws to seat 1/4" bb's which were epoxied into place. Drill out center of blocks same way with the ball endmill to seat the bearing. Easy stuff.

Works well, and I'm perfectly satisfied with it. Always willing to try it a different way (it's how I learn); I just got the spacer rings from McMaster to try Bamban's method.