Soft Jaws

[GregLaROCHE]

What’s the best method for holding a barrel in a three jaw chuck? Copper, leather or something else ?

Thanks

[country gent]

I seldom use a 3 jaw for barrel work, but in the 4jaws I use copper or lead sheet. around1/8" thick I prefer lead unless doing heavy machining. The lead seems to conform to the barrel contours better. On a good chuck with freshly ground smooth jaws you may not need and soft jaws

[GregLaROCHE]

Does it make a difference using a three or four jaw chuck for polishing ?

[kenton]

Wrap the barrel in copper wire.

[Der Gebirgsjager]

I've never found it necessary to do anything other than clamp the barrels in the chuck jaws. If it's marred a little bit from the jaws it's usually not difficult to polish the marks out on a buffer. But, if you don't want any jaw marks you could consider using a split ring like those used in a barrel wrench. Mine are mostly aluminum.

[Chill Wills]

All the above could work and I have copper pennies for heavy work but then for just a light hold like sanding a round barrel I have used a pop can cut up and can even double this for a better hold.
You can cut up three pieces or cut a long strip - diameter times three for a single wrap or diameter times six for a double wrap.
A 3-jaw with a round barrel for sanding/polishing.
A 4-Jaw used with an octagon barrel only makes sense.

[GregLaROCHE]

Good idea using aluminum from pop cans. It’s been a long time since I’ve seen real copper pennies.

[RED BEAR]

A piece of fine sand paper works like a charm

[M-Tecs]

Like most things in live there is rarely a single "best". A better prospective is what is the most preferred?

The goal normally is to have the bore as concentric and parallel to the bore of the spindle as possible.

After that the most preferred is based on what you are trying to do, time verse cost on what your are trying to do, the geometry of the work, what equipment you have, the condition of the equipment and the operators abilities to either take full advantage of the equipment or to overcome it's limitations.

On a barrel blank like a Krieger that the OD is cylindrically ground your methodology may be different than on some of the barrel blanks are basically hot rolled finished that are not true to anything.

Doing AI chambers or threading muzzles on light weight rifle barrels can me a challenge since almost all surfaces are tapered.

What specifically are you doing?

[Chill Wills]

I believe he said polishing in post #3

[samari46]

I get leftover copper flashing from the scrap yard. Wrap the barrel with the flashing and a couple pieces of electricians tape to hold everything in place. Frank