Reamer bushing selection

[Bidgee]

I'm about to do my first chambering job. Barrel is on order from Lilja (HV taper) and I'm about to order a 6BR removable pilot reamer.

I'd rather not purchase a whole bunch of bushings so is possible to take a best guess at what the bore will be and just order one or two with the reamer or is it a lucky dip? Does the hand lapping result in a large range of finished dimensions?

TIA

Scott

 

[fullersson]

I've always just odered the pilot sets because you can't never tell what brand barrel someone will purchase. If I were just going to do one barrel and didn't want to purchase the pilot set I would call the barrel manufacture and see what they recommend and then I would order 3 bushings. I would order the one they recommend, one size smaller, and one size larger. Brian Brown.

 

[Bidgee]

Thanks Brian

I did contact the manufacturer and he wasnt prepared to nominate a range.

Scott

 

[Rustystud]

If you are not in a hurry you can wait until the barrel is delivered and measure the tennon end. Then order the reamer with the bushing size you need. It is as simple as that. If you do barrels the way Butch Lambert and others do you don't need any bushings.

Nat Lambeth

 

[shortgrass]

I believe all reamer makers bushings interchange, except Clymer. JGS keeps an extensive line of bushings in-stock and on hand. Whenever I've needed one, I've had it in a matter of a few days.

 

[Bidgee]

I believe all reamer makers bushings interchange, except Clymer. JGS keeps an extensive line of bushings in-stock and on hand. Whenever I've needed one, I've had it in a matter of a few days.

Yep, but you live in the US and I'm in Aus.

 

[gzig5]

If you are not in a hurry you can wait until the barrel is delivered and measure the tennon end. Then order the reamer with the bushing size you need. It is as simple as that. If you do barrels the way Butch Lambert and others do you don't need any bushings.

Nat Lambeth

Nat,
Could you or someone else elaborate on this? Does it have something to do with pre-boring the hole at the body angle?
Greg

 

[Rustystud]

Chamfer the bore on the end to be measured. Use pin gauges to measure the bore. You want a bushing that want score the rifling, and want freely spin. If you use a tapered rod to index you want the bushing to be snugg enought that the rod will have two anchor points, one the bushing the other the OD of the tapered rod. Because I do a large number of barrels from tight bore Palma barrels to looser hunting barrels I have about 100 bushings in .0001 " increments from .29699 to .3009.
Nat

 

[jscandale]

I don't nearly as many barrels as Nat, but I have found that ampco bronze makes great bushing material. If I don't have a bushing, I'll just make it. Ampco is a hard bronze but softer than steel. Never have to worry about scoring the barrel and it will machine very nicely with a standard HSS tool bit. Its not a ground finish, but you'll never know the difference after touching it with some fine emory cloth. Just be sure you have mic that measures in tenths. The bushing arbor I think is .189".

JS

 

[gzig5]

If you do barrels the way Butch Lambert and others do you don't need any bushings.

Nat Lambeth

Nat,
Thanks for the reply, but I was hoping to hear how a bushing is not required.

 

[WayneShaw]

By indicating in the bore/groove of the barrel, then drill and bore the hole, this aligns the chamber "hole" with the barrel where the leade will be. The reamer will follow this hole for it's guidance and not rely on the bushing riding in the bore.

A very abbreviated description, but is basically how it's done.

 

[Rustystud]

Maybe Butch will chime in. He made a large post the other day on "Chambering my way". I don't want to misquote him, I beleive he uses a Deltronic Pin and dials his barrel in. Then he drills to closer to the throat area. He then uses a Intrepid long probe indicator to redial in off the lands and grooves to dial in again. Then bores with a boring bar the angle of the case. Then finishes reaming without a bushing allowing the reamer to follow the prebrored hole aligned with the bore. This is the way Speedy teaches his students to do it also.
Nat Lambeth

 

[Rustystud]

I have also made bushings myself but with out a cylindrical grinder it is time consuming and not nearly as accurate as having the bushing precision ground by a shop with an optical compairer.
Nat Lambeth