"Ed Huntress" wrote in message ...
On Wed, 13 Jun 2012 15:39:39 -0700, "Bob La Londe"
wrote:

"PrecisionmachinisT" wrote in message
...

"Randy333" wrote in message
news How does one use a gun reamer? the end has no lead in chamfer.

Ebay Item number: 200759361238


That's not a gun reamer.

Its not any form of "gun" reamer I am familiar with.

Probably the EBAY poster was just keyword spamming. Its against the TOS,
but ultimately all EBAY cares about is their own pocket.

Usually a barrel chamber reamer is used in conjunction with a set of Go/NoGo
gages. However, some match guns are adjusted a little tighter than that. I
recall watching Mike Scheerz of Gila River Gunworks chambering on his lathe
to match a gun to specific hand loaded cartridge specifications. Shoulder
fit, head space etc... I wish I had studied what he was doing more and shot
the breeze a little less back then.

There are reams used for preparing a shotgun barrel for internal threading
to use interchangeable choke tubes. The ones I have seen do not look
anything like the one in that picture.

A gun reamer is a type of long reamer, usually made for reaming valve
guides and fluid passageways in aerospace and other applications.
They're were once made like a gun drill, with a single lip, thus the
"gun" designation. The term apparently is also applied to any reamer
with long cutting edges; I don't recall, having not seen the term for
decades.

It's just a long reamer. What everyone (including me) were thinking of
at first is a chambering reamer for rifles. Or, possibly, a shotgun
chamber reamer for reaming out old shotguns made for roll-crimped
shells so they can handle star-crimped types.


For re-chambering rifles, I would think a piloted tool would be the standard design; use of a piloted tool it is without a doubt the process I would specify where consistant and reliable results are required regardless of whether the tool was being used in a lathe, drill press or even being spun by hand.

The tool pictured in the ebay ad however, would probably more accurately be described as simply a flat bottom reamer.....in typical usage, where size and location control are both critical, it is either run in a bushing or else a short portion of the hole pre-bored to a very slightly oversized diameter before the rotating reamer is inserted; the oversized portion is later cut away entirely or is removed by chamfering the hole opening.

Otherwise, the hole can be chamfered beforehand, but your actual results will vary quite a bit depending on whether the reamer is stationary like in a lathe tailstock; or rotating as in a drill press....also, depending on accuracy of centerline alignment, runout, and so forth.....