revolver cylinder line boring

[tuner]

I have read about line boring cylinders, understand the concept and can definately see how that would enhance accuracy of a revolver. I read with great interest Mr. Lee Martins excellent article on his conversion of an OM .357 to a .44 Sp., the fabrication of a cylinder, etc.; great article, great "Smighing"! The way he marked and dialed in his chambers was most interesting, appeared to be done very precisely and the accuracy results verified his percision. He, however, did not line bore the cylinder, certainly no criticism, and that is the procedure I am curious about.

When line boring is a bushing screwed into the frame in place of the barrel through which a drill is used to start the boring process and then a single point cutter is inserted and used to clean up the bores whcih are then chambered with a reamer? How is the cylinder locked in place to prevent movement during the boring process. I would imagine some sort of clamp goes around the frame and locks to the cylinder in place.

Does anyone have photos of the tools and the setup they can post or can give a description of the process.

Appreciate any input.

If this is a second post of this question I apologize as it did not look like the original post went through.

 

[cellar701]

Jerry Kuhnhausen's book (on Single Action Rugers) has an illustration on page 221 which shows the bushed method. Also, Manson Reamers catalog has some pictures of the bushing and reamer. It's something I'd leave to the professionals, personally.

 

[Ale-8(1)]

I'm having a hard time understanding how cutters and reamers can be passed thru a cylinder that's actually in the gun. Can ayone shed some light on this procedure? It has aroused my curiosity, as well.

Lee "center-punches" his cylinder blanks with a device screwed into the frame in place of the barrel, then removes the cylinder and drills/reams the chambers from the "center-punch" locations. This allows drills and reamers to pass thru the chamber bores.

 

[cellar701]

Line boring via the bushing method involves removal of the barrel and fitting a hardened, threaded bushing in place of the barrel. Use tight fitting base pin, shim cylinder forward and use fixtures to ensure proper alignment against cylinder latch, etc. Bore thru bushing into cylinder; repeat for all 5 or six holes. Then chamber ream the cylinder ; ream the throats. I haven't done it - description based on my reading of the techniques.

 

[Ale-8(1)]

Understand the concept, but I still can't see how the boring tool and reamer can complete the bore thru the cylinder with the cylinder still in the gun. And the chamber has to be finish-reamed from the REAR END.

The threaded bushing thing is exactly how Lee "punch-marks" his cylinder blank while locked into position by the pawl and bolt.

Anybody got a pic of the "line boring " operation?

 

[cellar701]

Yes, the cylinder is removed for the chamber and throat reaming operations. Only Pics / figures I've seen are in Kuhnhausen's book(s) as referenced above.

 

[flatgate]

Yes, just the "empty" receiver/cylinder frame is jigged up so a line bore reamer, which is basically the same diameter as the desired throats, is run from front to back in each "piloted hole" bore in the cylinder. One prefits the cylinder latch so it "firmly" locks the cylinder in place for all 5 or 6 or ? chambers. The depth of the line bore varies with calibre, preferences, et. al.

The line bored cylinder is then "fixtured" so it can be "rough drilled", chambered and finished. Any number of ways can be utilized to perform these operations, depending on the "machine tool" selection available :roll:

flatgate

 

[2 dogs]

What you all are missing is that the cylinder itself is locked in place by a fixture that locks the bolt into the cylinder notch.

 

[tuner]

Obviously this is a question that others were interested to know. I did not expect to get this many responses so quickly. Thanks to all who replied.

Cellar, it is not my intention to try and line bore a cylinder it was just something I was just wanted to understand and know how it was done.

Now, that being said, if someone gave me a junk revolver, which they have not, and I could fabricate all the items needed to do the job with my lathe and mill setup I would give it a try just for the fun of it. But, that will definately not happen to my present battery of revolvers or anything I wasn't prepared to throw away.

 

[cellar701]

Somewhere I've seen some photos on the line boring and fixtures used outside the copyrighted materials in the books but I cannot seem to find it. I toyed with the idea of trying it - but after some more research and checking some pricing on tooling and components it didn't make sense for my projects, especially a one or two-off type of deal.

I have an acquaintance who likes Smith and Wesson revolvers and especially likes .44 Special. He has undertaken some projects to have revolvers re-chambered and some line-bored by a local smith who is very competent and does very good work. The completed work is very nice, but I can't discern any difference in accuracy or tightness/lock-up versus the standard factory fare (which, of course, is very good). That contrasts with the Freedom Arms and some of the excellent Ruger specialty shops (Clements, et al) which are in a totally different class, in my opinion.

 

[cas6969]

Understand the concept, but I still can't see how the boring tool and reamer can complete the bore thru the cylinder with the cylinder still in the gun. And the chamber has to be finish-reamed from the REAR END.

Just a pilot hole is made from the front.

 

[Ale-8(1)]

That would be my interpretation.

In order for the cylinder to be "aligned" with its matching frame, the chamber bores must be located while the cylinder is locked in position in the frame by the pawl and bolt. The cylinder is then removed and the rest of the bore/chamber operations performed from the pilots.