Guerrilla Gunsmithing # 3 - 7.65 Luger Colt Gov't Model Barrel

[Neil Young]

Postino:
Please tell me how you lined up the barrel to be perfectly true with the reamer and the end mill--in the horizontal and vertical direction as well as eliminating any angular misalignment. I know that you can move your compound from side to side, but how do you measure. Also, I don't see any vertical adjustment on your vise.

I've wanted to do a similar operation in the past, but the setup was "beyond the scope of my text". I once had an engineering professor that when stumped by a question would always say--"That's beyond the scope of this text.". Hopefully you can tell me how to do it. Thanks.

Neil

[sheepherder]

Got the liner roughed out tonight...Gotta break now...

[sheepherder]

Originally Posted by Neil Young

Please tell me how you lined up the barrel to be perfectly true with the reamer and the end mill

It's Gonzo Gunsmithing at its finest!

First, the fixture I used is for vertical boring & threading of the P-38 breechblock (for installing long barrels); I'll make another one for this horizontal reaming, but for this 'feasibility study', it'll do...

I use a set [2] of drill blanks from Travers.com in 8.75mm/8.8mm/"S" [8.85mm]/8.90mm sizes...I put the size that is a snug fit in the barrel in the lathe chuck and another in the tailstock chuck. Run the lathe and make sure drill blank has no runout. Mate the two drill blanks end-to-end in their respective chucks. Center the tailstock if necessary.

I clamp the breechblock in the fixture and hang the assembly {breech first] on the drill blank in the lathe chuck. Position the table under the breechblock with the vise just loose on the table. Push the vise fixed jaw up against the fixture. Tighten the vise jaws & clamp the fixture. Run the tailstock drill blank into the barrel - it should go right in without hitting an edge. If it does hit, untighten the vise jaws and reposition the vise. If it goes right in, clamp the vise to the table. Lock the table crossfeed.

Now run the tailstock out of the way and run the table out, then back in. The lathe drill blank should go in smoothly without hitting an edge (the drill blanks have square edges).

Take drill blank out of chuck, put reamer in (or end mill).

That's it. I do not use the power feed; I use the longitudinal micrometer feed on the end of the lathe bed. I ream only 1/32" to 1/16" at a time, back off & blow chips out, cutting oil on reamer each time. Lowest speed lathe has (400rpm).

Came out pretty good for such a barnjob, huh???