Thread indexing on Luger Barrels Question

[lugercollector]

Does anyone know how the original Luger Barrels were indexed in order for them to be vertical once tightened?....were they completely machined and ready to install?(threads starting always in the same place?)..or were they partially machined,and once tightened, finally machined for the extractor cut and front sight ?...Thanks

[sheepherder]

Originally Posted by lugercollector

Does anyone know...

Do you accept WAGs???

My thought is that there was a fixture that indexed off the front sight base and then the barrel threads were milled rather than turned on a lathe...It's not a lot of stock to mill and could be done in one cut...Requires special gearing for the feed, but I've seen it done on a special screw threading mill for automotive steering gearboxes...

[Vlim]

In post war production, Mauser used a specialized threading machine or 'Gewindeschneidmaschine' as they called it on paper.

It was one of the later steps, after shaping the barrel and sight base. After threading, the ejector slot was cut, followed by milling the feeding ramp and cutting out the dovetail area of the front sight base.

[sheepherder]

Originally Posted by Vlim

In post war production, Mauser used a specialized threading machine or 'Gewindeschneidmaschine' as they called it on paper...

I would guess it used a rotary cutter to mill the threads...I'm looking at two Luger barrels and the cutter marks (and end of cut) are distinctive...

Also a 60º (or whatever angle the Germans used - 55º?) thread cutter, this one is for a vertical mill...I would further guess that the Gewindeschneidmaschine used a horizontal cutter, probably on an arbor, with a much larger diameter & number of teeth...

[Vlim]

Here is a closeup of the threads on an unfinished post war bull barrel.

[sheepherder]

Originally Posted by Vlim

Here is a closeup of the threads on an unfinished post war bull barrel.

That pic does look like a lathe turned thread, cut with a single point cutting tool (although it doesn't show the end of the cut)...but the machinery could have changed from what was done before that...

Just my guess...

[lugercollector]

Thanks Gentlemen!!

[sheepherder]

Gerben - That pic you posted - "Mauser_blanks_1.jpg"...What is that??? Square front sight base...Receiver not machined at the rear...No rear sight...???...

[Vlim]

Rich, it is an in-the-white barrel screwed into an unfinished receiver, both from the 1970s production. The metal part at the rear was retained until the last production steps were completed. It prevented the receiver forks from warping during production, and was finally cut away as one of the last machining steps.

These come from a retired Mauser staff member.

[alvin]

Thanks for the info!

I missed one point -- why was the ejector slot cut after threading, any specific reason? Looks to me those are independent of each other... Or, it's just an arrangement, no specific reason?

[sheepherder]

I know Vlim & Alvin are saying 'ejector slot', but I think they really mean 'extractor cut'...

[Vlim]

Postino wins

[sheepherder]

Originally Posted by Vlim

Postino wins

We have new members following these discussions very closely...I'd hate to have one of them order the wrong part because we mis-identified it...

[sheepherder]

Back in the 80's, I had a 1959 Austin-Healey 100/6 that I decided to put a Datsun 240Z drivetrain in...Worked out pretty good...I further decided to change it over to right-hand steering...All the mounting points were already there; I just had to move the steering gearbox over to the right side of the frame...Not too hard...Everything worked out very well...Until I backed out of the driveway and almost took the corner off my house...

It did not use rack & pinion; it used a steering gearbox with a screw arrangement...When I shifted it to the other side, and flopped all the links, it now counter-steered (car went left if you steered right & vice versa)...

I took the steering box apart and figured out that if I had a new left-hand thread 'screw' cut, I could get it to proper steer...That's when I found a machine shop with the screw-threading machine...The foreman was interested in the job, and offered to do it at a reasonable cost...If I provided the steel stock [4140] and the specially ground mill cutter...The cutter was what I couldn't afford...

I ended up grafting a Triumph TR250 rack & pinion in the front (right-hand drive again), and put the TR250 front brakes & front suspension in as well...

...It's a slow Friday...

[saab-bob]

Postino
Why would you want right hand drive in the USA??? Where you in England at the time?
The 240Z engine would be a good swap,great motor. A buddy put 250k miles on that motor with no major engine work.He sold the car a few year ago,its probably still running!
Bob

[sheepherder]

Originally Posted by saab-bob

Why would you want right hand drive in the USA???

Bob -

Because I could.

I drive a right hand drive truck every day (well, every work day). It is no problem - Took less than 5 minutes to get used to it. Been driving right hand trucks for 28+ years now.

I also put triple SU's on the 240Z motor. I made my own triple carb manifolds. Pic attached is a set just off the TIG machine. The two in the background are a dual setup for a Datsun 521 pickup, same SU's. (The 521/510 4-cyl motor was 2/3 of a 240Z)...

Cut, mill, weld, drill. I used to love this stuff.

[nukem556]

gee, Rich....wanna help me put a Chevy 454 in my MGB?

[sheepherder]

Originally Posted by nukem556

gee, Rich....wanna help me put a Chevy 454 in my MGB?

They still make the 215 B/O/P V-8 down in Oz, IIRC...That'd be the one to swap...I saw a pic of one; they come from the factory [Holden?] with twin SU's mounted on a teepee manifold...

[nukem556]

nah Rich....just a joke..Classic Conversions makes a neat kit using a 92-95 Camaro/Firebird 3.4 v6.....thinking about it....can get 220HP in a MGB....entertaining, i'd think! A lot cheaper and easier than the Rover/Buick 215, and as much or more torque/hp

[sheepherder]

Bob, I had to make all-new heavy-duty [3" x .120" square steel tubing] frames for one Austin-Healey 100/6 and one Triumph TR-6...The original frames were pressed & welded steel sheet, very thin, and rusted out to the point that the doors wouldn't close right...I was lucky in that Robert Bentley sold a manual with every dimension you could ask for and detailed drawings, so I had no trouble cutting & welding a new frame...

...There's no way I would consider putting a V-6 in an old MGB without a stout new frame...