A 1800 Meter Luger !

[sheepherder]

Originally Posted by DonVoigt

I'd like to know a couple "details":
-what angle to the bore do you cut the feed ramp?
-also the angle of the extractor cuts.

The extractor cut is as specified in the blueprints; 53º.

Gerry has a post in a related thread outlining the feed ramp angle.

http://forum.lugerforum.com/showthread.php?t=37697

[Rick W.]

I was curious of the angles on the feedramp and the extractor cut too. So I thought either John S's nicely done schematics or the appendix to the book, The Dutch Luger. I don't have John's redo's yet, but have the Dutch Luger book.

The appendix shows the two cuts, the extractor is 51 degrees I believe; appears that the other reference would suggest 53 degrees. I have not noticed that before, so learned something again.

The appendix dwg shows the feed ramp without an angle reference, although the angles visually look similar to me(says the guy with bad eyes). The area is referenced heavily to surfaces and bore line with Cartesian dimensions, so with a little trig, one could get there. For years, I did the crude garage version on such with Cartesian measurements and connect the dots carefully.

Obviously 2 degrees is not much to talk about in most cases. We all grow up in the awe of German craftsmanship here in the states, so we assume(that funny word again) that parts are made to a set of theoretical master documents. Well...........not quite everyone.......but have to reflect on the job done back then by those guys.

I think both cuts take a little discretion as too deep towards the muzzle will cause gap space to occur, and the case only has so much insurance at the web. Especially for the guys that shoot +++++++++++P ammo in their Lugers(not me.... .

Thanks for the pictorial, always interesting to see technique. The front ramp was a new thing to me, appreciate especially seeing that.

[sheepherder]

Originally Posted by Rick W.

The appendix shows the two cuts, the extractor is 51 degrees I believe...

Here's the print from TBLAP; red line points to extractor notch angle, yellow triangle is the ramp. 1.8mm on one side; 2.77mm on the other. It's a right triangle and the hypotenuse is not relevant - using trig table you can work out what the print says the angle is.

But in terms of case blowout, since the extractor cut is given as 53º, you really can't go too far wrong using that, if you don't like the trig answer.

[Rick W.]

I thought the difference in angles, however slight, was an oddity in these dwgs, just surprised me a little.

Angle is angle................but advancement of said angle up the bore is always blowout sensitive.

[DonVoigt]

Originally Posted by sheepherder

Here's the print from TBLAP; red line points to extractor notch angle, yellow triangle is the ramp. 1.8mm on one side; 2.77mm on the other. It's a right triangle and the hypotenuse is not relevant - using trig table you can work out what the print says the angle is.

But in terms of case blowout, since the extractor cut is given as 53º, you really can't go too far wrong using that, if you don't like the trig answer.

Rick,
I know what the drawing says, I just wondered what angle you actually used!

GT and I argue over the best ramp angle, he likes a steeper angle, I like a flatter angle. But not more than about 5 degrees different.

Just wondering what you actually set up to cut.

[sheepherder]

Originally Posted by DonVoigt

GT and I argue over the best ramp angle, he likes a steeper angle, I like a flatter angle.

GT and I had that same discussion some time back. I tend to err on the side of the blueprint. I only differ by 1º from the print.

But you can't fault success. If GT has had no complaints then that must work. More than one way to skin a cat.

[Rick W.]

I reckon another simplistic approach could be just to measure a few vintage takeoff barrels on the lathe. Looks like could do that within reason. Sometimes information can be right before us within reason.

Put the perceived vintage barrel of the day in the chuck and zero out to the chamber perimeter. Most of us have the 0.0001" test indicators and adjust true chucks to support that. Then twist the compound until the indicator reads zero again with the stylus on said ramp. My mind is interested, but my body right now.......is not; so just throwing out a concept.

Not a lot of run on the ramp or extractor cut, but oughta give some idea of the original thoughts. Probably just one of those curiosities, what is a degree between friends?, I doubt if I could cut two of them alike on the same setup anymore........

To some, steeper angle means less exposure. I suspect if G.T. does some of that, it was with some research and soul searching about being proper and the bottom line..........safe. Maybe he even(heavy conjecture inserted) that he now has the compound rotary cutter we visited about long ago to do the ejector slot in one swoop.............