Luger Steel Lanyard 'Staple'

[Eugen]

As a side bar, can someone please enlighten me regarding the differences between the terms "press fit" and "staked"? Thank you.

To me "staking" is what I needed to do as a boy scout when pitching a tent. As for "press fit", that is how my stomach feels in my jeans after an evening grazing at the local $10.95 all you can eat buffet.

[Olle]

Originally Posted by Eugen

As a side bar, can someone please enlighten me regarding the differences between the terms "press fit" and "staked"? Thank you.

To me "staking" is what I needed to do as a boy scout when pitching a tent. As for "press fit", that is how my stomach feels in my jeans after an evening grazing at the local $10.95 all you can eat buffet.

When you "stake" a lanyard loop, you push it through he holes so the ends protrude slightly on the inside of the frame, then you use a punch and a hammer to deform the ends so the loop can't come out again. "Swaging" is a similar method, but you use a formed tool that's pressed against the end to mushroom it in a controlled manner.

Press fit (or "interference fit") is what the name implies: You press it in and the part is held in place by friction. This requires a more precise fit (IIRC the total tolerance needs to be within 1/1000") so you would normally have to ream the holes to an exact dimension instead of just drilling them. In the case of the loop you'll also need a press tool that fits snugly on the loop, or else it will be deformed when you press it in.

[sheepherder]

Originally Posted by Olle

Press fit (or "interference fit") is what the name implies: You press it in and the part is held in place by friction.

You can have an interference fit without pressing - Heat the hole and chill the pin. Let air cool. Half a thousandth o/s pin is adequate for this.

Swaging is best done with a rotating concave tool to heat up the pin end by friction while pressing down with your arbor or press. This makes a nice rounded dome that overlaps the sides of the hole.

My vote for the Luger loop is peened in place. A special holding fixture for the frame, stick the loop in the frame and place it in the fixture, lower a ram to touch the ends of the loop (inside the frame) then whack the ram with a BMFH...

Simple enough for slave labor and not time or machine intensive.

I use this method for re-assembling Buck 110 and 112 folding knives after I swap blades in them...

[Olle]

Originally Posted by sheepherder

You can have an interference fit without pressing - Heat the hole and chill the pin. Let air cool. Half a thousandth o/s pin is adequate for this.

Swaging is best done with a rotating concave tool to heat up the pin end by friction while pressing down with your arbor or press. This makes a nice rounded dome that overlaps the sides of the hole.

My vote for the Luger loop is peened in place. A special holding fixture for the frame, stick the loop in the frame and place it in the fixture, lower a ram to touch the ends of the loop (inside the frame) then whack the ram with a BMFH...

Simple enough for slave labor and not time or machine intensive.

I use this method for re-assembling Buck 110 and 112 folding knives after I swap blades in them...

Yep, a rotating swaging tool would probably be the best way to do it. From what I gather, you can even get some friction welding effects by doing that, and that would make it stick like the dickens. Like they say around here: "that ain't going nowhere!"

And just to argue with you: I just looked at some of the pictures, and looking at how smooth the frame is inside I would guess they are swaged. Staking will often leave marks deep enough to remain after you grind it flush, especially if you use the specialized gun manufacturing tool you recommend. Even a highly skilled BMFH operator would have this problem, so I'm voting for swaged.

I know that many wartime guns were simplified to cut production time and allow for unskilled labor (which, unfortunately, is the way most guns are made nowadays as well...), but I don't know if any changes like that were ever made to the Lugers. I can't recall ever seeing a "last ditch" variation, but they may be out there?

[sheepherder]

Ed had said that he wanted to press/punch the loop out of his junk Luger gripframe. I would be interested in seeing the inside of the frame where the loop holes come through. Just to see if the holes were chamfered. That would eliminate the need to swage the ends. They could even be slightly loose in the hole and still not come out, if they were peened or even just hammer-pressed in place and then the ends ground or milled.

Someone (might have been Ed again) said that they had observed loose lanyard loops. That they hadn't fallen out leads to belief that the inner ends were bigger than the holes.

We need pics.