Guide to Re-Strawing your parts?

[Ron Wood]

Originally Posted by Terry Tiell

The reason I decided to use the sand was to heat the parts evenly as the sand helps to hold the heat in.

Very smart! That's the way some of the "pros" do it.

[Terry Tiell]

Its a shame you can't just do the whole gun like this!

[Terry Tiell]

I learned it from doing very detailed welding on thin little dash board parts on old Jags.

[Ben Evans]

Many thanks for this thread, just done a take down lever for my 1917 Arty luger, results are fantastic

[Raulus]

https://www.youtube.com/watch?v=hw4Rl0uG7ok
an interesting video about heat treatment. at about minute 20 it explains and shows the strawing procces

[superc]

The procedures for heat treating each part and from year to year differed. The steels did change. So did the desired color and tint.

The complete instructions can be found here. I don't know why someone stuck them on Scribed, but you can read them all there fot free without having to get a $9 a month membership. All temperatures are in Centigrade.

http://www.scribd.com/document/15362...structions-pdf

[DonVoigt]

There is a sticky here on strawing too- or maybe the other luger forum.

Just search on straw, strawing, re-strawing or similar and you can find it.

For those challenged in degrees C- a nice straw color is obtainable from 420 to 460 degrees F, the range depends on the accuracy of your thermometer, time, metal, and phase of the moon.

It can be done in your "regular" oven; and re-done if it does not turn out to suit the first time.
Just re-polish to white and do it over.

[PhilOhio]

After absorbing John's fine strawing instructions, I thought I'd follow them a couple days ago. I needed to heat, slightly reshape, and retemper a later 1937 S/42 ejector which I had finally identified as the cause of an occasional forward-pointing stove pipe jam; with another round already properly fed mostly into the chamber. The ejector was very slightly loose in its recess. It needs to be facing all the way inward, in the bottom of its seat, under slight tension. Most of the time it functioned, but not always.

With all other modern spring stock I have worked with, when heat treating, you stop with the color blue. I thought this time I would stop at straw, as I assumed the Germans were obviously using an alloy where this was the right color.

But remember, something changed in 1937; early parts were straw and later ones were all blue.

Well, I wanted to get this ejector just right, and if the process would work, I would bead blast and straw the trigger the side plate also, whether or not this is "correct" for my serial number; it looks nice.

Anyway, I uniformly heated to a red color, slightly re-shaped, quenched, and polished the outside surface of my ejector. I then set it on its side on a clean cookie tin in my electric oven, with front glass window and strong oven light. I guess my cat wondered why I was hunched on the floor on a step stool, staring into the oven. Humans are weird.

I planned to throw open the door the second the straw color appeared, showing that tempering heat was uniformly distributed through the ejector. I set the bang-bang thermostat for 450 F and waited. Coils glowed, the oven heated, and the polished surface stayed silvery, bright steel color. No straw color, or any other color.

Then at the exact moment the thermostat clicked off, the color of the whole polished surface changed to deep electric blue. This took under two seconds, and there were no intermediary colors.

I opened the door and cut the heat instantly, let the part air cool (NEVER put oil on such a spring immediately), and installed it. 200 rounds or so has showed the temper was correct; nothing broke or took a set.

My question to you advanced Luger experts is this. Do you suppose that sometime during 1937 the Germans changed their ejector specifications to an alloy which tempers to a blue color rather than passing through a straw color at around 450F? ...and that post 1937 ejectors cannot be "strawed"? Might this have been a part of the process in deciding that the "strawing" of the other parts was, and had been, a waste of time?

Or did I do something wrong? I make a lot of coil and flat springs from scratch, and temper them. I think I know the process. But....?

I went back and looked at my color charts, to see if I had made a mistake. Nope, straw and the other colors must come first, and I don't think I could have missed them, staring at this thing under bright light, while the cat gave me the fish eye.

Anybody else ever try to straw a post-'37 ejector?

And for those of you with strange infrequent ejection problems, check your ejector for a slightly loose fit in its seat. If you know how, this can be fixed without replacing it or breaking it by trying to bend it cold. Never do that with any spring.

[rhuff]

Thanks to this article, I re-strawed an Erfurt mag catch/release. I didn't know what time frame was going to be involved, so I just pulled up my short stool in front of the kitchen oven and waited. It is a good thing that I live along, as not everyone would understand. I looked often, then realized that it was going to take a bit of time. Once I got the exact color that I wanted/needed, I applied a few drops of 3 in 1 oil to stop the process. I could not be more pleased. I just want to thank all of you folks that supplied this information, so I could accomplish the end product. Again, thank you.