1900 AE Heavy Wear Marks?
 

Extracted from the "Broken Parts Survey" thread - My broken firing pin guide and rear of frame where 'duckbill' hits -

http://forum.lugerforum.com/attachme...1&d=1356399039

http://forum.lugerforum.com/attachme...1&d=1356399039

I took it down today and took some more pics of any wear areas I could see...Hard to imagine that 7.65 Luger loads could impact the steel this much...But over 100+ years, I suppose it would add up...BTW: The bore is pretty worn...

Nice pics Rich, and you've shown the toggle ramps--an area I forgot for my list back at the other thread. What's up with the sharp diagonal edge to the wear at the bottom of ramp on left in last pic? Also, the ramp we see on the right appears to have been struck by a surface that was not square and parallel to it, otherwise, the wear marks' ends would be straight across. Can't quite tell from the pics if the edges of the ramps are mushroomed out, what do parallel jaw calipers or a mic say? Now I'm curious to see the knobs of the toggle, where they encounter the ramps while cycling.

The toggle does not hit the ramp at the bottom; it hits 1/8" up the ramp...The wear mark isn't straight across because the toggle knob edges are not parallel; the knobs are tapered...Like a truncated triangle (as seen from the top)...It tapers .004" over a .045" surface (the part of the toggle that hits the ramp)...There's no visible mushrooming, but my verniers tell me the ramp is .004"/.005" thicker where the impact marks are than below them, where there has been no impact...

Edit: The duckbill of the rear toggle does not show any undue wear or 'spread'...

OK, the taper of the toggles explains the way the marks are. But, looking at the last pic, what is giving the appearance of a triangular area of surface which looks undisturbed, it points up into the area of the ramp (pic left) that would be expected to be worn in a mirror image of the wear on its counterpart (pic right)--as if there is a chunk missing on the toggle knob that has hit it. Or is it a photographic artifact?

It's different because that knob has the 'toggle lock' in it, and there is a milled bevel on the bottom of the knob where it hits that ramp.

Great pictures.

Is it common for the firing pin retainer to hit the back of the frame. Looking at your above pictures it looks like mine and yours has the same looking mark where it hits the frame. Is this a major problem?

Attachment 30882

Yup that's the story, the wear pattern makes sense now. I'm not sure, since I've never seen a 1900 in person, that I've ever seen one's toggle train from this angle, much less noticed this aspect to the wear patterns this design configuration results in.

This leaves us, still, with the caveat to change over to fresh springs. Very graphic, and sometimes heartbreaking, evidence of what happens when the action is forcefully over-extended...

Yes, but likely cumulative. It takes repeated forceful blows to work harden a piece of steel, but the more forceful and frequent the trauma, the faster metal fatigue will develop if it continues--to the point of becoming so hard and brittle that crystallization occurs and one last whack causes it to shatter and fail. Check out the texture of the break on the spring guide above; it's not torn, but shattered/snapped. I'm not knowledgeable of how to assess the damage/progression if it is noticed before failure of a part. I consider a crack a failure, and a break a catastrophic failure, even though both are catastrophic, as far as collectors are concerned. I think up to a certain point, further service will be OK, but after that point, continued use would be dangerous to the part, and perhaps to the user. But I don't know how that could be established. Maybe X-ray?

The pieces of my guide are somewhat mystifying...I don't see how it could work-harden...It doesn't flex, or twist, or bend...It travels in a straight line and [theoretically] doesn't even move (in relation to the parts around it)...

My pieces do show some crystallization, but the loose piece was reciprocating back & forth and the end & cavity have been peened by that motion so it's hard to tell what happened...

Hopefully, someone more familiar with these models can add their comments...

Pic attached...

On the mainspring: There is a guy on eBay who advertises NOS flat mainsprings -

http://www.ebay.com/itm/EARLY-GERMAN...-/160944562499

I bought one a couple months back, when I thought mine was broken (it's not), and it looks new, just some very slight rust freckles...Doesn't look home made, and doesn't look like it was made lately either...It looks original...

I was going to keep it as a spare, but maybe I'll put it in...Just in case I decide to shoot it...

He seems to have quite a few of these...They're on eBay almost every month...

I did ask Wolf if they made the flat mainsprings...they don't...

I also ordered some 1095 spring stock to attempt making one myself...For emergencies...But the Luger flat mainspring is a weird gauge; not Metric and not Yankee either...

Hmmm! x-ray. That would be cool to see on some of my aparts, especially the rear toggle that already has some cracking. I have access to a digital x-ray machine at work. We x-ray welds on pressure vessels and other various things. This would be a nice example to try and x-ray. Curious if any inclusions would be found on these old pieces.

I just looked it up, and work hardening occurs with the molecular rearrangement of the lattice in the material. These 'Dislocations" add up until the point of crystallization. I included mechanical pounding (intermittent compressive force) in the list of ways work hardening is induced, the others being torsion and tension, as you mentioned, all of which forces cause molecular dislocations. Work hardening is done on other materials such as copper and aluminum, in their transformations into sheets, wire, etc, which are not able to be hardened by heat treat, as steel is.

I would wonder that at sometime in its life, it was fired without the main spring properly assembled to the toggle train. this would tattoo those marks in for sure. John

To me it looks like a fatigue type failure due to the firing pin retainer striking the rear of the frame repeated times.
Ed

I have a tool for measuring spring tension...If I can figure out how to attach it to the toggle in such a way that it will show an accurate read, I'll try it with the old [present] mainspring vs the NOS mainspring, both installed...

Edit: Hmmmm...Not as difficult as I thought...[pic below]...I can hook it on the toggle and pull to full reach...

I get a repeatable 10 pound reading with the present mainspring...Perhaps not the most accurate way to do it, but for comparative tests, it should show any difference...I realize that there is no way to know if this is the original mainspring or a recent (or an old) replacement...It may have been added after all the pounding was done to the action...

Edit: NOS mainspring installed measures 9 pounds on my spring tension gauge, repeatable...

So either I have a good mainspring already installed, or someone has been firing either hot loads or very many of them...

Pic 1 - Luger + spring gauge
Pic 2 - Measuring installed/old mainspring
Pic 3 - Installing new/NOS mainspring
Pic 4 - Mainsprings = new, old front; new, old rear
Pic 5 - Measuring new/NOS mainspring

I would welcome anyone with a 1900/1902 to 'measure' their toggle tension so that I could compare it to mine... :)

Easy enough to do: Take a 9, 10, or 11 pound weight, tie a piece of string to it, tie the other end around the toggle of an unloaded, cocked, un-magazined 1900 and hold it by the barrel [barrel pointing up] with the weight hanging down and see if it racks the toggle back to the stop... ;)

I'm curious about that contraption you made up. I'm thinking some kind of fish scale would work. I think I would like to know what mine has. When torn apart, the leaf spring in it doesnt seem to have much tension at all. But, I never knew if it was meant to be that way. I know it does not have anything close to the one I have with a coil type mainspring.

Give me a closeup pic of how you have it hooked into the toggle. I would hate to damage it while doing this.

The hook/grabber thingie Rich made is brass, so other than imparting a little bit of its material to the surface of the toggle, it can't do any damage. One can gently remove the smeared on brass with oiled 0000 steel wool.

I think the angle of pulling the measuring device relative to the pistol frame may be important for trading data back and forth. With the same pistol, same angle, but different springs, you'd get a data set which would enable you to compare the different springs. If we standardize the angle at which the pistol is mounted in addition to the angle relative pulling is done, then I think we can swap info. This is a vector force, and although I haven't worked it out specifically, I believe the angularity must be duplicated to bring individual pistols' measurements into line with the rest.

Since I don't have the 1900, I don't know, but is it possible to install a later coil spring and guide temporarily for shooting?

This thing is an electricians tool for measuring spring tension of brushes on motor armatures...I had it from my old job and use it to set trigger 'pull weight' on .45 autos mostly...

I don't know what a fish scale even looks like... :rolleyes:

Go back to the first pic; the gauge has a square hook that I hook into the slot/cavity of the toggle knob...The hook is 5/32" brass rod...

Edit: Thor was right about these flat mainsprings...The more you do them, the easier it gets... :D

Postino:
Easy enough to do: Take a 9, 10, or 11 pound weight, tie a piece of string to it, tie the other end around the toggle of an unloaded, cocked, un-magazined 1900 and hold it by the barrel [barrel pointing up] with the weight hanging down and see if it racks the toggle back to the stop...

Well, I took a 10 pound weight and tied a string around the same area you were pulling from on the toggle. I tried to hold the gun at the same angle as yours as seen in your pictures. My toggle did not fully pull all the way back with that weight and that method. I wanna get something that will give me an actual measurement. But I think it aint going to be much more than 10 pounds. Cause it comes close to being pulled all the way to stop, but just a hair shy.

Glenn,

I think postino's talking about two different methods, and the one with the gun at that angle in the pic would be for the scale/meter thing he's pulling it with. Loops of string around the toggle knobs and a weight that can be varied on the other end would be an entirely second method--and I think when he says barrel pointing up, it means straight up. You'd be hanging onto the barrel and dangling the weights from the toggle knobs until they rack back to the limit of the cycle. This way, gravity is doing its thing at the same angle you'd apply the force to draw the toggle back, relative to the pistol itself. One could use a fish scale or similar, one end fastened to the floor, in line with the toggle strings. Loop the loops, pull up on the barrel, and take note of the reading on the scale when the toggle moves all the way back. I guess you could do this in a horizontal setup, too; but make sure it all lines up the same way as the dead weight setup...or clamp the barrel in a padded vise and pull on the far end of the scale, etc. etc.

I have a 1900 AE shooter and have been following this thread with interest. I use reduced loads with light bullets in an effort to prevent damage. Regarding the method of measuring spring tension:
Would it not be more accurate and consistant to measure by inserting a soft aluminum or brass rod in the barrel and measure by pushing it against a scale?
KFS

Yes. :)

Sounds good to me! I don't have a scale. :D

OK heres my new update on my data. I got a digital fish scale and put an aluminum tie wire on the end to wrap around the toggle in the same location that Postino did. I clamped the grip of my gun to were the fron portion of ht egrip was at the 90 degree orientation from the table. Trying to pull with the scale parallel to the table as much as possible. I left an empty magazine in the gun so a had a stopping point once it clicked in the open position. My readings averaged around 10.5 to 11 lbs just before it cicked into the open position for the toggle.

Excellent! :thumbup:

Should we start a chart??? :D

Or maybe a poll??? :p

(You should not attach any significance to the angle of the Luger...I did it that way to get a good camera shot...And that was where the flats of the gripframe were...) :rolleyes:

I'd be interested in knowing the rate of tensioning of an old-model flat spring and a new-model coil spring.

--Dwight

I don't have a scale or a 30 cal squib rod long enough, so I tried a 1/4" wood dowel and my mechanical spring scale...It doesn't work...There is too much friction from the dowel sliding down the barrel...I got wildly erratic results, up to 16 pounds...(first pic below)...The pull was very 'jerky'...

If you're doing the rod in barrel 'push' method using a postal or bathroom scale, remember that those are 'zeroed' using gravity as a constant...If you use these, put the scale on the floor and push down against it...(Not from the side)...But I think friction would still affect the results...

Good idea; I re-tried the 1900 AE w/flat spring held in soft vise by the trigger guard, and then the 1937 S/42 coil spring held the same way...(second and third pics)...I got pretty much the same spring tension at full toggle travel; 10 - 10 1/2 pounds for the S/42...

I straightened out the clamping [no angle] so y'all wouldn't get so confused...It made the pic bigger...And I left the magazines out...

Interesting comment: Although the final spring value was essentially the same between the flat vs coil spring, the 'feeling' of pulling the toggle back was markedly different...I can't really describe it, except to say that if I was blindfolded, I would be able to tell which pistol was which by the spring pull...

Well postino I got to agree with you. I took my other luger this morning with a coil type mainspring and I also got right around 10.5 almost 11. But it takes a more of an initial pull to get the toggle to start moving. Once It passes a certain point and start pulling slowly to the point where the hold open catch catches, it reades almost the same as my 1900. Weird cause I sure though it would be a much higher reading. I think its just that initial point of getting the spring to start compressing that just feels totally different that the leaf spring that doesnt have that kind of action.

The coil spring Luger has a "L" shaped 'recoil lever' between the coupling link and the mainspring which the flat spring Luger does not have. I think this changes the feel of the pull...It may even provide a mechanical advantage by providing leverage that the flat spring does not enjoy...

It's been 37 years since I took all this stuff in college, and trying to plot vector diagrams to determine mechanical advantage is beyond me...

IIRC, springs are rated by the amount of weight required to compress a spring one inch...So a 36 pound mainspring should take 36 pounds to compress it one inch...

I was mildly interested in seeing how much pressure it would take to deflect the flat spring one inch...(Pic attached)...

It took 6 pounds...Unfortunately, this has no relation to anything in the real world as pertains to this discussion, as the Luger grip frame has several points that touch the mainspring and affect the mechanical advantage...

But it does give me a base to compare other mainsprings against...Without installing them... ;)

I have been told that some gunsmiths have made replacement flat springs by milling a single piece of spring steel to the required size & shape...It would be interesting to compare those with the OEM two piece Luger mainspring readings as detailed in this thread...