Borchardt-Luger Controversy

[Johnny Peppers]

Dwight,
You are exactly right in that as long as all the parts of the toggle assembly remain in the same plane, the toggle assembly will not unlock until the toggles bump the ramps on the frame. In fact it only takes the light initial pressure of the recoil spring to keep the toggle assembly in alignment. If the toggle knobs are allowed to raise only a fraction of an inch, which they can do without the breechblock moving, the toggle assembly is free to break at that point. The firing pin spring as well as the recoil spring work in conjunction with each other to keep the toggle assembly held in the proper plane at initial ignition. Also remember that the spring tension of the ejector riding on the breechblock also aids the breechblock in remaining in the proper position even if the two other springs are removed.

[Jerry Harris]

May this thread rest in peace -- but not without a post-mortem, as follows:

I believe <everyone> who posted here knew from the beginning that the Maxim/Borchardt/Luger toggle cannot remain locked against the primary recoil shock except by its geometry, that is by having the center pivot lowered just enough to want to break downward against the receiver (barrel extension) sides which block it solidly until the knobs are bumped upward against the ramps.

Many hundreds of words (all worthy and well-reasoned) were expended at cross purposes with Kyrie because the function of "holding the toggle closed" or "holding the breech block in battery" has two distinct meanings. Meaning No.1 is holding the toggle closed against small handling forces before firing, and meaning No.2 is holding the toggle closed against a huge rearward force just after firing. Both are design necessities.

Kyrie seemed to think that those people describing (correctly) how the recoil spring helps significantly in holding closed against small disturbances (No.1) were somehow denying or overlooking the fact that a depressed pivot is required to hold closed against main recoil (No.2). That's why there were so many go-rounds.

Kyrie was right in pointing out that a slowly lowered toggle, robbed of all kinetic energy, stalls and won't complete the cocking cycle with either flat or coiled recoil spring. But Johnny and others were right in pointing out that once the action <is> closed and cocked, the preload in the recoil spring is really the only significant force preventing the toggle from being jarred into breaking slightly the wrong way again before the user decides to fire the gun, resulting in a dangerous premature blowback.

One last thing. Many toggle mechanisms used in industry, such as clamps and locking pliers, hold themselves closed by jamming and deflecting a little as they go over center. The Luger toggle doesn't do that, as can be checked by removing the cannon (here we go again), taking out the firing pin spring and closing the breech on a spent shell casing. The breech block still has a little clearance, and the toggle knobs will easily move away from locked position that critical small amount unless an external force keeps them down.

I think long, redundant discussions of how the Luger was developed and how it works are at least as interesting as long, redundant discussions about the minutiae of collecting. So my thanks to Kyrie, who started it all, and everyone else who contributed.

[unspellable]

One small point. When the toggles are slowly lowered to the in battery position and released a bit before arriving in battery, the action may or may not finish closing depending upon the particular pistol and recoil spring at hand. I have more than one of either example in my collection. The general trend in new model Lugers (with exceptions)is for the 9 mm to close and the 7.65 mm to remain open due to differences in the recoil spring.

[Herb]

DANG, youse guys really get into how things work!
Who wants to be the first to explain to me how in heck those Phasers that Worf and Picard use work? <img src="graemlins/roflmao.gif" border="0" alt="[hiha]" />

[Edward Tinker]

Faith Herb, they believe they work, so they do.

[Big Norm]

Man, am I glad that we got to a separate page. It got boring scrolling back and forth on this great discussion. I lost track more than once on the topic. I have a problem on an artillery that won't close the toggle and has a loading/unloading problem. The toggle closes to within about an eigth of an inch of full closure. At first I thought it was dirt a little notch in the barrels cone that the extractor fits in at closing. Now I am wondering if this is a problem with the mainspring? I am sorry that I am a bit OT but this is something that has been hanging me up for a long time.
Big Norm
<img src="graemlins/c.gif" border="0" alt="[ouch]" />

[Lugerdoc]

Norm, I agree that your problem does sound like a recoil spring or connector link problem. Do you have the same problem using different magazines? Tom H.

[Dwight Gruber]

Norm, is it that your Artillery won't go into battery while working the action (i.e. you can close it with a push down on the toggle), or can you not actually close the breech?

I had the latter happen to me at the range one day (panicked me pretty good, I was shooting a matched byf41 which I intend to sell), I could not get the breech to close by about an eighth of an inch for love nor money, it was a hard blockage.

When I got home I stripped the gun down and discovered (to my great relief) that the striker spring pin at the back of the breechblock had rotated about an eighth of a turn, and that was what (somehow, I still don't know how, exactly) was blocking the last bit of breechblock travel. Rotated it back into position, worked perfectly.

Frankly I'm very sceptical of a spring problem here, I am in the camp which has it that the springs don't have very much to do with the initial opening or final closing forces on the Luger action. That being said, I hope my situation helps you out, good luck in tracking down your problem in any case.

--Dwight

[Dwight Gruber]

[quote]Originally posted by Johnny Peppers:
<strong>Dwight,
The firing pin spring as well as the recoil spring work in conjunction with each other to keep the toggle assembly held in the proper plane at initial ignition.</strong><hr></blockquote>

I thought I could let this topic ride, but its been bugging me and I just have to give it one last go.

Remove the cannon from the frame and move it around, applying inertially tangential forces to the toggle train. The toggle stays closed. It is clear that the striker spring provides all the force necessary to keep the toggle train in its locked position, as a connection with the main recoil spring is nonexistent. The recoil spring has no, repeat -no-, effect or function in keeping the toggle train in its proper plane at rest.

--Dwight

[Doubs]

[quote]Originally posted by Dwight Gruber:
<strong> Remove the cannon from the frame and move it around, applying inertially tangential forces to the toggle train. The toggle stays closed. It is clear that the striker spring provides all the force necessary to keep the toggle train in its locked position, as a connection with the main recoil spring is nonexistent. The recoil spring has no, repeat -no-, effect or function in keeping the toggle train in its proper plane at rest.
--Dwight</strong><hr></blockquote>

With the striker in the cocked position - as it would be for firing - the force of the firing pin spring is actually pushing back against the breechblock and it takes VERY LITTLE momentum to cause the toggles to pop up. The striker spring pressure actually HELPS to push the toggles up. (In fact, the striker spring does more to keep the train locked when it's NOT cocked as the train has to overcome the drag of the sear and the striker spring pressure to reach the "toggles broken" point.) Turn the cannon over and tap the top of the receiver where the date is normally stamped against the ball of your palm. If the pistol had been designed for zero recoil spring tension on the toggle train when in battery and with only the striker spring pushing back on the train, the design would never have flown and it would be a long forgotten footnote in the history of firearms.

There is NO POINT in the cycling of the action from cocked and locked through opening, ejection and chambering a new round that does not have recoil spring pressure applied to the train. Even with the striker uncocked, there is recoil spring pressure being applied. It's part of the design. If that wasn't true, there wouldn't be pressure of varying weight applied to the train at ALL times by the recoil spring.

[Lugerdoc]

Doubs, Good analysis. I concur. Tom H.

[Kyrie]

Hi Doubs!

[quote]Originally posted by Doubs:
<strong>
With the striker in the cocked position - as it would be for firing - the force of the firing pin spring is actually pushing back against the breechblock </strong><hr></blockquote>
Yes sir, the net effect is as if the striker spring were directly acting against the breechblock. But in reality the striker spring is actually not pressing directly against the breechblock. Rather it is pressing forward against the inside front surface of the striker channel in the striker, and rearwards against the breechblock end piece, which in turn is pressing rearward against the breechblock.

[quote]Originally posted by Doubs:
<strong>
and it takes VERY LITTLE momentum to cause the toggles to pop up.
</strong><hr></blockquote>
Quite right! But whatâ??s happening here is actually quite complicated.

With the striker held at the cocked position the pressure exerted by the striker spring is bi-directional. It is exerting pressure forward against the striker, and rearward against the breechblock (via the breechblock end piece). So long as the toggle pivot point is below the centerline of the toggle train this rearward striker spring pressure on the breechblock serves to retard upward motion of the toggle knobs. But as soon as the toggle knobs have been raised enough to bring the toggle pivot point above the centerline of the toggle train and the rigidity of the toggle train is broken, then the compressed striker spring will fling backwards the breechblock, causing the toggle knobs to jump upwards.

[quote]Originally posted by Doubs:
<strong>
The striker spring pressure actually HELPS to push the toggles up. </strong><hr></blockquote>
Yes sir, it does, but only after toggle pivot point is above the centerline of the toggle train. Conversely, the striker spring opposes forward movement of the toggle train once the teat on the striker contacts the sear and the striker spring begins to be compressed between the inside front surface of the striker channel in the striker and the breechblock end piece.

[quote]Originally posted by Doubs:
<strong>
(In fact, the striker spring does more to keep the train locked when it's NOT cocked as the train has to overcome the drag of the sear and the striker spring pressure to reach the "toggles broken" point.) </strong><hr></blockquote>
Here I have to respectfully and cordially disagree. When the striker in not cocked, it is forward of the sear and there is no sear drag - as there is no contact with the sear. Also, the striker spring is not compressed by the rearward movement of the toggle train. Rather it is compressed by the forward movement of the toggle train after the teat on the striker contacts and is held to the rear by the sear - an uncompressed striker spring provides no spring pressure.
That said the striker, during rearward movement of the toggle train, must pass by the rear of the sear and to do so must push the rear outward. This outward motion of the rear of the sear is resisted by the sear spring, so the inward pressure on the rear of the sear exerted by the sear spring must be overcome by the force being used to draw the breechblock (and the striker it contains) to the rear. Thus the rearward motion of the toggle train is not inhibited by either the striker spring or sear drag, but rather by the sear spring which opposes the movement of the outward movement of the sear to clear the path of the striker as the strike moves to the rear.

[quote]Originally posted by Doubs:
<strong>
Turn the cannon over and tap the top of the receiver where the date is normally stamped against the ball of your palm. If the pistol had been designed for zero main spring tension on the toggle train when in battery and with only the striker spring pushing back on the train, the design would never have flown and it would be a long forgotten footnote in the history of firearms.
</strong><hr></blockquote>
This is true, and I donâ??t think anyone has suggested otherwise.

The point I was making (and this seemed to gotten lost in the discussion fairly quickly {wry smile}) is that the pressure of the main spring pushing the toggle train forward during firing becomes equal to or less than the pressure of the striker spring as the striker spring resists compression during forward movement of the toggle train during firing. At this point in time during action cycling the force acting to bring the toggle train forward is only the momentum of the toggle train, imparted to the toggle train by the main spring before the main spring force was equaled or overcome by the resistance of the striker spring.

[quote]Originally posted by Doubs:
<strong>
There is NO POINT in the cycling of the action from cocked and locked through opening, ejection and chambering a new round that does not have main spring pressure applied to the train. Even with the striker uncocked, there is main spring pressure being applied. It's part of the design. If that wasn't true, there wouldn't be pressure of varying weight applied to the train at ALL times by the main </strong><hr></blockquote>

Again, quite true and not something Iâ??ve ever disputed. Mainspring pressure on the toggle train exists throughout the movement of the toggle train. But this mainspring pressure is countered by, and becomes mechanically insignificant, when the toggle train returns forward sufficiently for the striker spring to resist the forward movement of the toggle train.

Warmest regards,

Kyrie

[unspellable]

So long as we are having this debate about the details of which spring does what, let's get the designation right. The striker spring is the mainspring. The recoil spring is NOT the main spring. In any breechloading, caplock, flintlock or snaphaunce firearm, the mainspring is the one that makes it go bang. Hence, in the Luger the striker spring is the main spring. All of these firearms have a mainspring, the majority do not have a recoil spring. In some itty bitty pocket pistols, the mainspring and recoil spring become one and the same spring. I am referring to English terms here without regard to German ones.

It's probably better to refer to them as striker spring and recoil spring and side step the confusion. Referring to the recoil spring as the main spring probably happens because it is the biggest spring. But keep in mind that Thor, unlike us mere soft pawed mortals, is in the habit of shooting the cannon with no recoil spring present. But he is still using the striker or main spring.

The recoil spring exerts a closing force on the toggle train at any and all positions. In the last stages of closing, the striker spring presents an opposing force. It then becomes a balancing act as to which will exert the greater force. Which one dominates depends upon the individual pistol and spring set. Momentum does play a significant role in the final stages of closure, paricularly with a light recoil spring. If deprived of momentum by holding the toggles and allowing them to slowly close, some Lugers will close on spring forces alone, some will not close. Keep in mind this only counts when loading a cartridge. The principal difference is in the strength of the recoil spring.

Minus the recoil spring, the striker spring will tend to keep the action closed when it is in battery and cocked since the "knee" is past center. This is a rather small force though. If not cocked it will have no influence.

When in battery, the closing force of the recoil spring is required to insure that the action is not opened by the random forces of handling or dropping the pistol. This force is of liitle or no significance in keeping the action closed at the time of firing. The back thrust tneds to hold the action closed due to the "knee" being below the center line of the front and rear toggle pins.

In contrast, the Erma Luger look alikes are blowbacks, the knee never goes below the center line and the spring force is absolutely required to keep the action closed in handling. Strangely enough, the spring force is not very significant at the time of firing. here, the inertia of the breech block and toggle train tend to oppose opening and slow it down to the point that the bullet has left the barrel and the pressure has dropped before the action has opened far enough to expose more than the web area of the case. The spring forces are then significant for decelerating the action while momentum opens it the rest of the way.

The spring force is not significant in holding the action closed at firing in the blowback because the backthrust is on the order of several hundred pounds while the force of the spring is a few tens of pounds. The case expands and drags on the chamber walls providing more resistance to opening than the spring does.

[Doubs]

As regards the terminology of main spring and recoil spring, Unspellable is, of course, absolutely correct. I know better and should have used the terms correctly. I have edited my post as needed to make it right.

Kyrie is also correct that compression of the striker spring doesn't occur until the toggles move from the "broken" position to the locked position. However, as he also acknowledges, there is friction between the striker and the sear as the toggles raise.

I can't speak for anyone else but this thread has caused me, at least, to consider the working of the action, and the forces involved, more closely than I otherwise would have. It's been an interesting discussion..... and maybe not over yet! [img]smile.gif[/img]

[Kyrie]

Hi Unspellable!

Iâ??d disagree only with your terminology :-)

Seriously, and in the interests of clarity and of comradeship, may I suggest we use the terminology from the â??Parts and Disassemblyâ?� page on this Forum? I think we may both disagree with the terminology used there, but that terminology has the advantage being easily accessible to all, and is complete with a parts diagram so folks who havenâ??t spent a lot of time inside a Luger can at least see which parts are being discussed.

Just a suggestion :-)

Warm regards,

Kyrie
Moderator - Cruffler_Forum on Yahoo Groups
"The flame free C&R Forum."

[Kyrie]

[quote]Originally posted by Doubs:
<strong>I can't speak for anyone else but this thread has caused me, at least, to consider the working of the action, and the forces involved, more closely than I otherwise would have.</strong><hr></blockquote>

Hi Doubs!

You speak for me as well :-)

The Luger is a real study in the redirection of force, sometimes around several corners! Perhaps we should discuss the linkage that turns a press on the trigger to the release of the firing pin. The trigger to firing pin linkage is just bizarre, and would please Rube Goldberg ;-)

Warm regards,

Kyrie
Moderator - Cruffler_Forum on Yahoo Groups
"The flame free C&R Forum."

[Big Norm]

Tom and Dwight,
Yes, I have tried different mags both new and old. I am able to slap the toggle shut. But the artillery fires about 50% of the time properly and the rest of the time it either stove pipes or the spent cartridge is not pulled out of the chamber. Sometimes the gun is not cocked and my simple moving the toggle back about a quarter of an inch cocks it. Because the spent casing often stayed in the chamber I was focusing on dirt in that little notch above the barrels cone that the extractor fits into. But that does not seem to be my answer.
Big Norm

[unspellable]

Hi Kyrie,

Recoil spring and firing pin spring as per the parts list suits me. However I notice the associated numbers do no seem to match the exploded drawing. Apparently the numbers do match one or another of the original Luger manuals. Maybe we need a third column of numbers to match the exploded drawing.

If anybody starts a discussion on the trigger linkage, make it a new thread.

[Jerry Harris]

Kyrie,

In response to Doubs, you wrote (in part):

"...the striker spring is not compressed by the rearward movement of the toggle train. Rather it is compressed by the forward movement of the toggle train after the teat on the striker contacts and is held to the rear by the sear..."

The second part of this exerpt is good as gold, but the first part is not borne out by the realities of the relationship between the toggle action and the striker. In fact, the striker spring is progressively compressed throughout the entire rearward (opening) movement of the toggle train!

This can be observed by pushing out the rear toggle pin and sliding the toggle/breechblock assembly out of the receiver (barrel extension). One can then see that there is a projection or "ear" at the front end of the forward toggle link which engages the forward end of the striker lug (teat) and begins to cam it rearward, relative to the breechblock, as soon as the toggle knobs have raised by 1/16 inch or so. This camming continues throughout the breech opening, and is of course accompanied by increasing compression of the firing pin spring.

The analytically inclined person will wonder at once why the ear was provided, since its action has nothing to do with the actual cocking of the striker in preparation for firing! I have contemplated at some length why the function exists and discussed it off-line with Johnny Peppers. Between us we came up with a couple of plausible reasons, but perhaps they are best reserved for another time.

[Doubs]

Jerry, GREAT observation! As many times as I've manually compressed the firing pin spring by flexing the breechblock and middle link and I completely let that fact slip my mind.

My thought would be that compression of the firing pin spring under recoil is necessary because the recoil spring power plus the momentum of the mass of the train wouldn't be enough to compress the spring reliably - maybe not at all - through engagement of the sear near the end of the cycle when recoil spring pressure would be nearing it's lowest point.