Draw lines (Witness marks)

[Jim Keenan]

A few days ago, there was a brief mention about draw lines, sometimes called "witness marks" on barrels and receivers, specifically on the Luger pistol. These are the short lines on the bottom of the barrel shoulder and the receiver 180 degrees from the sight line. Apparently some writers on the Luger have stated that these were put on after the barrel was installed.

That was not the case; the draw lines were put on before assembly because they were used to ensure both the correct position of the front sight and to ensure that the barrel lined up with the receiver in assembly. As the name indicates, they show the point to which the barrel must be "drawn up" (screwed in) to allow the front sight to line up properly.

I am taking certain liberties here; the order of the operations may have varied, but this is basically the way the draw lines were used in building a Luger.

When the receiver was partly finished but faced and threaded for the barrel, it was placed in a fixture and a special jig holding a chisel shaped tool was used to make the receiver draw line at the exact bottom of the receiver beside the barrel hole. All receivers were so marked. The line was marked deeply enough that it would not be obliterated in polishing and bluing

After the barrel was partly finished but the front sight base had not been machined out of the "ring", the shoulder was cut and the barrel was threaded. Then a special female gauge was run onto the threads until it stopped. The gauge had a slot into which another chisel shaped tool was inserted and then struck, making the barrel draw line on the barrel shoulder. This draw line was also struck deeply enough to survive polishing and bluing.

The barrel was then set up for machining of the front sight base, using the draw line to ensure the base was in the right place (180 degrees away from the draw line). The barrel was then finish machined, drilled, rifled and crowned, the breech end was finished and the chamber cut. The extractor cut was then made, again 180 degrees off the draw line.

When both receiver and barrel had been finish machined, the barrel was clamped in a fixture and the receiver screwed on using a special wrench until the two draw lines matched perfectly. The assembly was mated to a grip frame, fitting was done, and all three parts numbered to ensure they remained together during finishing and bluing. Other parts were fitted and numbered also while the gun was "in the white". The gun was then disassembled (all but the barrel-receiver assembly), given a final polish and rust blued or tank blued, depending on the period.

Spare barrels also were fully finished and had draw lines, so replacing a barrel became a simple matter of screwing it in until the marks lined up. Usually, the line up was perfect. If it was not, the barrel shoulder could either be trimmed down a bit at the rear or "rolled" to widen it. Either way, the barrel would be of the proper tightness when the draw lines matched. I believe spare barrels may have been short chambered to allow headspace to be set with a reamer, as was done with rifles, but I have no confirmation of that, and tolerances should have allowed pre-chambered barrels to work without a problem.

Jim

[Ron Wood]

Jim,
Excellent account. This topic was the subject of much discussion back on 02-23-2003 in the "Navy Luger" forum that started with the tread titled "A Learning Experience...". Look it up an then get back to us with your thoughts on the discussion.

[Jim Keenan]

Hi, Ron,

Thanks for the tip. I was not a member at the time and had not seen that. I will stand by the process I described.

Despite reams of paper on the precision of the German arms industry, they were really not any more precise than anyone else. (Look at the variation on the plug gauge bore diameter readings of Luger barrels.) Since absolute parts precision was not possible, selective fitting was used, as it was used by US arms makers as well, and the parts numbered.

The Luger was, in fact, fully assembled and parts fitted and numbered, then taken apart for final finish and bluing, and heat treatment of some parts. (The barrel was NOT removed.) Then it was reassembled. That was the reason for the number, to make sure fitted parts stayed together.

They did the same thing with the K.98k, with the result that rifle production was slow and inefficient by US standards.

The statement that the draw line was used in determining the position of the front sight is true, but the machining of the front sight was done as part of barrel making, not after assembly. In every arms factory in the world, barrel production was an independent process, with barrels produced separately from receivers, and they did not get together until they were put into the sub assembly. When a Luger barrel was made, there was no way of knowing whether it would be installed in a pistol or set aside as a spare. It was finish machined in the white, then put in a rack to be taken to the assembly benches.

If a pistol shows draw lines that don't line up (within a tiny margin of error - the match was done by eye) then the front sight should not line up either. A slight misalignment of the sight is easy to overlook, but I would bet on the draw line being right. If in doubt, what I do is to clamp the receiver (without the grip frame) on a steel flat, then lay a 12" steel straight edge across the sight at right angles to the barrel. This will show any sight misalignment, and it can be corrected easily by turning the barrel in or out a tiny bit.

Jim

[Dwight Gruber]

Jim,

Please document the source for your description of Luger construction, thanks.

--Dwight

[saxman]

Why is it that headspace is not mentioned in this elaborate theory? IMO it is not likely that witness marks would be placed before barrel installation and headspacing. It is a simple fact that if you take three barrels with witness marks and install them one after another into a given frame, with a given torque value, the witness marks are going to miss the mark on the frame just as often as they hit it. This critical assembly would not be left to the chance of the marks lining up when the proper torque was reached, coincidental to the headspace being also correct at that precise point. I believe it is much more likely that the front sight and extractor cuts were made after barrel fitting, gauging, numbering and witness-marking.

[Ron Wood]

Saxman,
If I might also direct your attention to the discussion on 02-23-2003, you will find just about every consideration and theory on the function of witness marks has been put forth in that string. It is interesting reading and perhaps you will find something you had not considered or you may be able to add yet more to the subject. Just use the "search" function at the top of the page and search the "Navy Luger" forum using the subject "A learning experience".

[Strider]

Jim,
There is another thread that addresses this issue that was posted by Dwight that was realy informative. It was dated 04.02.03 and called "Witness marks and barrels - preliminary conclusions" in the general discussion area. Take a look at this one also.
Sid.

[Ron Wood]

Sid,
Thanks for remembering Dwight's excellent report. I had forgotten where I saw it. It is a great piece of work.

[Edward Tinker]

Here are several threads:

http://forums.lugerforum.com/lugerfo...=000618#000000

http://forums.lugerforum.com/lugerfo...=000599#000000

http://forums.lugerforum.com/lugerfo...=000580#000000

[Navy]

It seems my original post 8really* opened a can of worms! I am very pleased to have had something to do with initiating this very informative discussion.

Tom A.

[Navy]

</font><blockquote><font size="1" face="Verdana,Tahoma,Arial,Helvetica,Geneva">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Originally posted by Tom A:
<strong>It seems my original post "really* opened a can of worms! I am very pleased to have had something to do with initiating this very informative discussion.

Tom A.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">

[Jim Keenan]

I wonder why anyone would put "witness marks" on the barrel and receiver if they were already installed and lined up. What purpose would they then serve? Also, the theory that the barrels were installed and then finished does not quite explain the picture I have seen somewhere of an assembler with a rack of completed barrels with finished sight bases.

Another advantage of draw lines is that the chamber can be finished and the headspace will be correct, since the barrel will always line up in the right position. Any minor deviation will not be enough to create a headspace problem, whether the barrel is to be installed on a pistol or is to be set aside as a replacement barrel.

In addition, the fact that the draw lines on barrel and receiver do NOT always line up perfectly would show they were not made at the same time. If the purpose was simply to show the original barrel position, they would have been made with the same tool at the same time, with a single blow. That is obviously NOT the case, as a close look at several Lugers will show.

I stand by my statement on the reason for and use use of draw lines.

As to the order of work, Walter's description of the inspection and acceptance marks being put on after the gun was blued is certainly wrong. If that was done, those marks would show bright metal where the bluing was cut through. While I am sure others here have seen far more original finish Lugers than I have, I have never seen any inspection/acceptance mark that was cut THROUGH the bluing. In fact, they are usually partially buffed out by the final polishing prior to bluing. Those marks, like the numbers, were put on while the gun was in the white.

(Where the law allowed, proofing was almost always done "in the white" so that if a barrel failed proof, time had not been wasted on bluing it.)

Parts would have been gauged, inspected and marked with inspection marks (if required) as parts, in the white. They would not have been inspected after bluing or, again, the marks would cut through the blue, which they do not. Nor were they inspected by the assemblers since then every assembler would have had to have a full set of gauges, an unlikely situation.

Assembly numbers, likewise, were put on before bluing; they never show bright metal and always show signs of buffing and bluing.

Is it too much to ask that collectors have some knowledge of the way factories work? Or are we supposed to assume that the Luger was a heavenly gift, made by divine intervention rather than by the common production techniques of the day?

If anyone has a Luger in which the draw lines are more than a degree or so off, I would suggest checking the front sight for alignment. Either the barrel was not installed properly or the original barrel was taken off and then it or another barrel was installed improperly. This is not always easy to see just by sighting the gun, but a straight edge will tell the story.

Jim

[Edward Tinker]

</font><blockquote><font size="1" face="Verdana,Tahoma,Arial,Helvetica,Geneva">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Is it too much to ask that collectors have some knowledge of the way factories work? Or are we supposed to assume that the Luger was a heavenly gift, made by divine intervention rather than by the common production techniques of the day?</font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Jim, having a rough night?

I think that others have other theories, as you do, and although yours makes sense, the theory that the witness marks were placed for later turning of the barrel to the correct place, also makes sense?

Ed

[Dwight Gruber]

Jim, I suggest that you search out and read the discussion entitled "Witness Marks and Barrels--A Preliminary Conclusion", as it examines, by actual observation of real Lugers, evidence which relates to (and refutes much of) what you have written in this discussion.

I also strongly recommend you buy a copy of "German Small Arms Markings" by Joachim G�¶rtz and Don L. Bryans, Walsworth Publishing Co., 1997. It includes translations of the actual Army contract and instructions for inspecting, marking, power proofing, and other elements relating to the constructing and acceptance of the P-08.

Jim Keenan has written--

"A few days ago, there was a brief mention about draw lines, sometimes called 'witness marks' on barrels and receivers, specifically on the Luger pistol. These are the short lines on the bottom of the barrel shoulder and the receiver 180 degrees from the sight line. Apparently some writers on the Luger have stated that these were put on after the barrel was installed."

'Some writers' have this directly from the Army instructions for marking the P-08. These instructions are detailed and quite unequivocal; failure to follow the terms of the contract could havae resulted in a fine.

Your description of Luger barrel construction and installation (I have not quoted here) is completely at odds with the official Army instructions.

"Spare barrels also were fully finished and had draw lines..."

The replacement barrels examined and reported did not have witness marks.

"I wonder why anyone would put 'witness marks' on the barrel and receiver if they were already installed and lined up. What purpose would they then serve?"

A very good question, and one for which there is no satisfactory answwer.

"In addition, the fact that the draw lines on barrel and receiver do NOT always line up perfectly would show they were not made at the same time."

A comment made by August Weiss (the Director for all handgun production at Mauser, previously a manager at DWM) in his private journal, quoted in G�¶rtz & Bryans, speaks specifically to this point in describing "many thousands" of WWII P-08 which were rebarrelled at the factory after test firing. The large number of other Lugers whose witness marks do not match defy easy explanation, and this disturbs me.

"If the purpose was simply to show the original barrel position, they would have been made with the same tool at the same time, with a single blow. That is obviously NOT the case, as a close look at several Lugers will show."

Some of the Lugers examined patently show witness mark lines which were clearly stamped with a single instrument at one blow, and have just as clearly not been disturbed.

"Is it too much to ask that collectors have some knowledge of the way factories work? Or are we supposed to assume that the Luger was a heavenly gift, made by divine intervention rather than by the common production techniques of the day?"

Part of the problem, and it is a big problem, is that there does not appear to be contemporaneous descriptions or photographs of exactly -how- a Luger was made. The only documentation we have (at least in English!) is the aforementioned Instructions. In this vacuum speculation is rife.

There are several observed circumstances which your theory does not account for. The perfect witness marks are one; there are also guns whose barrels have no witness marks at all--much of Krieghoff's production, at least one Police rework, the aforementioned replacement barrels, and for comparison some Mauser Interarms production and modern stainless steel guns.

In the light of these examples, and the documentation which we do have, Occam's Razor doesn't cut your conclusions much slack.

--Dwight

[saxman]

"I wonder why anyone would put 'witness marks' on the barrel and receiver if they were already installed and lined up. What purpose would they then serve?"
Simple, actually. As I explained, after the barrel was properly torqued and headspaced, the witness mark would have been made so the barrel could be removed and the sight and extractor cuts could be made in the correct positions. At reassembly, all the worker had to do was match the witness marks. I believe Jim's description of the various jigs and gauges is correct, but it seems to me that they would have been used at different points in the assembly. For example, the jig which holds the gun and makes the witness mark I think would have been used after initial assembly but before the sight and extractor cuts were made. There had to be such a jig to insure that the cuts would be made exactly 180 degrees from the mark. The weak point in Jim's argument is that the witness mark was put on the barrel before the barrel was threaded to the receiver. Even the use of the threaded gauge does not guarantee that the marks will line up when the proper torque is applied. I just can't see this being the correct sequence; it's imprecise and very 'un-German'!

[Heinz]

According to Gortz and Bryans, German Small Arms Markings. as earlier noted by Dwight Gruber, king of the witness marks, the witness mark is chisel mark applied after proof firing and sighting in. It would seem to serve to verify barrel alignment in case of barrel removal or a sudden loss in accuracy or whatever. A similar mark is used on muzzle loading rifles to insure alignment after breech removal. That mark is also applied with a chisel after breech instalation.

We should be very careful about theories on how a Luger is assembled in the absence of verified instructions or data.

[Jim Keenan]

We should also be careful about taking as gospel the theories of writers who know nothing about gun production or machine shop work.

Saxman, you are correct in that the assembler needed only to align the draw lines when installing the barrel. But that was done on the first, and only, installation of the barrel. That process, with its critical need for a proper crush fit, was not repeated.

And if each barrel was fitted to a receiver to be marked, how were spare barrels marked (and they are)? Even if each was fully installed, how would the anyone know that a barrel installed on one receiver would be OK in another receiver made at another time in another factory? Sorry, it won't wash.

The barrel shoulder and threads were fully machined, the draw line was marked using the gauge, and the rear of the barrel faced off. Then the sight base was machined and the extractor cut made by aligning on the draw line. The chamber was cut and the barrel was then complete, ready for installation. The proper "draw" insured correct headspace.

The entire process, albeit with another gun, is described, with pictures, in United States Rifles and Machineguns by Colvin and Viall. Every other factory did it the same way.

Jim

[saxman]

Interesting discourse. I'll admit I'm speculating based on my knowledge of how things are made, and I hope my post adequately reflected that. The question appears to be still open as to whether the witness mark/draw lines were made before or after barrel installation. This is a part of why we love Lugers. Can you think of another pistol with this level of interest in the details of manufacturing?

[Dwight Gruber]

</font><blockquote><font size="1" face="Verdana,Tahoma,Arial,Helvetica,Geneva">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Originally posted by saxman:
<strong>The question appears to be still open as to whether the witness mark/draw lines were made before or after barrel installation</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">The question is not open. The Army instructions to the maunfacturers of Lugers as to how they were to proceed in applying witness marks are explicit. Government inspectors observed the work at many stages of manufacture to make sure that Lugers were manufactured as instructed. Original unmounted replacement barrels are observed with no witness mark.

Documentation in English describing the actual steps in Luger manufacture leading up to the final witness mark strike is not forthcoming. Description of the manufacture of other firearms, applied to the Luger by analogy, cannot be promulgated as fact.

--Dwight

[saxman]

Well, that's clear enough for me. Thanks, Dwight, for the detailed analysis.