K date Luger Hardness

[Thor]

I have reworked about half a dozen of these cool Lugers. The thing that STRIKES me about his is HOW DARN HARD the steel is. This one is REALLY HARD! Any ideas why they would be harder that Erfurts, DWMS and later Mausers????? Especially the receiver on this one! K date FM

[Navy]

Ted,
FWIW, my main gunsmith, who has worked on 'Brooms and Lugers for me, sez that the period 1930-1942 produced the hardest steel he has ever encountered. Always managed to break a couple of tools doing the job.
Tom A.

[Edward Tinker]

Would this equate to more brittle than other years, or just harder?

[ToggleTop]

Thor,
I would be interested in hearing an explanation of what you are experiencing by someone knowledgeable in metallurgy. I am sure they will have an explantion for it. It may be that the process of heat treating metals had advanced much further than when the earlier guns were made. I think I have read something on this, I will see if I can find it.

Regards,

[ToggleTop]

Hello Thor,
This won't answer your question but it may help. The image is a paragraph from an aricle written in the 30th Edition, 1976 Gun Digest by Robert A. Burmeister. It is quite interesting in that he feels the Mauser military lugers (reproductions) were much superior to the earlier lugers in regards to their metallurgy. This may be why you are experiencing what you have noticed in the K-Date. I thought you would be interested.
<img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" />

Regards,

[RockinWR]

Thor/CV,
* Randall Gibson, in Krieghoff Parabellum-Pgs.27 & 28 examines the frame hardness of various Luger Mfgs. in an attempt to see if the origin of the frames could be determined by the relative degree of hardness. Using a Wilson Rockwell hardness tester, against a B scale standard, he recorded values for a 1917 Erfurt (B-21), 1917 DWM(B-22), 1918 Spandau(B-21), 1924 Bern(B-10), a Vickers(B-22), 1925 Simson(B-33), "S" code Simson(B-33), 1937 Mauser Banner(B-31), byf'42-KU(B-31), 1937 Krieghoff(B-32), & 1945 Krieghoff(B-31). Conclusion, the frame Mfg. could not be determined solely by the hardness value.
* A correlary from this data is Simson & WWII mfgd. frames were harder than Swiss & WWI Mfgd. frames.
* Conventional wisdom holds the development in ore refinement, better alloying, improved equipment, and tighter heat treating process control all became markedly improved as the 20th Century progressed. This wisdom nicely summarized by the Burmeister quote above.
* Mauser M98k rifle actions are extolled for their soft core to absorb cartridge impulse shock while hardened on the exterior(skin) to withstand rough mechanical handling treatment. Those who have drilled/tapped for a scope mount can attest to the 98k surface hardness.
* Does the "K" you picture exhibit a higher than "normal" number of hardness test indents(dimples)? Might be S/N 1661 was on the upper side of the hardness tolerance range.
WR

[Barry Briscoe]

RockinWR,
Are you sure that the values that you listed are B scale values? Rockwell B scale values of 10 to 33 would be relatively soft steel.

Rockwell C 10-30 is more likely.The hardness of rifle barrels are usually Rockwell C 25-32 which is easy to machine.
Barry

[RockinWR]

Barry,
* I agree: what you state certainly makes sense.
* I can confirm what is written: Mr. Gibson's Pg. 28 explicitly states "B" scale & the leading "B-xx" of the numerous values recorded make a typo unlikely. Also, note, these are frame values. Maybe only Randall can indicate whether something slipped past the proof readers here.
* Reading further, Pg.33-same Ref. states: While Krieghoff frames average 32 on the B scale, the corresponding receivers averaged a substantially harder 47. The receivers of the other manufacturers tested were correspondingly harder than their respective frames. This hardness difference.....not surprising.....receivers being much more highly stressed during firing than the frames.
* 47 Rb still comes no where close to the 25 Rc (about 100 Rb) which seems to make more sense.
* If any analog to the Mauser M98k receiver can offer insight, Jerry Kuhnhausen, Pg 70-71 of his book Mauser Bolt Actions & Frank de Hass, Pg. 38-39 in Bolt Action Rifles both make good reading on receiver hardness/composition. Essentially, 25-26 Rc case hardness over a 18-20 Rc core. Similar to U.S.'s 1035/1036 steels. However, again, higher 8x57 rifle pressures(48-52k??) vs 30-32k psi for the 9mm.
* Relative to Thor's original observation, this S/N 1161 "K" is fairly early in the start up cycle. I certainly have no documentation of what transpired. However, like a number of manufacturing acceleration programs, I'd hypothesize Mauser's zeal to ramp up on their newly awarded P.08 Military contract got a frenzy going with a number of new trainee's @ Oberndorf. Easy to believe a batch of parts got left in the carburizing box a tad bit long. Of course "Fritz" could have just taken a long lunch. Anyway...no facts; but, the P.08's Mfg. uniformity/consistency seems to have stabilized after 1935 out through 1942.
WR

[trigger643]

Related and not entirely off topic was the metallurgical evolution of the Springfield 1903 receivers at Rock Island and Springfield arsenals. Until roughly the mid 19-teens heat treating was an art. A skilled artisan judged the progress of the process by eye and evaluated the tempering by the color the metal glowed during the process. It wasn't until about 1918 that technology replaced the individual's judgement with standardized and accurate equipment for measurement(at these facilities). The U.S. Military in the 1920's subsequently condemned the rifles made earlier due to a series of catastrophic failures. Many Springfield 03 collectors and shooters are familiar with the legend of it being unsafe to shoot a low digit serial number rifle, and Brophy address this topic in his excellent book on Springfield 1903 rifles. One would think the same evolution occurred in Germany, if not at the same time, shortly thereafter.

[Barry Briscoe]

Here are a couple of tables that might be of interest concerning Rockwell C hardness of steel alloys and file testing for hardness approximation.






I had trouble finding out how to upload a full size photo the other night,easy once I found the link.Thanks!

[Hugh]

I don't know about the frames, but I know that the rear toggles are harder than a w****'s heart, especially the Mauser ones. I cut a dovetail in a DWM rear toggle with a carbide cutter without any problem. A couple of days ago I ruined a HSS and two carbide cutters trying to cut one in a 1937 S/42 rear toggle. It appeared that the DWM toggle had a hard "skin" and was softer inside, the S/42 was HARD all the way through.
<img border="0" alt="[crying]" title="" src="graemlins/crying.gif" /> <img border="0" alt="[grrrrrrr]" title="" src="graemlins/cussing.gif" />

[Dwight Gruber]

As I mentioned a while back in an unrelated topic, and seems worthwhile to reiterate here, many engravers refuse to work on Lugers because of the hardness of the steel.

--Dwight

[John Sabato]

Barry Briscoe,

Your tables need to be at least 2X larger in order to be able to read them. Can you repost larger versions of these tables?