I have read with great interest the article pinned by Dietrich, and the 50 (odd) page thread on the 2 dies debate as well. A big big thanks to Dietrich, Dave and the others who participated...(and to Skip for getting us all going) because by their collective participation knowledge of this fascinating topic has moved on significantly.
I'd like to pose a few comments, and invite debate.. Hope you are all up for it
What were S&L doing different from the other RK manufacturers that caused them problems that Juncker & K&Q who were probably as (if not more) prolific didnt experience (?). Original K&Q frames for example are all pretty much the same with little detectable difference between periods of manufacture
The possibility occurs to me that S&L used (1) a different production process causing material problems with the base metal of the dies, or that (2) the base metal was defective or incorreclty chosen for the die
I'd better point out now that I am in the "single die" camp. I am prepared to admit that the hub and working die scenario was possible, but that for some reason S&L and the other RK manufacturers did not use it.
That having been said and taking the two points mentioned above as the working hypothesis, I'd like to postulated that the different production process used by S&L could have been that the female die only had the fine details whereas the upper male part was more of a "plug" to force the silver material into the female. This process would be much more stressfull to the dies (particulary to the female) as considerably more pressure would be required than if both male and female were detailed. Do we have any evidence of this (?)....if we are seeing only flaw ridge features in the frame defects, as indeed we seem to be, then it might indicate this.
If both upper and lower parts of the die were detailed and of exactly the same material then it might reasonably be expected that eventually both parts would exhibit problems (although maybe the female much earlier) causing both ridges for female defects and flattening of beads for male flaws on the very heavily flawed "B" type.. Is there any evidence of this (?)...I'm unsure. But then maybe the stresses involved never reached critical levels for the male.
From a practical point of view, such a die arrangement would be much easier to make than one with detail on both sides that must exactly mesh, and I'm sure S&L were very economical (!)
OK...thats the different process scenario. It doesnt matter too much but could explain why S&L had die problems where the others did not, or certainly not to the same extent.
..now moving on to the defective material scenario as a theory for S&L's problems, which might or might not be linked to the production method;
If the base metal was defective in some way (by its inherent characteristics or of an unsuitable grade for the physical design of the die) the die might suffer excessive material fatique effects caused by the natural tendency of the female to flex when the frame was pressed. This could result in fatique defects appearing at the points of extreme cyclic stress, which would naturally be at the low points of the female die. This is in fact where we see most of the flaws
Such fatique failures would appear commonly as either cracks (splits) or by a loss of base material. If the former, then I would expect to see a proliferation of cracks that increased in length over time. Stresses are naturally concentrated at the extremeties of cracks...and there is a natural tendency for them to grow.
But the flaws we are seeing do not appear to grow substantially...they are either there or they are not.
Also, In the "crack" scenario there would be a tendency for the crack to close once pressure was released. (This would also tend to pinch any material squeezed into the flaw incidently). In this case the traditional repair would be to "block" the die, thereby reducing/illiminating flexing. But then if flexing was cured by this method, why did further flaws appear post 935/4 if the die couldn't flex (?) It just doesn't add up.
I favour the theory that base material began to be lost at the bottom of the female die due to fatique related problems. This would allow the flaws to be exposed even when the die was not under pressure, and repair to be effected by filling of the cavities, which to me is clearly what hapened....voila, the 800/4 frame !...from this point onwards further material failure/loss could logically still be expected, and 935 silver was tried to reduce the stress on the die...voila the 935/4. We might actually see signs of small repairs between 800/4 and 935/4 (I think we have only looked so far at 800 to 935/4 repair spider web pattern on the beads so far).
In light of the evidence we have, its not unreasonable to assume that the 935/4 were the last official 1939 S&L RK, and that anything with the post repair features that isnt a 935/4 and shows further deterioation is post war (maybe even post 1957).
It might well have been that post 935/4 regular runing repairs were required and that eventually they were such a "pain" that S&L made a new 1957 die and dumped the original. Alternatively, (maybe stretching a point) S&L didnt want to be associated with the post war "under the counter" production of 1939 RK's as it dawned on them that they were exposing themselves to that acusation if they continued to use the original pattern frames on the official 1957 cross (and thereby confirming that they had been the source of the post 1939 swastika versions).
Comments invited.
Regards
Chris
I'd like to pose a few comments, and invite debate.. Hope you are all up for it
What were S&L doing different from the other RK manufacturers that caused them problems that Juncker & K&Q who were probably as (if not more) prolific didnt experience (?). Original K&Q frames for example are all pretty much the same with little detectable difference between periods of manufacture
The possibility occurs to me that S&L used (1) a different production process causing material problems with the base metal of the dies, or that (2) the base metal was defective or incorreclty chosen for the die
I'd better point out now that I am in the "single die" camp. I am prepared to admit that the hub and working die scenario was possible, but that for some reason S&L and the other RK manufacturers did not use it.
That having been said and taking the two points mentioned above as the working hypothesis, I'd like to postulated that the different production process used by S&L could have been that the female die only had the fine details whereas the upper male part was more of a "plug" to force the silver material into the female. This process would be much more stressfull to the dies (particulary to the female) as considerably more pressure would be required than if both male and female were detailed. Do we have any evidence of this (?)....if we are seeing only flaw ridge features in the frame defects, as indeed we seem to be, then it might indicate this.
If both upper and lower parts of the die were detailed and of exactly the same material then it might reasonably be expected that eventually both parts would exhibit problems (although maybe the female much earlier) causing both ridges for female defects and flattening of beads for male flaws on the very heavily flawed "B" type.. Is there any evidence of this (?)...I'm unsure. But then maybe the stresses involved never reached critical levels for the male.
From a practical point of view, such a die arrangement would be much easier to make than one with detail on both sides that must exactly mesh, and I'm sure S&L were very economical (!)
OK...thats the different process scenario. It doesnt matter too much but could explain why S&L had die problems where the others did not, or certainly not to the same extent.
..now moving on to the defective material scenario as a theory for S&L's problems, which might or might not be linked to the production method;
If the base metal was defective in some way (by its inherent characteristics or of an unsuitable grade for the physical design of the die) the die might suffer excessive material fatique effects caused by the natural tendency of the female to flex when the frame was pressed. This could result in fatique defects appearing at the points of extreme cyclic stress, which would naturally be at the low points of the female die. This is in fact where we see most of the flaws
Such fatique failures would appear commonly as either cracks (splits) or by a loss of base material. If the former, then I would expect to see a proliferation of cracks that increased in length over time. Stresses are naturally concentrated at the extremeties of cracks...and there is a natural tendency for them to grow.
But the flaws we are seeing do not appear to grow substantially...they are either there or they are not.
Also, In the "crack" scenario there would be a tendency for the crack to close once pressure was released. (This would also tend to pinch any material squeezed into the flaw incidently). In this case the traditional repair would be to "block" the die, thereby reducing/illiminating flexing. But then if flexing was cured by this method, why did further flaws appear post 935/4 if the die couldn't flex (?) It just doesn't add up.
I favour the theory that base material began to be lost at the bottom of the female die due to fatique related problems. This would allow the flaws to be exposed even when the die was not under pressure, and repair to be effected by filling of the cavities, which to me is clearly what hapened....voila, the 800/4 frame !...from this point onwards further material failure/loss could logically still be expected, and 935 silver was tried to reduce the stress on the die...voila the 935/4. We might actually see signs of small repairs between 800/4 and 935/4 (I think we have only looked so far at 800 to 935/4 repair spider web pattern on the beads so far).
In light of the evidence we have, its not unreasonable to assume that the 935/4 were the last official 1939 S&L RK, and that anything with the post repair features that isnt a 935/4 and shows further deterioation is post war (maybe even post 1957).
It might well have been that post 935/4 regular runing repairs were required and that eventually they were such a "pain" that S&L made a new 1957 die and dumped the original. Alternatively, (maybe stretching a point) S&L didnt want to be associated with the post war "under the counter" production of 1939 RK's as it dawned on them that they were exposing themselves to that acusation if they continued to use the original pattern frames on the official 1957 cross (and thereby confirming that they had been the source of the post 1939 swastika versions).
Comments invited.
Regards
Chris
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