Case Delrin/synthetic cracks

JB in SC said:
Obsessed with Edges Obsessed with Edges

The older ones have a different blade profile, much nicer in my opinion. Plus the handles are more rounded…not so blocky.
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I do have a 'ten-dot' 1970-vintage 2138 Sod Buster, and have noticed differences in the blade profile, including thicker blade stock & spring, and a longer cutting edge / shorter ricasso. It's a heavier knife than the current version most of us are used to seeing. It's the one at left in the 1st pic below. 2nd pic shows the difference in stock thickness and 3rd pic shows differences in the grind, including what appears to be a very subtle convex to the primary grind overall - probably incidental, likely ground on a somewhat slack belt. The other one pictured at right in 1st pic is the 2009 model (2138 SS). I need to dig out the 1970 and look it over again, for other differences. I don't recall seeing any cracks in the covers on that one.
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If I recall correctly in the 1961 to 2004 period Schrade guaranteed their Delrin and Staglon not to crack or chip. It was a major point in their advertisements.

Is it possible that Case and possibly others use a "Delrin" (From what I understand, "Delrin" is a registered DuPont trademark, and the formula is/was patented ... no doubt the patent(s) from the late 1950's when Delrin was invented have long since expired.) from a different manufacturer using a slightly different recipe, meaning the covers/handle is not "real" "Delrin"?
Does Case call it "Delrin" or "Synthetic"? If the latter, it may not be DuPont Delrin?

Not necessarily relevant to the topic:
I've checked all my knives with Delrin covers, the only Case being a black Sod Buster Junior. The others are Schrade Old Timers, Western, and KaBar stockmans, from the 1960's to 1980. None have a crack.
I don't remember the Sod Buster Jr.'s age. Presently all my knives except the ones on me or clipped to a rollator are packed away in boxes. They "need" to fumigate the facility next week. We even have to put all our clothing into plastic bags, for empty closets and empty open dresser drawers. 😡
 
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I have a few delrin/synthetic knives and my sodbuster jr (2018-ish stamp if I recall) is the only one with a crack, and it's in the same spot on the one pin as the others posted.
 
afishhunter said:
If I recall correctly in the 1961 to 2004 period Schrade guaranteed their Delrin and Staglon not to crack. It was a major point in their advertisements.

Is it possible that Case and possibly others use a "Delrin" (From what I understand, "Delrin" is a registered DuPont trademark, and the formula is/was patented ... no doubt the patent(s) from the late 1950's when Delrin was invented have long since expired.) from a different manufacturer using a slightly different recipe, meaning the covers/handle is not "real" "Delrin"?
Does Case call it "Delrin" or "Synthetic"? If the latter, it may not be DuPont Delrin?

Not necessarily relevant to the topic:
I've checked all my knives with Delrin covers, the only Case being a black Sod Buster Junior. The others are Schrade Old Timers, Western, and KaBar stockmans, from the 1960's to 1980. None have a crack.
I don't remember the Sod Buster Jr.'s age. Presently all my knives except the ones on me or clipped to a rollator are packed away in boxes. They "need" to fumigate the facility next week. We even have to put all our clothing into plastic bags, for empty closets and empty open dresser drawers. 😡
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I have no doubt Case has likely used different formulations of what we generically call 'delrin', over the span of decades. Case's first as named use of 'Delrin' was in the original 2138 Sod Buster at its debut in 1967.

Even DuPont has many, many specially tweaked versions of their own true 'Delrin', each formulated to enhance specific traits for specific industry applications, like strength, flexibility, hardness, toughness, lubricity, heat resistance, abrasion resistance, chemical resistance, dimensional stability, etc. So I wouldn't be surprised at all if Case has already gone through many of them over the years looking for something ideal or more economical. I think most of what we casually call 'delrin' in their knives is usually what Case would call 'synthetic' or 'composite'.
 
I have a soddie jr. with the crack, but I also have a yellow handled slimline trapper and mini trapper with the same crack, so I'm not sure it's exclusive to sodbusters.
 
There's a good chance that 95% of the world's population (ok, 50%) knows about the crack emanating from the center pin of the Case Sod Buster Jr. covered with delrin/composite covers yet, Case continues to make them and sell them as fast as they can and we continue to buy them. I think Case must be thinking; "don't fix it if it's not broke", even if it is.
 
Modoc ED said:
I've got a few Case Sod Buster and Case Sod Buster Jr. knives
View attachment 1680877
and after just now checking all of them, only the two small yellow Sod Buster Jr. knives have the subject crack. They've both been like that since I've had them and I've known that the crack is quite common on these knives. When in rotation, I use them quite a bit with no failure in either one.
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Love that Halloween soddie, Modoc ED Modoc ED
 
Yeah this happens sometimes, and on other models too. I had a yellow trapper develop a crack too but it doesn’t hurt anything.
 
I think that stiff spring on the sodbusters in particular helps lead those to crack there. I could be wrong, but I think the shock of the blade snapping open and closed is what is doing it. Having the pin so close and the thinner handle material there doesn't help either...

Open stock delrin Schrades and some similar Imperial patterns have handle material cracks at that pin as well.
 
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