Case Delrin?

[TAH]

I'm considering purchasing a Case jigged Delrin handle knife. I am looking at knives from the 70s/early 80s. During my search, mostly on eBay and AAPK, I've noticed several used and unused knives that have a crack in the handle at the pin. Thinking that Delrin would be fairly tough, I am a little surprised by this. Why so many cracks?

 

[WinchesteRalox]

I’d imagine it would be because the pin causes a stress point. hear that it happens with bone quite frequently.

 

[Bartleby]

I’d imagine it would be because the pin causes a stress point. hear that it happens with bone quite frequently.

Correct in both cases. The great thing about delrin compared to natural materials is that the pin crack will seldom if ever spread. The cracked ones make great users at lower cost than pristine examples.

 

[afishhunter]

I’d imagine it would be because the pin causes a stress point. hear that it happens with bone quite frequently.

Why don't the Old Timers with Delrin covers have cracks?
Did Case use a different grade or formulation of Delrin than Schrade?

I agree about the bone and stress cracks, but from what little I've seen, the pin cracks in bone are created when the knife is made, not after up to a century plus of use.

 

[afultz075]

My Yellow CV Case Sodbuster I bought new about 5 years ago and has lived unused in a knife roll that whole time and has recently developed a crack at the center pin just from me opening and closing it about a dozen times over the years.

 

[JB in SC]

Cracks in older delrin Case knives is not uncommon, I've seen it pretty often on slimline trapper 048 patterns.

Very common with some patterns of the reintroduced Remington series made by Camillus as well.

 

[supratentorial]

Why don't the Old Timers with Delrin covers have cracks?
Did Case use a different grade or formulation of Delrin than Schrade?

I agree about the bone and stress cracks, but from what little I've seen, the pin cracks in bone are created when the knife is made, not after up to a century plus of use.

Both are not rare. I've had bone handled knives from Queen and GEC develop cracks after far fewer than 100 years. Below is a photo of a pin crack on a Schrade. This knife is new and never used so the pin may have been over tightened at the factory. I think there are some differences in the delrin used by Case on the oldies and the current stuff. I don't think it's just the aging of the material but also the properties in the material itself. I have not yet had a modern yellow delrin Case knife develop a crack. Could happen but it's never happened to me and I've dropped my users a few times. Bone would have cracked for sure from the same drops. Delrin is pretty durable stuff.

 

[afishhunter]

Both are not rare. I've had bone handled knives from Queen and GEC develop cracks after far fewer than 100 years. Below is a photo of a pin crack on a Schrade. This knife is new and never used so the pin may have been over tightened at the factory. I think there are some differences in the delrin used by Case on the oldies and the current stuff. I don't think it's just the aging of the material but also the properties in the material itself. I have not yet had a modern yellow delrin Case knife develop a crack. Could happen but it's never happened to me and I've dropped my users a few times. Bone would have cracked for sure from the same drops. Delrin is pretty durable stuff.

Oh, I agree! Delrin is incredibly tough and durable.
I'm thinking maybe G10 could beat it, but I don't know for sure, and I'm quite positive that I will be long gone before the long term durability of G10 as a knife handle material can be determined.
Delrin has been used for what? 80? 90? years or more? to earn it's reputation for toughness and durability?

 

[Woodrow F Call]

Why don't the Old Timers with Delrin covers have cracks?
Did Case use a different grade or formulation of Delrin than Schrade?

I agree about the bone and stress cracks, but from what little I've seen, the pin cracks in bone are created when the knife is made, not after up to a century plus of use.

afishhunter I have a 34OT with a crack in it. My Case knives don't though.

 

[TAH]

Thanks everyone! I appreciate your feedback and expertise.

 

[Dfunk1210]

I am a newbie at Case knives. Is Delrin the same as the standard yellow synthetic? Ive seen both listed and never understood the difference.

 

[leghog]

Why don't the Old Timers with Delrin covers have cracks?
Did Case use a different grade or formulation of Delrin than Schrade?

I agree about the bone and stress cracks, but from what little I've seen, the pin cracks in bone are created when the knife is made, not after up to a century plus of use.

They do. I had one with that crack.

 

[jakemex]

Yellow delrin does crack at the pins. Funny thing though...
The knives still cut and are great users. My 42 year old slimline trapper still a great knife cracks and all.

 

[Obsessed with Edges]

True 'Delrin', by Dupont, was originally invented as named in the 1950s. Case first started using it in 1967, with the first Sod Buster (2138 pattern). The 'synthetic' or 'composition' covers used by Case prior to that were of something different, and I've no idea what they used, prior to Delrin. A while back, I'd done some web searching on 'Delrin', and found that over the years/decades, Dupont has developed maybe dozens of different formulations of 'Delrin', each tailored to be useful in different applications (on their site even today, they list at least 85 formulations currently available). Some are made for greater toughness, others perhaps for strength, others for dimensional stability (resistance to shrinking), lubricity (for washers/bushings/etc), resistance to chemicals, heat, etc. So, it'd be hard to pin down exactly what type(s) Case might've used over the years, or if they even used similar materials from different mfrs, etc.

Pin cracks can happen if the cover materials are too thin, or if they're drilled too close to an edge, or whatever. So it's possible that manufacturing methods/practices might create issues from one maker that might not be seen in the same material from other makers. I could even see, if the Delrin covers are otherwise firmly attached to the scales themselves, near the ends, the anchor pinhole itself could be drilled to allow some movement of the spring's anchor pin, without stressing the Delrin cover and cracking it. So, as I see it, there are many ways to create an issue with cracking, and many ways to avoid it. May not depend as much on the material itself.