How to tell Derlrin from Jigged bone?

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jec88

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I picked up a 10 dot, 1970 Case jackknife (62087). From what I understand, it could be either jigged delrin or jigged bone? Is there any way to tell for sure what it is? It is a CV and has an oval shield if that helps?
Thanks in advance
 
jec88 said:
I picked up a 10 dot, 1970 Case jackknife (62087). From what I understand, it could be either jigged delrin or jigged bone? Is there any way to tell for sure what it is? It is a CV and has an oval shield if that helps?
Thanks in advance
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I think the Case shields were slightly different, bone vs. Delrin. I believe the name CASE on the Bone knives were encircled (closed name). The Delrin were plain with no circle around the CASE name.
 
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This is probably not what you want to do with that knife, but generally, the "acid" test is to heat up a pin and stick it in the scale. Delrin melts, bone burns.

I find also that you can kind of "scrape" the material with your thumbnail. Delrin "gives" a little bit and bone will not; and bone may scuff a little bit, which can be "repaired" by rubbing with mineral oil.
 
jec88 said:
I picked up a 10 dot, 1970 Case jackknife (62087). From what I understand, it could be either jigged delrin or jigged bone? Is there any way to tell for sure what it is? It is a CV and has an oval shield if that helps?
Thanks in advance
Click to expand...

If you could post a pic, I could tell you right away. The 62087 was changed from bone to delrin in 1970, so both handles will be found on 10 dot 1970 examples of the pattern. The shield change was done in 1974 so that won't apply to this knife.

Delrin will have a dull brown/gray color and a slightly greasy feel as compared to bone. If it has any red then its bone.
 
digitalurbancamo said:
The first number in the serial number represents the handle material. The 6 represents bone.
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The '6' represents bone AND any other jigged handle material (jigged bone, jigged synthetic or jigged laminated wood).

( quoted from Case's site -->: http://www.wrcase.com/case_college/handles/handlematerials.php )

"6 - Bone
Procured from Brazil, the shin bone of the Zebu cattle are the main source of bone suitable for Case bone handle materials.

Jigged Synthetic
Plastic molded covers with a jigged pattern.

Jigged Laminate
Laminated wood with a jigged pattern; such as used on the Folding Hunter. "
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Easiest way to tell if it's bone or synthetic, is to look at the material with a magnifier (~10x or so) and very bright light. Bone will always show grain (at depth) and pores; look at edges or ends of scales, or along inside edges of jigging, especially. Synthetic materials may feature simulated grain on the surface, but will not show deep grain, or pores at all.

The jigged laminated wood scales have grain, obviously, but the even layers of the laminate will give that away (like plywood), when looking at edges of covers, under brightly-lit magnification.

The coloring of bone will almost always be somewhat uneven/irregular/blotchy, due to bone's tendency to unevenly absorb dyes, whereas synthetics will show virtually no variation across the material. Case's brown Delrin, in particular, has sort of an odd cocoa tint that becomes more easy to recognize with some experience, as compared to the brown or red bone they've used (either of which may look either chestnut brown or red, or both). Polished bone will show some glassy/watery depth, as well, which is very attractive.


David
 
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