Basic ISC stockman anatomy 101 / Codger ramble

Codger_64

Codger_64

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I have seen exploded views of knives for quite some time, but none that really matched my favorite folder, the 897UH. LT showed us an acrylic handled knife a while back, and I have seen one or two on ebay meant, I think, to aid assembly workers and as a sample development tool. I worked as a patent illustrator for quite a few years, and as a manufacturing engineer, so I have a pretty good grasp of assembly drawings, methods etc. Also , recently I had run across several references to "keyhole construction" in my research. Vas es das?

Being the curious guy I am, I decided to dismember a 897UH Signature Premium Stockman to find out. Now, I do have several in my collection in addition to my EDC, but I was unable to bring myself to open one up. Luckily, another collector I discussed my angst with opened his morgue box and sent me a cadaver to work with.

Here is the disassembled knife along with my (still assembled) EDC:


There are 15 main components, and seven pins of various types, for a total of 22 parts comprising this knife. This does not count the two tommy on pins on each of the four bolster halves.

The knife is constructed of three main subassemblies. (1) The front handle, consisting of staglon delrin cover with glued UH shield, and pinned with two brass handle rivets to a brass liner, with a bolster half fixed to each end by two molded in pins flared after insertion. (2) the spring/blade stack consisting of the single ended head spring, the main Turkish clip blade bearing the tangstamp, the brass center scale, a double end spring, the sheepfoot blade and spey blade, pinned with a larger bolster pin at each end. NOTE: The double ended spring is not captured in the stack until final assembly. (3) The rear handle, consisting of the cover pinned with two brass handle rivets to the brass liner, and a bolster half fixed to each end

In final assembly, the components are fitted together with the enlarged head of the spring/blade stack pins placed through the large portion of the keyhole in the brass liners, and moved upward to engage the smaller portion of the keyhole slot, locking the heads of the pivot pins into the liners. The assembly is then placed in a jig where the center hole in all the components are alligned, and the brass center pin is driven through and braded on the opposite side.

Of course, this leaves out all the other steps required to assure fit such as crinking the blades so that they pass each other and the liners and nest properly, adjusting the blade kick for blade nesting height so that the blade does not rest with the nick too high or too low, polishing and finishing.

Now you know what keyhole construction is, and I have to figure out how to mount all the pieces in exploded view for a display. Cast acrylic?

Codger
 
A very interesting read, codger. I recieved my 897UH in the mail today (thanks for helping me along the way, and also , thanks to all of those who participated). an exploded veiw for display would be really nice. You got my wheels turnin, maybe I should pick up those $5 broken bladed knives and peice them together for a good eploded view. A nasty sickness I have come down with, no need to find a cure though :D
 
Well done, Codger.

Here is another composite...it's not any better than yours... just a different version.

Bill
 
Yes, that is the Old Timer version with one peg on the inner bolsters, and the pivot pin driven through, not the keyhole construction. Thanks!

Codger

PS- Some of the terms I used are probably wrong, and some probably have more correct names. If you know one is wrong, PLEASE let me know! If I botched the order of assembly, let me know that too.
 
Great stuff, Codger. But, this sort of thing, as Muskrat Man said, only makes our disease more serious. :D

I agree: clear cast acrylic display. Perhaps vertical, or capable of standing up vertical, so the opposite side is also viewable?
 
something like what they put scorpians and rattlesnake heads in to make paper weights. I think that would be a nice addition to any collection. I wonder where a guy could have something like that done?
 
Was ist das?, he he, I think your Spanish is better than you German.

I have taken apart my little OTX folder (It's the 24OTX I think), the fit and finish when new was not that good and even though I did fix it a bit I was never happy with it, I am a curious guy too so I took it apart.

My dad used to do that putting things in acrylic thing, he also made acrylic stuff, like chess sets and such, I remember it's not hard, being a manufacturing engineer you probably know all about it. You buy the stuff, (polymer and accelerant or catalyst or whatever it is called in English), you need a mold which can be made from some kind of silicon that you get from the same supplier or it can be made from clay and varnished on the inside so the acrylic wont stick to it, you can probably buy premade molds or even use a cardboard box or whatever. Mix the resin, fill part way, when solid put in the stuff, mix more resin and fill full, make sure there are no bubbles, let it solidify, take out, clean and polish.

Luis
 
I generally understand Schrade bolster construction, but can you elaborate on how the bolster is actually attached? I see a pair of pin receptacles on either side of the keyhole to keep them from rotating, but what keeps em on?
 
Two offset studs (tommy on pins) are molded into the rear of each bolster. They are inserted into the two holes in the liner, then bradded (spread) to keep the bolsters tight to the liner. they are then ground flush on the inside of the liner so as to not interfere with the pivot pins. The bradded portion of the bolsters in the top of the picture were sanded below flush and then tapped out of the two liner holes to remove them.

That help?

Codger
 
I believe the pins on the sides of the keyhole (Tommy pins) when set in they expand putting pressure in the holes and liners and keep the bolster in place. When the knife is put together the bolsters are naturally held together by the pivot pins with those little wheel like ends inside the keyholes.

Luis

Edited,

You beat me to the answer Codger, I have never separated the bolsters from the liners, I wonder if the tommy pins are actually molded in or pinned into the bolsters.
 
On the 897, they are molded in studs. They might be press fit on other patterns though.

Codger
 
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