Basic Disassembly, Repair & Reassembly of a Jack Knife.

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Jeffinn
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Re: Basic Disassembly, Repair & Reassembly of a Jack Knife.

Post by Jeffinn »

Lansky1 wrote: Thu Dec 24, 2020 12:46 pm Hi knife guru's ... I bought a Case small gunstock with the intention of removing the tiny pen blade. I'm reading all the information here (tremendous resource - thx to all for posting tips / methods). I'm a Case guy and need to order some pin stock. Can anyone please give me a few common pin diameters that I'll need for reassembling common modern Case patterns ? I was hoping to only buy a few sizes to start with & build up my stock if I take to this ... many thanks !!

John (PS - I'm sure glad for AAPK - I was going to try and just punch out the pins with the hopes of re-using them ... seems that's not possible as the pins need to be cut & would have been an expensive learning experience. Just want to confirm though - is it really THAT difficult to punch out the center & 2 bolster pins rather than cutting them to get the knife apart ??)
You might get a better response if you post this in the Knife Repair and Restoration section. I don’t generally work on Case knives so I can’t help you with your question but there’s some folks in the repair group that should be able to help.
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Re: Basic Disassembly, Repair & Reassembly of a Jack Knife.

Post by Reverand »

On some knives I have been able to remove the flared head on one side of a pin, using a ball burr on a Dremel. Then I drive the pin out.
I have not been able to do this on a Case pivot pin get.
That doesn't mean that you won't succeed where I failed, so you should try.
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Re: Basic Disassembly, Repair & Reassembly of a Jack Knife.

Post by orvet »

Lansky1 wrote: Thu Dec 24, 2020 12:46 pm
Can anyone please give me a few common pin diameters that I'll need for reassembling common modern Case patterns ? I was hoping to only buy a few sizes to start with & build up my stock if I take to this ... many thanks !!

Just want to confirm though - is it really THAT difficult to punch out the center & 2 bolster pins rather than cutting them to get the knife apart ??)
The size of the pivot pin depends on the size of the knife, I have worked on Case knives but not enough to memorize the sizes of all the pins they use.


As to your second question: It is possible and even fairly easy IF you have the technique, practice and proper tools.
The pivot pins are tapered and you will need to drill into the pin and remove enough pin material so the sides of the pin can collapse inward when you drive the pin out.
If you drive the pin out without removing enough of the center you can widen the taper so that the new pin won't stay in unless you find the proper size broach to re-taper the pin hole.
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Re: Basic Disassembly, Repair & Reassembly of a Jack Knife.

Post by Lansky1 »

orvet wrote: Sat Jan 02, 2021 3:33 pm
Lansky1 wrote: Thu Dec 24, 2020 12:46 pm
Can anyone please give me a few common pin diameters that I'll need for reassembling common modern Case patterns ? I was hoping to only buy a few sizes to start with & build up my stock if I take to this ... many thanks !!

Just want to confirm though - is it really THAT difficult to punch out the center & 2 bolster pins rather than cutting them to get the knife apart ??)
The size of the pivot pin depends on the size of the knife, I have worked on Case knives but not enough to memorize the sizes of all the pins they use.


As to your second question: It is possible and even fairly easy IF you have the technique, practice and proper tools.
The pivot pins are tapered and you will need to drill into the pin and remove enough pin material so the sides of the pin can collapse inward when you drive the pin out.
If you drive the pin out without removing enough of the center you can widen the taper so that the new pin won't stay in unless you find the proper size broach to re-taper the pin hole.
Thank you Dale - appreciate that advice about hollowing out the pins before punching out. I'm curious about the tapered pivot pins (never knew that) ... do you have to taper the replacement pivot pin rod stock to match the internal taper ? Also, was wondering if there is a rule of thumb on which side normally has the larger end of the tapered pin - pile or shield side (this would determine which side I would want to punch from) ? Thanks again !

John
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Re: Basic Disassembly, Repair & Reassembly of a Jack Knife.

Post by orvet »

The pins are tapered because they are peened in place and are mashed out to assume the shape of the tapered hole.
To put in a new pin you only need a straight piece of the proper size pin stock, (it is untapered).
The mistake many people make is to assume they can I put the straight pin in the hole and just peen down the pin, file or sand off the excess, and they are good to go. In many cases that will work. But if the taper had been messed up on either side, the pin may loosen.
To prevent this you need to reestablish the taper at outside of each hole in the bolsters. It only needs to be a few thousands taper. It requires a broach or a tapered reamer and just need to go deeply the bolster, a few thousands of an inch is preferable.
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Re: Basic Disassembly, Repair & Reassembly of a Jack Knife.

Post by Lansky1 »

orvet wrote: Sat Jan 02, 2021 6:04 pm The pins are tapered because they are peened in place and are mashed out to assume the shape of the tapered hole.
To put in a new pin you only need a straight piece of the proper size pin stock, (it is untapered).
The mistake many people make is to assume they can I put the straight pin in the hole and just peen down the pin, file or sand off the excess, and they are good to go. In many cases that will work. But if the taper had been messed up on either side, the pin may loosen.
To prevent this you need to reestablish the taper at outside of each hole in the bolsters. It only needs to be a few thousands taper. It requires a broach or a tapered reamer and just need to go deeply the bolster, a few thousands of an inch is preferable.
Thanks Dale for taking the time to explain the tapered aspect of the ends of the pins - appreciate it ::tu::
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John
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Re: Basic Disassembly, Repair & Reassembly of a Jack Knife.

Post by orvet »

You're most welcome John. ::tu::

It really is kind of a deceptive term when I stop to think about it. Ever since I started working on knives I've always heard them described as tapered pins. But in most cases the pens are not tapered when they are installed, they are tapered when they are peened to fit into the tapered hole.
Thinking back to when I first started working on knives, I don't think I understood the term the first time I heard it either. Someone had to explain it to me.

There were some larger 1/8" pins Schrade used which were tapered on one side. I think that was to make it a little easier to install the pin. There is a lot more metal to move in a 1/8" and if you only have to peen one side it's much easier and there's less chance of making mistake.
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