Basic Disassembly, Repair & Reassembly of a Jack Knife.

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

Postby orvet » Sun Nov 26, 2017 10:43 pm

The first thing that comes to mind is that it is an unnecessary expense.
The second thing that comes to mind is you will see a great increase in the number of cracked handles because if the tapered pin perfectly fits the holes then the first time you put the hammer on the end of the pin to peen the pin you will be exerting outward force the entire length of the handle material.

I make sure I have at about 0.005” clearance between my pin and the wall of the hole through a bone handle. Sometimes even more because when you tap the end of the pin to peen it, it can swell further down the pin. All of the outward pressure is not contained at the top where I want the head to form, but some of that pressure is directed outwards further down the hole and that’s why I always say drill a hole that is larger than the pin stock I am using.
For example for a 1/16” pin I use a #51 drill. The 1/16” pin is 0.0625” and the #51 drill is 0.0670” – this allows 4 ½ thousands clearance. This is adequate for a 1/16” pin but if I were using a 3/32” pin I might leave a little more clearance than 5 thousandths especially if it is a brittle material like bone and most especially if I were peening the head of the pin instead of spinning it.

Those are my initial thoughts on the subject.
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americanedgetech
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Re: Basic Disassembly, Repair & Reassembly of a Jack Knife.

Postby americanedgetech » Sun Nov 26, 2017 11:35 pm

I 100% get your points, and have thought about them before posting the question.

Assume your taper, (in your handle material) and pin match exactly down to the original pin hole in the liner, and your material is a hard stone that can not tolerate pressure. Let's say quartz crystal. Setting (gluing) the stone, and inserting the pin thru the handle into the liner to be silver soldered "could" be the easiest, and dare I, best way to set a brittle material. Maybe?

For softer materials I agree that this would be a lot of effort, and expense (tools, material, time), and why re-invent the wheel?
For brittle materials I see this as a plus but I have more thoughts than experience. That's why I post my thoughts. :lol:
Ken Mc.

WTB Kershaw 2120 MACHO Lockback Parts knife
I need a pile side scale. THX!

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

Postby orvet » Mon Nov 27, 2017 1:31 am

americanedgetech wrote:Assume your taper, (in your handle material) and pin match exactly down to the original pin hole in the liner, and your material is a hard stone that can not tolerate pressure. Let's say quartz crystal. Setting (gluing) the stone, and inserting the pin thru the handle into the liner to be silver soldered "could" be the easiest, and dare I, best way to set a brittle material. Maybe?


I guess my question would be; Why do you want to use a material that cannot tolerate pressure as a knife handle? The first time it gets dropped on a hard surface the pressure created from the shock of the drop will break the handle. ::shrug::
Why would you go to the extra time and effort, (which in manufacturing equals money), to use such a fragile material that the knife could never be an EDC?
A knife like that would be a safe queen only. If you you’re making a safe queen just glue the handles on and don’t worry about pinning them.


If you really believe that method will work the best, then do it, but unless you are going to use this method then this has only been an exercise in mental gymnastics! All the what if this, and what if that questions are fine and dandy if you are going to using those methods, such as tapered pins for handles. But if you’re not going to use those methods it’s a waste of time for everyone.

Cutler’s have been using round pins for hundreds of years and they work perfectly well.
Why beat your head against the wall to reinvent a more costly wheel that may or may not work?
Especially when it will likely be cost prohibitive from a manufacturing standpoint?
It doesn't make sense to me.
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Re: Basic Disassembly, Repair & Reassembly of a Jack Knife.

Postby americanedgetech » Mon Nov 27, 2017 1:51 am

:lol: :lol:
Good points for sure.
It's that stone handle knife that set me thinking about this, and yep, I have the seller with the tapered pins bookmarked.
They are actually for clock repair. He sells a hundred assorted sizes for around 15 bucks on FleaBay

Bill DeShivs said something that stuck with me. (paraphrased) "Learn all the methods, and use the ones you feel comfortable with."
You've noticed yourself that I analyze everything until I throughly understand the process, and the forces at play. Part of my process is looking for improvements where (most often) they are not needed but they still may be an improvement. ::hmm::

I get the safe queen analogy and for sure I'd like to build myself one. After all it will most likely be less fragile than a dropped cell phone, and it'll cost me far less. :lol:
In fact I'll make that a personal challenge for myself. A quartz crystal handled folder. ::super_happy::

I appreciate your patience, and your input Orvet. I know I have a long way to go. ::handshake::
Ken Mc.

WTB Kershaw 2120 MACHO Lockback Parts knife
I need a pile side scale. THX!


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