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Side to Side Blade Movement on Custom LB when closed

Posted: Sun Mar 17, 2024 3:00 am
by QTCut5
I suspect this Michael Fisher custom bullet end lock back may be one of his earlier builds. It's a cool little knife and I love it but it lacks a certain sophistication in the fit and finish commonly seen in his later work after he had gained more experience.
IMG_E1161.JPG

The one thing that I'm curious about is the side to side blade movement when the blade is closed. It is loose and sloppy, unlike any other custom or factory lock back knife I own. There is also a slight amount of side to side movement when the blade is open and locked as well but not nearly as much.
Is this something that can be fixed/tightened by a knife mechanic? (not by me as I lack the tools and skills for any knife repair more complicated than oiling a pivot joint ::nod::)

To illustrate:

The blade can be manually manipulated both to the right and to the left of center when closed. It can even move on its own when picking up or setting down the knife, which is how I first noticed the slop - I heard the blade tap against the liner when I set it down on a cloth.
centered
centered
off-center left
off-center left
off-center right
off-center right

Re: Side to Side Blade Movement on Custom LB when closed

Posted: Sun Mar 17, 2024 3:21 am
by orvet
The first thought that comes to my mind is it may be a worn pivot pin, or an undersized pivot pin. The knife doesn't look as though it's been used enough to have a worn pivot pin, but that's difficult to tell from the pictures.

Re: Side to Side Blade Movement on Custom LB when closed

Posted: Sun Mar 17, 2024 3:37 am
by QTCut5
orvet wrote: Sun Mar 17, 2024 3:21 am The first thought that comes to my mind is it may be a worn pivot pin, or an undersized pivot pin. The knife doesn't look as though it's been used enough to have a worn pivot pin, but that's difficult to tell from the pictures.
I doubt the pivot pin is worn since I bought it new, but undersized makes sense.

Would I be correct in assuming the pin could be replaced but it would require a complete disassembly of the knife?

Re: Side to Side Blade Movement on Custom LB when closed

Posted: Sun Mar 17, 2024 6:23 am
by orvet
QTCut5 wrote: Sun Mar 17, 2024 3:37 am
I doubt the pivot pin is worn since I bought it new, but undersized makes sense.

Would I be correct in assuming the pin could be replaced but it would require a complete disassembly of the knife?
I thought you may have bought it new and with as many knives as you have I doubt it would have been worn out, but I didn't know for sure until you said so.

As far as replacing the pin, I'm not sure without examining the knife, and even then you usually can't tell if there's a bushing in the knife that may be worn without disassembling the knife. Though, I doubt it worn bushing would give that much play to the blade.
Since it's a Custom Knife you have no way of knowing how the knife maker made it without taking it apart. It would seem to me that it should be fairly straightforward, but working on knives that sometimes like working on cars. You may be 99% sure what the problem is but, sometimes that 1% reaches out and bites you.

If the maker is still in business, I would contact him and see if he could repair it. I always dislike repairing or customizing another makers work.

Re: Side to Side Blade Movement on Custom LB when closed

Posted: Sun Mar 17, 2024 6:40 am
by QTCut5
Thanks for that, Dale. I understand what you mean about working on a custom knife...unfortunately, the maker of this knife (and former AAPK member), Michael Fisher, passed away recently so that option is no longer available.

Anyway, I was mostly just curious about what would cause the blade to have that kind of movement and I think you nailed it: an undersized pivot pin...I suspect an undersized pin was used when the knife was originally made. But, like I said, I believe this knife was one of Fisher's early projects so it was a rookie mistake. I know he got better at his craft because I have a couple more that he customized and they are top notch.

Re: Side to Side Blade Movement on Custom LB when closed

Posted: Sun Mar 17, 2024 12:38 pm
by herbva
Q, I think I can clearly see the pivot pin head when I expand your pictures (dead center in the bolster in your first picture). I'm guessing that it was never peened properly to begin with and needs to be replaced. But, as Dale said, I would would need to see the knife. Lana 'iʻo ka manaʻo!

Re: Side to Side Blade Movement on Custom LB when closed

Posted: Sun Mar 17, 2024 3:23 pm
by ea42
If it's assembled with just a pivot pin, the pin has to be be peened more to bring the liners together and remove the slop. If there's a bushing the same applies, but there's also the possibility that the bushing is too wide, preventing the liners from coming together. If the hole in the blade is a larger diameter than the bushing you won't be able to remove the slop. The blade is flopping around on the too wide bushing. You'd need a new bushing that's thinner and the same diameter as the hole in the blade tang. That's just a single scenario though, might not apply to your knife. I'd try peening the pin (lightly) first to see if that helps.

Eric

Re: Side to Side Blade Movement on Custom LB when closed

Posted: Mon Mar 18, 2024 2:17 pm
by muskrat man
I'm betting Mike would tighten that up for you, I have always heard good things about his CS. It's likely a slightly undersized pin or it just wasnt peened quite tight enough

Re: Side to Side Blade Movement on Custom LB when closed

Posted: Mon Mar 18, 2024 3:22 pm
by QTCut5
QTCut5 wrote: Sun Mar 17, 2024 6:40 am the maker of this knife (and former AAPK member), Michael Fisher, passed away recently so that option is no longer available.

Re: Side to Side Blade Movement on Custom LB when closed

Posted: Tue Mar 19, 2024 8:45 pm
by muskrat man
QTCut5 wrote: Mon Mar 18, 2024 3:22 pm
QTCut5 wrote: Sun Mar 17, 2024 6:40 am the maker of this knife (and former AAPK member), Michael Fisher, passed away recently so that option is no longer available.
Oh, I wasn't aware of that. Sorry to hear it, he was very good at what he did.