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Tighten an old slip joint

Discussion in 'Non-Firearm Weapons' started by EHCRain10, Jul 30, 2008.

  1. EHCRain10

    EHCRain10 Well-Known Member

    I found an old slip joint while going through my grandfathers things and would like to clean it up to carry on special occasions.
    The blades are pretty sharp now that Ive spent some time with them but one of the blades is not very tight. The smaller of the two blades is tight and has proper tension to hold it in place when opened but the larger of the blades has over a quarter inch of play front to rear, it doesnt go beyond where it should stop but it doesnt stay where it should. Side to side is tight on both blades.
    The handles are old stag with the side closer to the tight blade lining up with the knife body very well but the end opposite of the joint on the side containing the lose blade is shifted towards the rear of the knife.
    I have pics but im not sure how to post them to show details
    Thanks for all the help.
  2. EHCRain10

    EHCRain10 Well-Known Member

  3. Valkman

    Valkman Well-Known Member

    I doubt if it's fixable as the back of the blade is ground to fit tight against the end of the spring. The blade would probably have to be replaced. You really have 2 choices - send it back to who made it or keep it the way it is. I'd leave it as is.
  4. What exactly *is* a '"slipjoint"? Sorry for the mini-hijack - ignore me if you like. I am ignorant of these things.
  5. Mongrel

    Mongrel Well-Known Member

    Traditionally a "slipjoint" is a pocket knife or folder with no locking mechanism on the blades.

    There are also "friction folders" which are an open back folding knife with a tang that is integral to the blade and is rotated 'into' the back of the handle to expose and deploy the blade.

    The difference is that a "slipjoint" will have a spring that keeps tension on the blade and helps to "snap" it in place when opening and closing it. Friction folders do not employ a spring or anything like it, and simply rely on the friction (or tension) at the joint where the blade meets the handle.

    A penknife or pocket knife is said to have good "walk and talk" when the blades are tight, fit well, and "snap" open\closed with authority.

    Hope this helps....

    (feel free to correct where necessary gentlemen...)
  6. Valkman

    Valkman Well-Known Member

    A Case knife with no lock, like a Seahorse, 048 Trapper, etc are slipjoints. The "spring" is steel like the blades but tempered back to "blue" for "springyness" or it'd break under usage.

    These are Case "slippies" that I've rehandled. This is a 048 Slimline Trapper that came with yellow handles and brass bolsters. I tore it apart and gave it titanium bolsters and snakewood handles:


    It does not "walk and talk" like it did before I screwed with it. I need more practice at putting them together.

    Here's a Seahorse that I rehandled in Ironwood:


    You don't want to leave the blades of a slipjoint halfway out like in the pic for long - I display them fully open or closed. In both pics you can see the spring sticking out and under stress.
  7. EHCRain10

    EHCRain10 Well-Known Member

    i looked at the joint end of the loose blade and it looks the same as the same end of the tight blade. Could something be wrong with the spring?
  8. Valkman

    Valkman Well-Known Member

    I don't know - does each blade have it's own spring? Does it "tighten up" with tension as you open it? If the spring is broken then you are not going to be able to fix it.
  9. sm

    sm member


    There are some folks that do restore pocket knives (slip-joints).
    I would post the brand name, and if you have the pattern number that will assist you as well.
    A picture if you could would be nice.

    Different mfgs used different methods in assembly of knives and how the blade pivots.
    Some are more easy to take apart, and repair because of how "crafted".
    Others were designed for ease of mfg and not "really" intended to taken back apart and fixed if needed down the road.
    These can be , it takes someone that knows these.

    Sentimental value is respected by the quality restorers.
    They will have references, and will communicate with you before, during and after the service.

  10. JTW Jr.

    JTW Jr. Well-Known Member

    if you have trouble posting the picts , email them to me and I will host them off my webspace. See if we can help you get your grandfathers treasure back in action :)
  11. gb6491

    gb6491 Well-Known Member

    It sounds like the spring for that blade has gone bad or, less likely, one of the pins holding it (or the blade) has failed.

    If you want to try to repair something like this yourself, I suggest you get a copy of "The Complete Book of Pocketknife Repair: A Cutler's Manual" by Ben Kelly Jr. Other references would/could include obtaining a cheap swap meet style knife or getting a slip joint kit from knifekits.com to practice disassembly/assembly (the most delicate part of the whole operation could be removing the stag scales). Chris Crawford has an excellent tutorial on his site that might be of help: "How to Make a Slip Joint Pocketknife". Give Alvin's site a look as well. If the spring is bad you might be able to re-harden and temper it or you may have to make a new one. A bad pin would require replacement.

    If you don't want to attempt it yourself, I suggest you contact bladefourms.com member STR. He has done similar projects in the past. His subforum there is STR's Backyard Knifeworks Registration is required there to view certain forums.
    Another possibility would be to contact Dirk Potgeiter "aka" Oupa on several knife boards; Backyard Mechanics Forum, Anything Goes
    or Oupa's Knife Workshop.

    You'll get help on any of those forums as well.


    I see you got some excellent advice as I was putting this together.
  12. Alvin in AZ

    Alvin in AZ Well-Known Member

    Hi Greg :)

    Prem, here's a slip joint...
    That's opposite sides of the same pen knife where I cut it in half to work on
    it again. Are scanners cool for showing stuff like that or what? :)

    That's a brand-new "34 Old Timer" I took apart that shows the original spring's
    shape before the blade presses it down.

    I saw the factory's way of putting together slip-joints in Blackie Collin's book
    where he goes through the old Imperial factory, they put in the center pin last
    and after that so do I. :) YMMV

    Alvin in AZ
  13. ArfinGreebly

    ArfinGreebly Moderator Emeritus

    Ironwood Seahorse

    Dammit, Don.

    Yer teasin' me again.

    You 'n' me gonna hafta have a chat about whittlers in Wharcliffe one o' these days.
  14. p35

    p35 Well-Known Member

    I have a thing for old Camillus hawkbills- odd, I know. Try one and you'll never go back to a Spyderco.


    I've tightened several by setting the pivot end flat (ie scales horizontal) on an anvil and whacking the other end of the pivot- gently but as many times as it takes to do the job- with a ball peen hammer.

    Whether this will work on your knife I can't say. You need a metal bolster with the ends of the pivot at least visible. Normally they're polished flat to the bolster so you have to look pretty hard.

    Just one idea, I could be wrong ( I thought I was wrong once but I was mistaken!)

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