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- Jan 27, 2007
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(For one solution to gaps between liners and backprings, see post #10.)
Tightening joints on slipjoints:
I've seen the question of tightening loose joints on slipjoints – and occasionally lockbacks – come up a few times over the last few years, so I thought I'd put this up. This is lessons I've learned over the years with a lot of the older knives we get here from thrift stores and antique shops. A lot of them are loose, and/or have other issues. Often, all these knives need is simply a little TLC to be "brought back from the dead". (I usually won't mess with fragile or sentimental pieces.) This is in reference to more traditional knives, but it is more in line with this forum, I think.
A few things to remember:
1: Clean out the knife, and oil the joint before any tweaking. Any debris in the joint will just get pressed into the liners, etc. and make things much rougher than before.
2: If you make a knife too tight, you can slip the blade spine of another (identical) knife into the slot at the joint, and gently rock the blade a little. This will loosen it up enough to pivot easily, but hopefully leave it tighter than before.
3: If step 2 is not an option, I use a micrometer on the blade spine at the pivot, and set my feeler gauges to take up the same amount of space when I set up the padded vice. This usually works, but not always.
4: Celluloid on "shadow pattern" slipjoints: Don't do it. A "shadow pattern" is a style of knife that has no bolster at one or both ends of the knife, just pins throught the liner and [celluloid] scale. Any knife with celluloid scales is most likely old, the celluloid is probably not stable & is probably shrunken or distorted, and will disentegrate if compressed even a little. The only one I ever tightened up was one I peened the pins on, with an itty-bitty punch I made from a nail. The knife wasn't that much tighter when I was done.
Specific brands:
- On Case brand slipjoints, a simple, gentle squeeze in a padded vice works to solve most side-to-side play. Many brands are made like Case: nickel-silver bolsters with nickel-silver pivot pins. I've checked a lot of old brands, and a lot of them can be tightened back up this way. HOWEVER: if you see gaps between solid scales and liners, it probably means that the knife has been twisted or torqued in a way that a permanent fix may not be possible; tightening will only be a temporary solution at best. Note: hollow scale knives, like some old Imperials, might have gaps, but this is normal.
- On some Camillus, which used stainless pivot pins on a lot of their slipjoints & lockbacks, the vice trick works too, but the pins sometimes end up sitting proud of the bolster surface after squeezing in the padded vice. For some Camillus knives I use fine emery cloth and give the bolsters an even, matte finish.
- U.S. Schrade slipjoints are another matter entirely. U.S. Schrades used a patented construction system called the "Swinden Key" system for building most or all of their slipjoints for decades. This simplified the building process, but can make them very frustrating to tighten. (Trying to tighten a couple of old U.S. Schrade slipjoints in a padded vice literally drove me to drink.) The best way I found: I've looked at pictures of old dismantled U.S. Schrade pocket knives, and tightened them with a pair of leather-padded vice grips. I compress different areas of the pivot bolsters, depending on where I thought the 'head' of the pivot pin might be. If you look at a picture of the 'Swinden Key' system, you'll know what I mean. The problem is that the flanged pivot pin head keeps the bolster from tightening up; at least that's my theory. I've had success about half the time with this procedure.
- U.S. Schrade lockbacks: All the U.S. Schrade lockbacks I've seen are built with pin-through-the-bolster construction. On early models like LB7's from the late 70's & early 80's, the blade thickness & spring thickness are pretty much the same. In later production knives, however, there can be variances between blade and lockbar thicknesses. The problem here is that you can squeeze the pivot area down to the point that the lockbar is 'stuck' and can't move; if it does unlock, it stays up, or doesn't lock solidly. The solution of sliding the spine of another LB blade into the top of the joint and gently rocking it to loosen things back up may not work. I have seven U.S. Schrade lockbacks (6OT's, 7OT's, and LB7's), and five later production knives have different blade thicknesses.
- Imperial shell-handled knives: the bolster, which I think is simply plated sheet steel, will buckle and collapse if compressed. The only solution I've found - and I've only done this on one Imperial as an experiment - is to remove the old scales by prying up the tabs at each end of the knife, gently peen the pins with a small brass hammer, and glue on new homemade scales (I used wood.) It was nice & tight when I was done. And really ugly too.
- Ranger and Sabre brand slipjoints: are built along the same concept as the Imperials, but have solid scales; this apparently allowed them to get around the Imperial patent. (Speculation on my part there.) The problem here is that you see solid scales and assume the bolster is solid too. It ain't. I've got a Sabre brand knife that is now nice and tight, but looks like it got run over by a train.
- Vicotrinox: These are built in a way that the pivot pins fit through a small flanged ring; this ring in turn fits inside a molded recess in the handle scale, and holds the scale in place. Smacking or otherwise compressing the scale leads to "Traumatic Scale Death". (I know this from experience.
) Since aftermarket replacement scales are available, I remove the old scales, gently peen the CENTER of the pin - don't touch the flanged ring - and just snap on new Victorinox scales. I either use scales from another knife, or I have several jigs made, so I can just cut new ones out of wood or micarta and glue them on.
- Opinel: Basically, I use padded Channel-Locks and gently squeeze random spots around the ring lock; just 'roll the knife' around and clamp down gently. A few minutes of this usually gets the lock and joint tension where it needs to be for my use. If it ends up too tight, you can use a flat-head screwdriver in the lock-ring slot to spread the slot a little wider. Once tweaked, my Opinels usually stay 'adjusted'.
For stubborn Opinel's that won't stay 'adjusted': I collect old tools, so that's why I had old junky adjustable threading dies to experiment with; also, I was bored. So, this may seem silly, but it worked, and I got to use an old tool that normally sits around collectiing dust. (There has to be a better way to tighten an Opinel.)
Let the knife dry out completely, then oil the joint. (In my experience, Opinel knives only need a tiny drop or two of mineral oil in the joint.) Take an old adjustable threading die with a minimum of four cutters (we called them 'cloverleaf dies' in machine shop in high school), that has a single adjusting screw that spreads the die apart, and put leather or rubber on each threading tooth. Turn the screw to open the die as far as is needed. Put the knife joint (leave the locking ring on) into the die as you would a piece of pipe to be threaded, and slowly turn the screw to let the die 'close' a little. Turn the screw a little each day for about three days. This will compress the joint and eventually tighten it up. Be careful not to go too far, as the ring can deform. I figured this process out because I deformed a ring while compressing an Opinel with padded vice grips. Opinel knives lock with round locking rings, not oval ones.
******
This covers most of the things I've learned; I'll add more as I find my old notes. Feel free to add any ideas or experiences you guys have, and if you think of something that will make any of these things simpler, by all means please post it.
Edited to add: I misspelled "vice" all through this post. It's supposed to be "vise".
~Chris
Tightening joints on slipjoints:
I've seen the question of tightening loose joints on slipjoints – and occasionally lockbacks – come up a few times over the last few years, so I thought I'd put this up. This is lessons I've learned over the years with a lot of the older knives we get here from thrift stores and antique shops. A lot of them are loose, and/or have other issues. Often, all these knives need is simply a little TLC to be "brought back from the dead". (I usually won't mess with fragile or sentimental pieces.) This is in reference to more traditional knives, but it is more in line with this forum, I think.
A few things to remember:
1: Clean out the knife, and oil the joint before any tweaking. Any debris in the joint will just get pressed into the liners, etc. and make things much rougher than before.
2: If you make a knife too tight, you can slip the blade spine of another (identical) knife into the slot at the joint, and gently rock the blade a little. This will loosen it up enough to pivot easily, but hopefully leave it tighter than before.
3: If step 2 is not an option, I use a micrometer on the blade spine at the pivot, and set my feeler gauges to take up the same amount of space when I set up the padded vice. This usually works, but not always.
4: Celluloid on "shadow pattern" slipjoints: Don't do it. A "shadow pattern" is a style of knife that has no bolster at one or both ends of the knife, just pins throught the liner and [celluloid] scale. Any knife with celluloid scales is most likely old, the celluloid is probably not stable & is probably shrunken or distorted, and will disentegrate if compressed even a little. The only one I ever tightened up was one I peened the pins on, with an itty-bitty punch I made from a nail. The knife wasn't that much tighter when I was done.
Specific brands:
- On Case brand slipjoints, a simple, gentle squeeze in a padded vice works to solve most side-to-side play. Many brands are made like Case: nickel-silver bolsters with nickel-silver pivot pins. I've checked a lot of old brands, and a lot of them can be tightened back up this way. HOWEVER: if you see gaps between solid scales and liners, it probably means that the knife has been twisted or torqued in a way that a permanent fix may not be possible; tightening will only be a temporary solution at best. Note: hollow scale knives, like some old Imperials, might have gaps, but this is normal.
- On some Camillus, which used stainless pivot pins on a lot of their slipjoints & lockbacks, the vice trick works too, but the pins sometimes end up sitting proud of the bolster surface after squeezing in the padded vice. For some Camillus knives I use fine emery cloth and give the bolsters an even, matte finish.
- U.S. Schrade slipjoints are another matter entirely. U.S. Schrades used a patented construction system called the "Swinden Key" system for building most or all of their slipjoints for decades. This simplified the building process, but can make them very frustrating to tighten. (Trying to tighten a couple of old U.S. Schrade slipjoints in a padded vice literally drove me to drink.) The best way I found: I've looked at pictures of old dismantled U.S. Schrade pocket knives, and tightened them with a pair of leather-padded vice grips. I compress different areas of the pivot bolsters, depending on where I thought the 'head' of the pivot pin might be. If you look at a picture of the 'Swinden Key' system, you'll know what I mean. The problem is that the flanged pivot pin head keeps the bolster from tightening up; at least that's my theory. I've had success about half the time with this procedure.
- U.S. Schrade lockbacks: All the U.S. Schrade lockbacks I've seen are built with pin-through-the-bolster construction. On early models like LB7's from the late 70's & early 80's, the blade thickness & spring thickness are pretty much the same. In later production knives, however, there can be variances between blade and lockbar thicknesses. The problem here is that you can squeeze the pivot area down to the point that the lockbar is 'stuck' and can't move; if it does unlock, it stays up, or doesn't lock solidly. The solution of sliding the spine of another LB blade into the top of the joint and gently rocking it to loosen things back up may not work. I have seven U.S. Schrade lockbacks (6OT's, 7OT's, and LB7's), and five later production knives have different blade thicknesses.
- Imperial shell-handled knives: the bolster, which I think is simply plated sheet steel, will buckle and collapse if compressed. The only solution I've found - and I've only done this on one Imperial as an experiment - is to remove the old scales by prying up the tabs at each end of the knife, gently peen the pins with a small brass hammer, and glue on new homemade scales (I used wood.) It was nice & tight when I was done. And really ugly too.
- Ranger and Sabre brand slipjoints: are built along the same concept as the Imperials, but have solid scales; this apparently allowed them to get around the Imperial patent. (Speculation on my part there.) The problem here is that you see solid scales and assume the bolster is solid too. It ain't. I've got a Sabre brand knife that is now nice and tight, but looks like it got run over by a train.
- Vicotrinox: These are built in a way that the pivot pins fit through a small flanged ring; this ring in turn fits inside a molded recess in the handle scale, and holds the scale in place. Smacking or otherwise compressing the scale leads to "Traumatic Scale Death". (I know this from experience.
) Since aftermarket replacement scales are available, I remove the old scales, gently peen the CENTER of the pin - don't touch the flanged ring - and just snap on new Victorinox scales. I either use scales from another knife, or I have several jigs made, so I can just cut new ones out of wood or micarta and glue them on.- Opinel: Basically, I use padded Channel-Locks and gently squeeze random spots around the ring lock; just 'roll the knife' around and clamp down gently. A few minutes of this usually gets the lock and joint tension where it needs to be for my use. If it ends up too tight, you can use a flat-head screwdriver in the lock-ring slot to spread the slot a little wider. Once tweaked, my Opinels usually stay 'adjusted'.
For stubborn Opinel's that won't stay 'adjusted': I collect old tools, so that's why I had old junky adjustable threading dies to experiment with; also, I was bored. So, this may seem silly, but it worked, and I got to use an old tool that normally sits around collectiing dust. (There has to be a better way to tighten an Opinel.)
Let the knife dry out completely, then oil the joint. (In my experience, Opinel knives only need a tiny drop or two of mineral oil in the joint.) Take an old adjustable threading die with a minimum of four cutters (we called them 'cloverleaf dies' in machine shop in high school), that has a single adjusting screw that spreads the die apart, and put leather or rubber on each threading tooth. Turn the screw to open the die as far as is needed. Put the knife joint (leave the locking ring on) into the die as you would a piece of pipe to be threaded, and slowly turn the screw to let the die 'close' a little. Turn the screw a little each day for about three days. This will compress the joint and eventually tighten it up. Be careful not to go too far, as the ring can deform. I figured this process out because I deformed a ring while compressing an Opinel with padded vice grips. Opinel knives lock with round locking rings, not oval ones.
******
This covers most of the things I've learned; I'll add more as I find my old notes. Feel free to add any ideas or experiences you guys have, and if you think of something that will make any of these things simpler, by all means please post it.
Edited to add: I misspelled "vice" all through this post. It's supposed to be "vise".
~Chris
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