Snappy slipjoint folder

[jbib]

I have a very nice slip joint folder. However, every time I open it I fear I may rip off a thumbnail. If I endure this long enough should I expect action to loosen up. Given that there no screws is there any other action to ease the way to snappy action?

 

[afishhunter]

What knife so you have?

You can try:
1) Cleaning in hot (if you can put your hand in the water without being burned or boiled like a lobster or crawdad, it isn't hot enough to affect the heat treat) soapy water with a toothbrush and opening/closing the blade while under the water. NOTE: Wraping a rag over the blade makes it easier to open/close while preventing the blade fully closing, and it prevents cuts.
Rinse under warm/hot water, while opening and closing the blade.
Dry the joint(s) with compressed air (canned or from a shop compressor) or aerosol WD-40, and lube the joint(s) with the oil of your choice.
Forget "food safe". There isn't enough on the blade to matter, if you wipe off the excess.
Over the last 64/65 years I have used new and used motor oil, 2 stroke oil, transmission fluid (Dextron and "F"), 3 In One, Hoppie' #9, olive oil, honing oil ... whatever I had on hand, with less than zero health issues.
It MAY take more than one washing.

2) Inspect for blade rub against another blade and the liners.
If the blade rub between blades is severe (blade being closed moves sideways) you can use a diamond jewler's file or diamond plate to either make a swedge or extend the existing swedge.
(I have a Marbles D2 stockman that the Spey/Small Game Skinner/Budding/Grafting blade was hitting the sheepsfoot near the tip. Before filing a swedge on the multi use Spey blade, its pull required using a tool to raise that blade. After filing the pull is a smooth "5" (about the same as a SAK)

3) Inspect the tang with the blade open. IF the tang has a 90° edge, you can use a diamond jewler's file to slightly ease/radius that 90° edge, making it easier to start moving the backspring. A radiused edge moves the backspring gradually, not all at once.

Lastly, it is possible the knife was made with heavier than needed backsprings. (The backspring's only job is to prevent the blade from partly opening in your pocket, and flopping partly closed between cuts/slices when the knife is in use. The Buck 301/303 is known for having "soft" backsprings, with a pull aroun "3" to "4".
Some dislike the "soft" pull. Personally, I like it. The backsrings do their job, AND I don't have to fight with the knife to open it when my hands are cold and/or wet.
I have never seen any logical reason(s) to fight my knife to use it.

I have an A. Wright & Son knife that is equipped with a pull between "8" and "9". Much heavier than I like.
The blade is pinchable (barely) so it does get pocket time and used.
The heavy pull is by design.
"Someday" I might send it to a modder to have the pull lightened by grinding a little off the backside of the spring so it can flex easier, and recovered. (I "think" Stag, Ram Horn or Warthog Ivory would look good.)

 

[ea42]

The only way to effectively weaken the pull (assuming everything is cleaned and lubed and the blade isn't being overly pinched by the liners) is to grind some material off the backspring. That's about the safest bet. You could also hyperextend the spring by putting a wedge between the spring and tang square and forcing the blade open but you risk breaking the spring this way.

Eric

 

[jbib]

Great advice, I am going to inquire on who may provide this service.

 

[jbib]

The only way to effectively weaken the pull (assuming everything is cleaned and lubed and the blade isn't being overly pinched by the liners) is to grind some material off the backspring. That's about the safest bet. You could also hyperextend the spring by putting a wedge between the spring and tang square and forcing the blade open but you risk breaking the spring this way.

Eric

Since I'm a neophyte on this I would like to ask a question. If I partially open the slip joint so that if you look at it, is a 90 degree angle. If i look at the end of the blade that abuts what I think you refer as the backspring are you suggesting that I place the wedge between the the backspring and the end of the blade and "kinda" force it open. And just let it set like that for awhile? BTW again I thank you both for the free advice, it's great! If you ever have any accounting or tax question you know how to contact me!

 

[euroken]

Since I'm a neophyte on this I would like to ask a question. If I partially open the slip joint so that if you look at it, is a 90 degree angle. If i look at the end of the blade that abuts what I think you refer as the backspring are you suggesting that I place the wedge between the the backspring and the end of the blade and "kinda" force it open. And just let it set like that for awhile? BTW again I thank you both for the free advice, it's great! If you ever have any accounting or tax question you know how to contact me!

You'll find a LOT of great advices and insights on this forum for sure!

I have weaken the pull on couple of my slip joints in the past by what ea42 suggested. What I did was to cut off of the bulb end of the straight leg of a bobby pin to squeeze it in between the tang and the back spring. It was thin enough AND the pin is stiff enough to be wedged in. I left it in there over night and the next day it was enough to weaken the pull to my liking! Now, I have no idea how strong the pull is on your knife but this may just do it. I wouldn't put anything in thicker as it could break the spring as ea42 suggests.

Another way is a bit more involved but I have done this on my A. Wright lambsfoot (A. Wright and sons knives have been known for uber stiff pulls). It is to get a tiny file and lightly round of the Torque points shown on the picture below. That 'eases' the initial pull of the blade but maintain the opening and closing snap. Again, do it just a tad bit at a time.

Regardless, good luck to you and would love to see some pictures if you have a moment!

 

[jbib]

You'll find a LOT of great advices and insights on this forum for sure!

I have weaken the pull on couple of my slip joints in the past by what ea42 suggested. What I did was to cut off of the bulb end of the straight leg of a bobby pin to squeeze it in between the tang and the back spring. It was thin enough AND the pin is stiff enough to be wedged in. I left it in there over night and the next day it was enough to weaken the pull to my liking! Now, I have no idea how strong the pull is on your knife but this may just do it. I wouldn't put anything in thicker as it could break the spring as ea42 suggests.

Another way is a bit more involved but I have done this on my A. Wright lambsfoot (A. Wright and sons knives have been known for uber stiff pulls). It is to get a tiny file and lightly round of the Torque points shown on the picture below. That 'eases' the initial pull of the blade but maintain the opening and closing snap. Again, do it just a tad bit at a time.

Regardless, good luck to you and would love to see some pictures if you have a moment!

WOW! very much appreciated!

 

[SharpBits]

I did a gentle easing of the torque point on one of my A. Wright knives. It was just enough to make it easier to open, while maintaining the strong spring. Just a light touch, otherwise you can mess up your knife.

 

[Ben Kabisch]

depending on the knife, i would just grind a little off the backspring until the tension was where i liked and then refinish the spine

 

[ken erickson]

I have a very nice slip joint folder. However, every time I open it I fear I may rip off a thumbnail. If I endure this long enough should I expect action to loosen up. Given that there no screws is there any other action to ease the way to snappy action?

I am curious , is your knife a single or multi-blade and or have half stops?

You mentioned it is a "very nice slip joint folder" and while the suggestions above may or will lesson the amount of effort to open there are some concerns. IMHO there is no remedy that involves removing either back spring material or removing material from the tang ie "torque points" that will not change the back spring being flush in closed, half stop if it has one, and open position. Removing material from either can even change how far the blade opens or even cause blade tip or blade to hit the inside of the spring when closed.

I am not suggesting that you dont try any of the suggestions but do want you to be aware just how easy it is to change the geometry of the tang to back spring.

 

[afishhunter]

IMHO there is no remedy that involves removing either back spring material or removing material from the tang ie "torque points" that will not change the back spring being flush in closed, half stop if it has one, and open position. Removing material from either can even change how far the blade opens or even cause blade tip or blade to hit the inside of the spring when closed.

Removing material from the corner of the opening torque point does not affect the spring height when open. It is on top and facing the bladewell when open. (allowing a short stroke with the jeweler's file. A ~45° angle works well to ease that corner.)
It also does not affect proud/sunken when closed, because the blade tang behind the torque point is in contact with the backspring, not the torque point.
It does not take much metal removal to make a huge differance in the pull. You just have to get rid of the sharp corner of the opening torque point and the flat or round tang end.

As for grinding or filing the backspring to thin it, AND/OR to ease the CLOSING torque point angle (not accessable when the knife is assembled.) I would take the knife apart (new pins will be required) and grind or file between the pivot pin hole and the raised portion of the spring the tang contacts, on the inside/rear/top of the spring visible inside the blade well. That will not change the spring height in any position.
(If you grind, go slow and keep it cool to not affect the heat treat of the spring. Personally, I would use a file.)
Work slow, and check the pull as you work, cuz it will not require taking off a lot of metal. I would also slightly ease the long edges (1 or 2 passes each side edge with the file at 75°~80° or so) to remove the 90° stress raiser, and any burrs along the length of the spring.

I would not try to thin the spring by grinding or filing the visible part of the spring, especially on a multi spring knife, since that would lower the pull of the other blades, which MAY be "spot on" for the pull, and would also grind/file the liners, bolsters, and covers, along with the springs.

I forgot to mention in my first post:
IF the knife is a pre-2004 US made Schrade, Old Timer, or Uncle Henry, with Swindon Key construction (pretty much any Schrade and Uncle Henry, and at least the Old Timer 8OT and 858OT, I'm not sure about which other models have it.) FORGET taking the knife apart!!!! They don't have through pins. It takes a lot of work and time to convert to pins.

I think you can check if a Swindon Key knife (if you cannot see any pins) by rubbing the bolster briskly with a rag.
You MAY need a jewler's lupe to see the pins after rubbing. You WILL need good lighting to see the faint line of the pins. You can "play it safe" and just presume any Old Timer that you can't readily see pivot pins on has Swindon Keys.
As far as I know Imperial, Camillus, and Ulster didn't make any Swindon Key knives.
NO other manufacturer used or uses Swindon Keys, even after the patent expired.

The post 2004 "Taylor-Schrade" and "BTI-Schrade" offshore knives have through pins. AFAIK the current US made BTI Schrade knives use through pins.

 

[ea42]

I am curious , is your knife a single or multi-blade and or have half stops?

You mentioned it is a "very nice slip joint folder" and while the suggestions above may or will lesson the amount of effort to open there are some concerns. IMHO there is no remedy that involves removing either back spring material or removing material from the tang ie "torque points" that will not change the back spring being flush in closed, half stop if it has one, and open position. Removing material from either can even change how far the blade opens or even cause blade tip or blade to hit the inside of the spring when closed.

I am not suggesting that you dont try any of the suggestions but do want you to be aware just how easy it is to change the geometry of the tang to back spring.

Ken I'm glad you brought that up. I should have mentioned that if removing backspring material to grind only the area from about halfway between the center pin and the end of the spring and back. I wouldn't remove anything near end of the spring, but would instead feather almost up to that point. All kinds of nasty issues can crop up if material is removed from the end of the spring, especially if the spring end and/or tang square are cut at an angle which is pretty standard. It's definitely a Pandora's Box nobody wants to have to deal with. This is definitely a bit of a tricky fix for sure, especially for someone who hasn't worked on knives before as you have to be very careful with how much is removed and you want to keep the back symmetrical with how it was and not produce any slight valleys where they shouldn't be. Often a few swipes with a 180 belt will be enough. Also should have mentioned that this is really only viable for a single blade knife since as Steve mentioned if you have two springs there you'd be taking material off both springs and affecting the pull on both blades.

Steve removing material from either of the tang points would definitely cause the spring to drop a bit as the spring rests right on those points in the open and closed position. Removing material on the front tang point (which rests on the spring when the blade is closed) will not only drop the spring a bit but will also raise the blade tip. If it peaks over the liners you'd have to take a bit off the kick which will drop the spring even further so you have a double whammy there. All things to keep in mind.

Swinden construction is actually very easy to disassemble. just remove the center pin and give the right and left sides a twist to line up the keyholes and the knife comes right apart. If you need to separate the blades and springs it's another story though.

Eric

 

[Oldy]

I had a 9 pull on a 73,i opened the knife 3/4 and took a close hanger end and slid it between the covers and under the kick,I then closed the knife on the wire until the spring was stretched past twice it's normal point,and left it for a few days,it is now a 7 tops.i probably didn't explain it well lol

 

[Signalprick]

Is this a custom or a factory knife?

 

[afishhunter]

Steve removing material from either of the tang points would definitely cause the spring to drop a bit as the spring rests right on those points in the open and closed position

Agree. That is why I said to file/grind up to where the tang contacts the spring - NOT where it contacts the spring.

As for the torque points, they are only contacting the spring when opening/closing the blade. Removing the sharp corner of the torque point does not affect spring height when open or closed.
I have had to do that on a couple of my knives. The spring was still flush after I finished.

 

[jbib]

You'll find a LOT of great advices and insights on this forum for sure!

I have weaken the pull on couple of my slip joints in the past by what ea42 suggested. What I did was to cut off of the bulb end of the straight leg of a bobby pin to squeeze it in between the tang and the back spring. It was thin enough AND the pin is stiff enough to be wedged in. I left it in there over night and the next day it was enough to weaken the pull to my liking! Now, I have no idea how strong the pull is on your knife but this may just do it. I wouldn't put anything in thicker as it could break the spring as ea42 suggests.

Another way is a bit more involved but I have done this on my A. Wright lambsfoot (A. Wright and sons knives have been known for uber stiff pulls). It is to get a tiny file and lightly round of the Torque points shown on the picture below. That 'eases' the initial pull of the blade but maintain the opening and closing snap. Again, do it just a tad bit at a time.

Regardless, good luck to you and would love to see some pictures if you have a moment!

Regardless of what you said, here's how I heard it. Cut off the tip of the bobby pin; insert the tip of the bobby pin between the backstop and the backspring; wait for some period of time and see what happens. (if I didn't understand it's on me). Real big thanks for taking the time, Euro!!!

 

[jbib]

Is this a custom or a factory knife?

Rosecraft, it comes from that place I don't like to support but I guess I was seduced.

 

[jbib]

Ken I'm glad you brought that up. I should have mentioned that if removing backspring material to grind only the area from about halfway between the center pin and the end of the spring and back. I wouldn't remove anything near end of the spring, but would instead feather almost up to that point. All kinds of nasty issues can crop up if material is removed from the end of the spring, especially if the spring end and/or tang square are cut at an angle which is pretty standard. It's definitely a Pandora's Box nobody wants to have to deal with. This is definitely a bit of a tricky fix for sure, especially for someone who hasn't worked on knives before as you have to be very careful with how much is removed and you want to keep the back symmetrical with how it was and not produce any slight valleys where they shouldn't be. Often a few swipes with a 180 belt will be enough. Also should have mentioned that this is really only viable for a single blade knife since as Steve mentioned if you have two springs there you'd be taking material off both springs and affecting the pull on both blades.

Steve removing material from either of the tang points would definitely cause the spring to drop a bit as the spring rests right on those points in the open and closed position. Removing material on the front tang point (which rests on the spring when the blade is closed) will not only drop the spring a bit but will also raise the blade tip. If it peaks over the liners you'd have to take a bit off the kick which will drop the spring even further so you have a double whammy there. All things to keep in mind.

Swinden construction is actually very easy to disassemble. just remove the center pin and give the right and left sides a twist to line up the keyholes and the knife comes right apart. If you need to separate the blades and springs it's another story though.

Eric

You gentlemen are talking like a couple of brain surgeons while I haven't even taken CPR! Regardless, I find your dialogue fascinating.

 

[jbib]

I am curious , is your knife a single or multi-blade and or have half stops?

You mentioned it is a "very nice slip joint folder" and while the suggestions above may or will lesson the amount of effort to open there are some concerns. IMHO there is no remedy that involves removing either back spring material or removing material from the tang ie "torque points" that will not change the back spring being flush in closed, half stop if it has one, and open position. Removing material from either can even change how far the blade opens or even cause blade tip or blade to hit the inside of the spring when closed.

I am not suggesting that you dont try any of the suggestions but do want you to be aware just how easy it is to change the geometry of the tang to back spring.

I didn't mean "Made in USA" nice, that runs in the hundreds of dollars but I purchased a Rosecraft that is extremely nice.

 

[jbib]

If I haven't contacted you directly please let me thank all of you who took the time to share your thoughts!