Question on folder bushings

Billy Helton

Well-Known Member
I have noticed that some makers use bushings for there slip joints. I would like to know some pros and cons of the bushings. The bushings that I have seen will have like a 3/32 ID and maybe a 1/8 OD. Thank you in advance

God Bless
Billy
 

Calvin Robinson

Moderator Christian Forum
I have used them and going by the Tony Bose tutorial they work well, very smooth action. I could not get rid of side to side play in the blade no mater how I tried. I must say however I did not use the barrel lap and lapping compound that he uses in the tutorial. If I had it probably would have worked perfectly.
 

Billy Helton

Well-Known Member
Thank you for the link
I have used them and going by the Tony Bose tutorial they work well, very smooth action. I could not get rid of side to side play in the blade no mater how I tried. I must say however I did not use the barrel lap and lapping compound that he uses in the tutorial. If I had it probably would have worked perfectly.
Thanks calvin I might have to try these.
 

Cubane

Well-Known Member
I have been doing the same thing. To stop blade wobble I make sure the bushing is only 0.001 inches thicker than the blade. I haven't used a barrel lap before. I use an old reamer after HT to make sure all the scale is gone from the inside of the pivot hole, that is about it.

The only con that I know about is the increased construction difficult.

Alistair
 

mike miller

KNIFE MAKER
Don't have a lapper just hand grind them down close then hand sand. If you are going to use them a lot I have seen plates made with varying depth holes in them that are heat treated. you stick a bushing in a known dept hole and use disc grind to grind down to plate for a known size.
 

Sean Cochran

Well-Known Member
I know Tony uses the bushing (Reese Bose doesnt use them) but Im not fully sold on them. I think the biggest con is like Alistair said, it increases assembly and adds steps to the process that if not done properly will lead to a bad fit up. Ive handled knives with them (one of Tony's). I honestly cant tell a huge difference in the smoothness of the knife.
I have a suspiscion that one of the biggest reasons for the bushing is you can really set the pivot pin hard and not lock up the blade.


Just my .02$

Sean
 

Cubane

Well-Known Member
I have a suspicion that one of the biggest reasons for the bushing is you can really set the pivot pin hard and not lock up the blade.

Sean
Yes that is a good one. To get the bushing down to size I use a little plate with a 3/16 hole in it. I have a 3/16 shaft that I use to push down on the bushing so it is always being sanded away. I also put the blade and some shim on the shaft so I know when I get the correct thickness. If that doesn't make sense I can post a picture later.

Alistair
 

Billy Helton

Well-Known Member
Thank you guys for the tips. So if im understanding this right you can peen the pins a little harder . This would help me I struggle with stainless pins. Once again thanks to you all.
 

Sean Cochran

Well-Known Member
Billy, I have never used the bushings so I wonts say for sure, but with the bushing it seems you could peen a little harder because the liner is going to hit the bushing not the blade if the bushing is .001 bigger than the blade. This would give you a .002 space for blade to travel.
If you are having trouble hiding the pin this is really not the solution, the best thing I did was to get a tapered reamer to use on the pivot hole. Tracy sells them. Since ive been using the reamer I have been able to hide the pin every time. The problem I was having was I could hide the pin, then after opening the knife a few times it would show back up. The reason is because I was swelling the pin in the blade. This is where the reamer helped me, by creating some extra space in the pivot hole it allows the pin to swell in the hole, not the blade. Does that make sense?

Like I said before Im not sold on the bushings, but I say that without having tried it. I have only handled a knife with one.

Sean
 

Brent D. Cramer

Well-Known Member
Bushings are the way to go! Keep close tolerances +or - .0005

Be sure to lap the hole.

I buy the 3/16" od and 3/32" id from k&g.
 
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Calvin Robinson

Moderator Christian Forum
Billy, I have never used the bushings so I wonts say for sure, but with the bushing it seems you could peen a little harder because the liner is going to hit the bushing not the blade if the bushing is .001 bigger than the blade. This would give you a .002 space for blade to travel.
If you are having trouble hiding the pin this is really not the solution, the best thing I did was to get a tapered reamer to use on the pivot hole. Tracy sells them. Since ive been using the reamer I have been able to hide the pin every time. The problem I was having was I could hide the pin, then after opening the knife a few times it would show back up. The reason is because I was swelling the pin in the blade. This is where the reamer helped me, by creating some extra space in the pivot hole it allows the pin to swell in the hole, not the blade. Does that make sense?

Like I said before Im not sold on the bushings, but I say that without having tried it. I have only handled a knife with one.

Sean
Do you use the taperd reamer in the pivot hole of the blade? If so please explain. If it helps to hide the pin and not have it show up again after a little use I'm sure every one would like to know how its done.
 

Sean Cochran

Well-Known Member
I guess I was kinda vague.:eek: To answer, no. I drill the hole in the blade with a #43 bit and then ream to size. Tracy has a good deal on them.
I also drill and ream the pivot holes in the bolster along with the spring pin holes with the same bit. Once I have done all my test fitting and finished the bolster to 95% I use the tapered reamer turned by hand just a few turns, just enough to give the pin some room to expand. This has worked for me so far. Hope this helps.

Sean
 

Billy Helton

Well-Known Member
Bushings are the way to go! Keep close tolerances +or - .0005

Be sure to lap the hole.

I buy the 3/16" od and 3/32" id from k&g.
Thanks brent I will try this
Billy, I have never used the bushings so I wonts say for sure, but with the bushing it seems you could peen a little harder because the liner is going to hit the bushing not the blade if the bushing is .001 bigger than the blade. This would give you a .002 space for blade to travel.
If you are having trouble hiding the pin this is really not the solution, the best thing I did was to get a tapered reamer to use on the pivot hole. Tracy sells them. Since ive been using the reamer I have been able to hide the pin every time. The problem I was having was I could hide the pin, then after opening the knife a few times it would show back up. The reason is because I was swelling the pin in the blade. This is where the reamer helped me, by creating some extra space in the pivot hole it allows the pin to swell in the hole, not the blade. Does that make sense?

Like I said before Im not sold on the bushings, but I say that without having tried it. I have only handled a knife with one.

Sean
Well sean thanks for your input on this one I will try the reamer I have tryed a reamer before but I think the angle was too much I will look up the one tracy sells Thanks
 

Sean Cochran

Well-Known Member
No problem Billy. Dont get me wrong im not knocking the bushing method. It is just my understanding that the theory is by using the bushing you are providing greater surface area for the rotation of the blade and decreasing wear. In the past most knives had N/S bolsters and pins so there is no doubt the bushing would provide more wear resistance. I usually use 416 SS for bolsters and pins which is harder than N/S. I use .002 spacers on each side of the blade while peening to give .004 clearance for the blade to pivot.
Ill be honest, I do it this way mostly because the guy who taught me does it that way and it his knives are darn near perfect, so I figured if it aint broke.....

Anyway just my .02$ on it. Let me know if you do the bushings how it works out for you. Im going to have to give it a try i guess.

Sean
 

Brent D. Cramer

Well-Known Member
I started out in '05 just peening with no bushings. Tony showed me how to use the bushings and I've never looked back. Once you do it you will love that you can literally pound the Crap out of the pivot pin (with in reason) and the clearance remains consistent.

I use a 10 degree reamer and ream about half the hole.
The smoothness of the action depends on the tang shape and the way its finished as much as the pivot.

I hope this helps.
 

Bruce Bump

Forum Owner-Moderator
I started out in '05 just peening with no bushings. Tony showed me how to use the bushings and I've never looked back. Once you do it you will love that you can literally pound the Crap out of the pivot pin (with in reason) and the clearance remains consistent.

I use a 10 degree reamer and ream about half the hole.
The smoothness of the action depends on the tang shape and the way its finished as much as the pivot.

I hope this helps.
Yep, me too. If T Bose does it this way B Bump does it this way. He is the king of slippies.
I do wish they made smaller bushings for smaller tangs. I'm working on a peanut model right now and cant use a bushing. I'm sweating it too.
 

Brent D. Cramer

Well-Known Member
Yep, me too. If T Bose does it this way B Bump does it this way. He is the king of slippies.
I do wish they made smaller bushings for smaller tangs. I'm working on a peanut model right now and cant use a bushing. I'm sweating it too.
I feel your pain Bruce! I've thought about just making some out of stainless. I know its not a bearing material but it would work for a small knife.

I have got a peanut on my list for next month and I'm already loosing sleep about it. I'll be praying for you. (I think He cares about everything!) Let me know how it turns out.
 
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