How to untighten a slip joint?

[Andybrock]

I made my first slip joint using a bushing, and through my own carelessness getting carried away with the hammer making sure the pin was well bedded into the bolsters so it didn’t show now it’s tight opening and closing. What’s the best way to loosen it off a touch?

 

[Danke42]

Cutler's Stiddy with a liner spreader would probably do it. Maybe worth finding if you plan to make lots of knives like that.

 

[Hengelo_77]

Tony Bose has a vid on YouTube on that.
Basicaly place the ricasso on an anvil at app. 45 degrees and hit the spine with a rubber hamer.
Worked for me

 

[AVigil]

If you beat it to much, the pin has swollen so much chances are you will not be able to slacken the blade and may break it trying to do so.

Ask me how I know this.
You probably should drill the pin with a much smaller drill bit on both sides, grind off the mushroom head and then try to drive the pin out.

Only peen the blade until the blade does not have side play.
Then open and close the blade many times then check if there is still play, do this until there is no blade play.

Then and only then grind the pins flush.

 

[Signalprick]

Like Adam said, grind the pin flush then open to half stop and slacken the blade. This will reveal your pin and raise any remaining mushroom bevel. You should have little to no issue driving it through and redoing.

 

[Drew Riley]

 

[David Schott]

If you beat it to much, the pin has swollen so much chances are you will not be able to slacken the blade and may break it trying to do so.

I'm curious about this with a bushing construction like he said. Assuming the bushing is the right size wider than the blade, wouldnt "overhammering" be effectively impossible? Once the bushing is seated/locked against the liners square, even if you were to completely deform the pin within that bushing, the blade simply rotates around the OD of that bushing regardless, no? The bushing really can't keep any orientation but square to the tang.

Perhaps with crazy smashing you can deform the liners themselves in some way that causes the blade to get pinched?

I only ask because since I went to bushings, I really hammer the F out of pivot pins if they are using bolsters and I've never had one bind. I even put the pins in my milling machine vice and "press" them with such force that they create an actual, flat rivet.

 

[Signalprick]

I'm curious about this with a bushing construction like he said. Assuming the bushing is the right size wider than the blade, wouldnt "overhammering" be effectively impossible? Once the bushing is seated/locked against the liners square, even if you were to completely deform the pin within that bushing, the blade simply rotates around the OD of that bushing regardless, no? The bushing really can't keep any orientation but square to the tang.

Perhaps with crazy smashing you can deform the liners themselves in some way that causes the blade to get pinched?

I only ask because since I went to bushings, I really hammer the F out of pivot pins if they are using bolsters and I've never had one bind. I even put the pins in my milling machine vice and "press" them with such force that they create an actual, flat rivet.

It'll flex the handle and crack your cover material. Even micarta. I also learned this from experience.

 

[David Schott]

It'll flex the handle and crack your cover material. Even micarta. I also learned this from experience.

I understand you can crack handles over peening but what would cause blade binding with a bushing construction? Actal torque on the liners to a degree that bushing is no longer square in some way? If blade is square to bushing and bushing square to liners i’m missing what binds preventing the blade from rotating around the bushing. The bushing is mechanically wider than the blade and your liners are theoretically relieved outside a small “washer” around where the bushing is locked.

 

[AVigil]

I use bushing and yes you can lock up a blade if you hammer past where you should.
You are only leaving .0005" on each side and you can do it.

It has been done by people more then once.

 

[Signalprick]

I understand you can crack handles over peening but what would cause blade binding with a bushing construction? Actal torque on the liners to a degree that bushing is no longer square in some way? If blade is square to bushing and bushing square to liners i’m missing what binds preventing the blade from rotating around the bushing. The bushing is mechanically wider than the blade and your liners are theoretically relieved outside a small “washer” around where the bushing is locked.

I see what your saying. I misinterpreted it the first time I read it in conjunction with quoting Adam's post. My only thought would be that perhaps his bushing it too thin? I know that when I left them .001 over the thickest reading on the tang as Mr. Bose instruceted in his tutorial that it seemed too thick and there was always play. I've been taking them down to .00065 - .00075 over my thickest tang reading and they have been coming out perfect with no play. So perhaps, maybe his was thinner yet or his mic readings were off?

 

[David Schott]

I use bushing and yes you can lock up a blade if you hammer past where you should.
You are only leaving .0005" on each side and you can do it.

It has been done by people more then once.

Makes sense and I'm sure more or less prone depending onliner material and how much it can deform! In that case I am sure I'll screw it up eventually. I find myself really smashing the pivot pins on anything with a bolster or integral liners. The reality is with a bushing I probably need to hit it even less and the pins will stay hidden since there's far less stress on the actual pin itself once the bushing locks in place vs one where the blade is in constant pressure on the same pin you want to stay hidden every time it opens and closes!

One erroneous hammer whack off that pin onto the handle can certainly skew some things, too.

Bushings made things a lot less stressful but I still don't look forward to taking that hammer to the final parts, especially more fragile materials.

 

[Pinoy Knife]

the high likely hood is the bushing is too small or there are no washers supporting the bushing going around the hole in the blade.
you can make a couple sacrificial shims out of .003 machinist shim stock, slip them between the blade and frame and open the blade a few times to streetch
it "the pin" a little not the perfect way but might save your bacon here. if you have washers in place you will likely score or destroy them .
forcing you to un do the pin and re do the bushing...a few guys have used these sacrificial shims in place as they peen the pins to prevent over doing it..
these are just my Opinions/Advise and you do not have to agree...

 

[David Schott]

I know that when I left them .001 over the thickest reading on the tang as Mr. Bose instruceted in his tutorial that it seemed too thick and there was always play. I've been taking them down to .00065 - .00075 over my thickest tang reading and they have been coming out perfect with no play.

I have been doing .0005 or so but I havent been using a SG till now and probably had more total variation in all four dimensions of my tang so its could be less or more by a few tenthousanths which I've never been able to feel.

 

[Andybrock]

I understand you can crack handles over peening but what would cause blade binding with a bushing construction? Actal torque on the liners to a degree that bushing is no longer square in some way? If blade is square to bushing and bushing square to liners i’m missing what binds preventing the blade from rotating around the bushing. The bushing is mechanically wider than the blade and your liners are theoretically relieved outside a small “washer” around where the bushing is locked.

I think it was just me being over keen with the hammer, I relieved the liners and lapped the bushing so it was 0.03mm wider than the blade so all should have been good. I’ll be more careful with the next one, all a good learning curve!