Free P4 pliers stiffness after moderate or heavy use

[nitram]

I’ll give mine a really hard squeeze tomorrow to see what happens. Maybe I didn’t fix it after all?

[AimlessWanderer]

If I had to guess (and without taking an angle grinder to one, that's all I can do), I'd say it's due to the shave of the void that the plier rivet is formed into. Specifically, having too obtuse an angle at the bottom of the void.

Excuse the quality of the attached sketch, it was just freehand. Note on the top illustration, the void is a 90^o countersink. This leaves a 45^o angle on rivet and plier head from the plane on which the two halves of the plier head rub. Squeezing the pliers forces each half of the plier head in a shear action onto either side of the rivet, wedging the upper plier half between the lower plier half, and the 45^o angle of the rivet head. At 45^o or larger, the head shouldn't lock.

On the second illustration, a 120^o or larger countersink, would leave a 30^o included angle or less between mating plier faces and the rivet head. The smaller that angle, the more it will lock up like a Morse taper. Polishing it won't help either. It will just increase the amount of surface area in contact, and possibly make it worse - unless the vertical play is greater than the horizontal play.

This is all purely speculative, and one would hope that a 30+ year manufacturer of pliers wouldn't make such a fundamental error, that the numpty typing this, who's never made a pair of pliers in his life, can spot. 

So, as I say, this is complete guesswork, and I might be barking up a lamppost, mistaking it for a tree. If however I am right, this needs a fundamental redesign. As for fixing pliers you already own, the only solution I can think of is to stretch/sprain the rivet pin, so those two faces are slightly too far apart to jam up in. However, this would also adversely affect wire cutting, particularly on fine stranded wire.

[AimlessWanderer]

Note, a bent rivet pin could lead to the same issue, but without knowing which way it's bent, you wouldn't know where to whack it to improve matters.

[Max Stone]

I see you reasoning AL. It does appear the halves are getting pressed together, probably as a result of the countersink head exerting a force at an angle to the squeezing plane.

I do see this as an engineering flaw, as this cannot be considered QC oversight or random defect. It's baked into the design, as far too many are reporting the issue.

It means that I could never recommend the P2 or P4, unless Leatherman came out with a statement/recall addressing the issue.

Very sad, as even with all its problems (magnets, tool/blade deployment, handle hot spots, poor balance, clackety noise), it's grown on me. 

[AimlessWanderer]

If I was going to attempt to fix them, here's what I would try...

WARNING! THIS MAY DESTROY THE PLIERS!!!

... don't say you weren't warned! 

Firstly, get the pliers the right way up. On one plier half, the rivet stays fixed to the head, and on the other half, the head pivots around the rivet. You want the fixed side down, and the moving side up. With the pliers open, support the uppermost half of the pliers only. Vice jaws might be the easiest way. If you wallop the rivet in this position, both the pivot and lower half of the jaws can move downwards. (see attached pic)

In order to direct the force accurately, I'd use two ball pein hammers. One would be placed ball down, directly in the centre of the rivet, with the hammer face pointing up. When you slap that face with the second hammer, the ball will force into the centre of the rivet, hopefully distorting it enough to create a little more play between the two mating plier faces.

BUT THESE ARE CAST PLIER HEADS, AND YOU MIGHT SNAP A JAW OFF! 

In effect, this is a reversal of the repair where you use a centre punch around the periphery of the rivet head, to reduce that working space in which the movable jaw turns. You want to try to create a little more space, so it doesn't jam up. Just like with the centre punch repair, you don't want to bray the life out of it and end up clamping the two halves solid, just bed it in gently, a little at a time, and check often.

IF YOU BUST THEM AND VOID THE WARRANTY, DON'T COME RUNNING TO ME!!!

Three warnings should be enough, I reckon  Obviously, this all works on my assumption on what the underlying problem is, which may or may not be correct  The safest option (and recommended course of action)  is of course to send the smurfing things back to the smurfing muppets that smurfed them up in the first place!!!

[Don Pablo]

Beautiful and clear diagrams, Al.
If locking taper ever comes up in school I'll think of your diagram.

[McStitchy]

As do I 
Your theorie is sound Al 

[Olives666]

Had the same problem with the pliers seizing on my P2, but I also had the same problem with pliers seizing when pressure applied with my Rebar, Wave Gen 2, Wave plus, Charge Plus and Surge to name a few. Older Leatherman pliers ie- Fuse, OG Supertool, gen 1 Wave, etc don’t have that problem at all.
I managed to fix all my troublesome pliers, inc the Free P2 by clamping one side of the plier’s jaws in a vice(with pads) and using a hammer and large punch or  flat drift to hit either side of the pivot on the inside of the unsupported plier. Also applying heat via a heat gun or gas to the pivot area prior to tapping the sides of the plier. Therefore freeing up the pliers. Each time checking the pliers along the way by squeezing the pliers to check for seizing, until it gets to a point where they don’t seize up anymore.
Also while heating the plier head I added a decent oil - I used wet finish line chain oil or Morgan blue race oil (medium thickness) and worked it into the pivot on both sides and into the plier from all sides, while hot and working the pliers up and down while one side clamped in the vice. Then wait for it to cool down, clean up then relive with a decent fine lube/oil.
Pain to do but they now run smooth with no play.

[Olives666]

I also removed the replaceable cutters so they didn’t interfere with each other when the pliers were closed more, otherwise you’ll damage the cutters/pliers when trying to tap apart/free up the pliers.

[nitram]

Polishing it won't help either.

You might be on to something. I did what any sane tool enthusiast would do. I grabbed my morning coffee, my P2 and some thick steel wire and started cutting and bending. You are right, it's very tight once again.

This is disappointing, especially for a tool at this price point.

I bought this one right after they went on sale here. Do we know if this only happens to early production runs? Probably not if it really does turn out to be a design flaw.

[AimlessWanderer]

Although me and Olives666 have offered two different methods of stretching the rivet slightly, I would still recommend returning the defective tools to Leatherman wherever practical to do so. If customers continue to accommodate their failings, Leatherman will be under little pressure to make the necessary changes to ensure this doesn't happen again. For the money their tools sell for, they should be right when they come out of the box, and nobody should have to bash anything with a hammer. The more tools that are returned to them, the higher the incentive for them to address the root causes, and stop sending out tools with these kind of issues.

[SteveC]

 

[tango44]

I agree, but with my first P2 they just canged for one in the same condition.
I have contacted Leatherman about the issue and they just answer: You are welcome to send to our warranty program and thats it.
Both of the tools that have the same problem where made in 06/19 I wonder if other people have newer tools with the same problem?
I don't think Leatherman is giving the attention or level of importance to this issue.
I hope  they do it soon.

[AimlessWanderer]

I agree, but with my first P2 they just canged for one in the same condition.
<snip>
I don't think Leatherman is giving the attention or level of importance to this issue.

That's why customers need to keep sending them back. Every time.

Leatherman clearly think these are acceptable. Customers clearly do not.
I personally agree with the customers. These are poorly designed/made.

Leatherman need to be told that this level of quality is unacceptable, and the only way to do that, is keep sending back every single tool that is not up to the standard expected of a tool at that price. They'll get the message eventually. Social media users should spread the word too, including links back to this thread, so they have a couple of options to try, should they choose to attempt correction themselves (not all countries have the same level of warranty support).

[Aloha]

This is very disappointing.  LMs response is to send a new tool out under warranty  .  They should also be paying for you to do that as well since its clearly a issue on their part. 

What's so darn funny is how much they belittled the other offerings ( well that one tattooed guy did ) when announcing this stool ( no typo ). 

When I see the grey sheath I'll know the pliers bind up, while my tool in the black sheath performs wonderfully.   

[SirVicaLot]

He forgot that part, where the pliers become unusable after use...

Marketing BS, what do you expect? I don‘t believe any marketing videos I see from manufacturers. Of course they only show you the good stuff. Reviews should be done by independent parties. You just have to make sure they are really independent, and didn‘t „forget“ to mention that they got money for that review...

[Aloha]

 

[AimlessWanderer]

This is very disappointing.  LMs response is to send a new tool out under warranty  .  They should also be paying for you to do that as well since its clearly a issue on their part. 

What's so darn funny is how much they belittled the other offerings ( well that one tattooed guy did ) when announcing this stool ( no typo ). 

When I see the grey sheath I'll know the pliers bind up, while my tool in the black sheath performs wonderfully.   

That vid said he's the Product Manager. Does that mean he's the man responsible for these failures?

[Max Stone]

Hopefully his bonus evaporators as their profits are eaten by warranty claims. They can give him the job of responding to all the customer complaints.

And here are their official social media channels, if anyone has the inclination to use these platforms to start a discussion...

https://www.instagram.com/leathermantools/
https://m.facebook.com/Leatherman/
https://mobile.twitter.com/leatherman
https://m.youtube.com/user/LeathermanMedia

[NetsNJ]

Locking taper. Fascinating. I learn something new every day.

[AimlessWanderer]

True locking tapers are typically a lot less than the 30^o shown, but over the years I have found that stuff can have a nasty habit of jamming up when you don't want it to, at or around 30^o. I've had it with cutting tools (taper drills and bore forming tools), taper gibs, self aligning bushings etc. A real pain in the well padded area!

If the void is drilled with an indexable insert U drill, there's a good chance that the face transition is less than 30^o anyway. If they use an indexable insert stepped drill, which would be the most efficient way to drill out the castings, it's likely to have a TPMT insert for the counterbore, set around 15 to 18 degrees. That would fit these symptoms perfectly.

That's what happens when you gear your production facilities around production efficiency, rather than what the component actually needs. Seen it far too often.

[comis]

Well...after 3 days of on-and-off ‘exercise’, including pressing some automotive abrasive into the pivot, I get beautiful free swinging pliers...until I squeeze them, and they bind up again. 

There’s clearly an engineering geometry issue at play here. Not something I’m going to be able to fix, so it’s going back the shop. 

They can send it in for warranty. Hopefully I don’t get it back whacked, but I get one that works.

Have done a video here showing that I need over 500g of pressure to close the pliers when they bind, and that after a wiggle, they are free again. Not acceptable Leatherman. 

No smurf, this sucks!

I had mine right in front me on the table, and just can't help but to give it a firm hand-shake squeeze, and guess what--I just joined the club and now it won't move freely.    Can't imagine what's gonna happen if I give it a real squeeze or need it to cut something.

I gave my old Charge the same squeeze, it binds a little bit but I guessed I have used it enough it frees right up after moving the handles couple of times.(or maybe the handle is heavier?) 


Gave many times harder a squeeze to Victorinox Spirit and Swisstool, until the handles bow inward, no binding whatsoever.

I once said somewhere that this tool is not well thought thru, and only focusing on the aesthetic or appearance, I hate to be right on this.  Even cheaper tools from 20+ years ago can do better.

[Don Pablo]

No smurf, this sucks!

I had mine right in front me on the table, and just can't help but to give it a firm hand-shake squeeze, and guess what--I just joined the club and now it won't move freely.    Can't imagine what's gonna happen if I give it a real squeeze or need it to cut something.

I gave my old Charge the same squeeze, it binds a little bit but I guessed I have used it enough it frees right up after moving the handles couple of times.(or maybe the handle is heavier?) 


Gave many times harder a squeeze to Victorinox Spirit and Swisstool, until the handles bow inward, no binding whatsoever.

I once said somewhere that this tool is not well thought thru, and only focusing on the aesthetic or appearance, I hate to be right on this.  Even cheaper tools from 20+ years ago can do better.

#PSTclub4Life

(Disclaimer: my only LM is a Kick.)

[comis]

True locking tapers are typically a lot less than the 30^o shown, but over the years I have found that stuff can have a nasty habit of jamming up when you don't want it to, at or around 30^o. I've had it with cutting tools (taper drills and bore forming tools), taper gibs, self aligning bushings etc. A real pain in the well padded area!

If the void is drilled with an indexable insert U drill, there's a good chance that the face transition is less than 30^o anyway. If they use an indexable insert stepped drill, which would be the most efficient way to drill out the castings, it's likely to have a TPMT insert for the counterbore, set around 15 to 18 degrees. That would fit these symptoms perfectly.

That's what happens when you gear your production facilities around production efficiency, rather than what the component actually needs. Seen it far too often.

I think every knife/tool maker may eventually come to that point when you get large enough, just a matter of choice between greed vs customer satisfaction.

[Max Stone]

So I returned my P2 to the retail store today as a warranty claim. The Leatherman distributor will collect it next week from the store to action.

Out of interest, I asked the salesman if we could test the P2 and P4 they had in their display cabinet.

Guest what...after a squeeze they both locked up nice a tight. The salesman’s eyes went large and he said he’d show the distributor when he came in.

Seems the problem is not so isolated... 

[SteveC]

This is disgraceful, Leatherman should be ashamed that they let these tools out to the public. Someone must have known about this problem   

[nitram]

My P2 is on it’s way back to the importer. I’ve asked for a Wave as a replacement but they told me that’s not possible. I guess the replacement P2 will be sold unused, I’m done with this.

Makes you wonder, I have an old PST that I’ve used fairly hard for three decades and it still functions fine. Newer isn’t always better.

[Aloha]

I'm not sure what to think  .  If as it seems LM is content to lean on their warranty then this is really unfortunate.  Makes you wonder how many have to come back for them to fix problem and not lean on warranty  . 

 

[nitram]

A fair amount of users will never crank down on them so hard that they’ll bind the pliers, so the number of returns could be limited. Either way, it’s disappointing.

[Poncho65]

  and yep