My new Buck 112 is too stiff

V

Valle

Joined
Apr 8, 2006
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130
Hi everybody. I bought a Buck 112 online and, as aways, I asked the vendor to check for blade play before sending it to me. He followed my instructions to the letter, and I received a knife that locks up like a vault. The problem is, the knife opens very smoothly until about 60 degrees, then it gets gritty and stiff until it is completely open. So far, I have done this:

1. Washed it thoroughly with hot water and scrubbed the pivot area with a toothbrush.
2. Dropped a few drops of oil in the pivot and worked it, repeatedly opening and closing the knife. I did this a lot, and removed most of the remaining gunk.
3. Left the knife half open at various positions during the nights, to see if the backspring would give up a little bit.

I must say the grittiness has all but gone away, but it is still abnormally stiff to open. It seems the bolsters are just too tight. It is perfect in every other way, I won´t send the knife back to Buck, but I must solve this problem myself. Is there anything else I should try? Any advice?

teste2_zps0wovzk02.jpg
 
Try wiggling the blade back and forth, and see if the lateral pressure will open it up a little
 
Here is what to do: go buy some old fashioned white toothpaste (not gel). It is a very mild abrasive and is water soluble. Put a generous amount into the pivot/bolster area and open and close the blade a hundred times or more, adding toothpaste as needed. Then, flush it out with hot water, re-oil it well, and your problem will be mostly solved. The more you use the knife the better it will get, in any case.
Or, you could send it to Buck to fix.
My way is faster and works well.
 
Well, there's no way for you to tell us or describe how stiff is stiff, but —

You don't mention what oil you're using, but 3-in-1 would be a bad choice, as it's awfully thick for such applications. I recommend using some penetrating oil (like Liquid Wrench) to see if that loosens more of the grit in the joint and washes it out. Be generous with it.

If it does clean out the grit, then wash with soap again, dry, and all that. Then apply a good gun oil like Quick Release or Break Free. These will penetrate nicely and leave a film on the metal which will keep it moving smoothly.

If that doesn't work to your satisfaction, send 'er back to Buck.
 
rinse it out with wd 40 or something to clean it out. Then use it, as in work it back and forth.
 
RBB, I am using Militec.

DocT, I will try it with the toothpaste.

In any case, soon I will back to tell the results.
 
The toothpaste will work. Old timers remedy. It is a mild abrasive. You can go to ACE or somewhere and buy some very mild abrasive and spend more money, but this will work and is water soluble. Remember, no gel. White paste only. When you finish the knife will be slick to open and close.
 
I don't offer a solution to your problem however what is the fixed blade in your picture?
 
Except for the grit part it sounds like my 500. I just keep it oiled some and using it; seems to be breaking in! My 500 has got a tank of a lock up on it!
 
Peter Parker, I used to have a Buck 110, one of the new ones, and it wasn´t nearly as stiff as this one. The grit has gone away, but is still uncomfortably stiff, as if the bolsters were too tight.

Doc, as chance would have it, my local shop only carries gel toothpastes. I will buy the white one elsewhere.

155440, it is a 1070 knife a firend gave to me. He made it.
 
Valle said:
...the knife opens very smoothly until about 60 degrees ... but it is still abnormally stiff to open. It seems the bolsters are just too tight.
Click to expand...

Tight bolsters should pinch the blade regardless of the angle that it's open, no?

Easy test to rule out the spring/tang intersection: hold-down the lock-release lever so that the lock-bar doesn't contact the tang at all, then try rotating the blade. If the blade does not rotate all the way from closed to open and back with relative ease, the pivot is too tight and needs service. If the rotation is gritty, pivot needs cleaning (as already suggested). If the blade DOES rotate easily when the lock-bar is fully disengaged, the issue is the strength of the spring or the shape of the tang.

The curving shape of the tang as it rotates against the lock-bar pushes the bar up against the pressure from the back-spring (just like a slip-joint). Normally the tang is nice and circular, equidistant around the pivot except in the cleft where the lock-bar engages when open (tang spine) and on the flat of the face where the lock-bar tension keeps the blade closed. Maximum tension should be achieved at the corner of the tang where the flat face transitions into the curve (pretty close to 60 degrees on a lot of lock-backs) and maintained along the curve until the lock-bar snaps into the cleft. A poorly-shaped tang or overly-strong spring would make opening around that curve challenging (I have an Aitor that is dangerously difficult). The spring should break-in over time, but no amount of cleaning will change the shape of the tang.
Or it might be the bolsters?
 
I've gotta ask, is it so stiff that you can't open it?

Do you have other 112's or 110's to compare it to?

Do you want it loose enough to where you can grip the blade and wrist drop it open?

110's and 112's will last you and your kids a lifetime.
A little stiff is better in the long run.

Unless you do want to be able to pinch and drop it open one handed.

Just curious..
 
Take a large flat tip screwdriver, pad it and insert it between the bolsters on the well side of the knife and tweak it very gently (kinda wobble it a bit). That should lighten the pull of the blade. Oil the joints and use it.
 
DocT, I regret to say the white toothbrush did nothing to improve the situation. I smeared a fair amount of it in the pivot area and worked it opening and closing the knife for an hour. The stiffness did not improve at all. I will take another picture and post it, perhaps I could try something else. I won´t be sending this knife back to Buck, I am sure you understand.

Chiral.grolim, I have just done your test. When the blade is getting opened downwards of 60 degrees, it gets stiff to open or close, even with the lock-bar firmly and fully pressed. I agree that tight bolsters should pinch the blade regardless of the angle it's open, but that is not what is happening with this knife. It starts opening lightly and smoothly, and suddenly it gets stiff. I will take anoher picture to illustrate what I mean.

Pack Rat, the picture in the first post is an actual picture of the knife. It is very unlike a new Buck 110 I had (post 13 in this thread). This new 112 is impossible to open one handed. I want to be able to open it one-handed, yes.

Modoc, have you tried this method before? Should it not cause more problems? Keep in mind it is already very light and easy to start opening the knife .
 
Another picture.

buck_zpst8lrf97d.jpg


The knife opens easily and smoothly until that point. From there onwards it gets stiff to the point of it being a hassle to open with dirty hands. Lockup is very tight and solid. When the knife is open, the lockbar touches the tang fully and smoothly. No bladeplay whatsoever in any direction.

I must say I need to be able to open it one handed, like I did with all Buck 110s I ever had.
 
After an hour it should have smoothed up some. It does not sound like the bolsters or the lock bar. There may be an issue with the pivot. I had a Boker that literally froze up on me even though I had oiled it. I sent it in and there was an issue with the washers or something (long time ago) so they had to take the knife apart, relube it, then put it back together. I would send it to Buck and let them fix it for you.
 
I had a similar problem with a 532 that I bought second hand at a show.
I cleaned and scrubbed it to no avail.
finally I gave up and sent it in to Buck.
They repaired it buffed it up and sent it back no charge and postage paid.
the paperwork said it had a broken spring.
 
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