Too tight

[Edgewise]

Is there any way to safely loosen blades that are held too tightly by the bolsters so that the blades can barely move, commonly called nail breakers?
There isn't even enough room for oil to do the job.
I know that a little light hammering on the bolsters can TIGHTEN a loose blade, but have any of you tried gently prising the inside of the bolster to safely LOOSEN a blade, with a coin or something? Or any other solution for us incompetent handyman amateurs with no workshop to speak of?
Blade walk and talk has been the most prominent, unpredictable, irregular, inconsistent, undependable, unreliable, fickle, meh, bleh, quality control flaw in my knife life.
btw, this isn't a rant........... NOT.

[PCwizard]

I've been lucky loosening a tight blade buy opening it and lightly moving the blade side to side.
I'm not saying to do this, but it worked for me on a few.
Don't over do it, then you will have blade wobble.

[Jeffinn]

I agree with Gary. However, I have a few nail breakers sitting on the shelf and for those knives it’s more about the actual spring tension. If you knife has really strong springs then loosening the fit at the bolster probably won’t help much. But that’s only my opinion and Im sure others will chime in.

[olderdogs1]

You can take a razor blade between the liner and blade and tap lightly. It will loosen the blade but you may have to sand the bolsters even if much loosening is required.

Tom

[orvet]

There are occasions when repairing a knife one does get the blades over tightened. The way I loosen them is to take an old feeler gauge about .015" to .020", then open the blade of the knife to the half stop position and wedge the feeler gauge between the liner and the tang of the blade. Carefully begin to close the blade being sure the feeler gauge is pinched between the liner and the tang, don't let it slip out. Close the blade halfway between the half stop and fully closed, that will exert sideways pressure that helps to loosen the blade. Depending on the knife and how tight it is you may need to close the blade most the way to loosen the blade.

I find it is better to repeat the process several times taking it a little farther in time then to loosen the blade too much.

When I do this in my shop I have various thicknesses of brass strips that I actually use instead of feeler gauges. Most people don't have an assortment of thin brass strips in their toolbox but often they will have flat feeler gauges which is why I suggest that you use those.

[glennbad]

I like Dale's suggestion for bolsters that are too tight. However, I'm still trying to figure out if the bolsters are too tight, or the spring is so strong that it is difficult to open. To me, the bolsters being too tight would cause the knife not have snap at a certain point, meaning the bolsters pinching the tang so it cannot freely travel under spring tension.

If by nailbreaker you mean that the tension is so stiff you'll fold your nail over trying to open it, then that is another issue altogether.

[Edgewise]

It's not the spring because I can feel the drag all the way to open.
Orvet, I have both brass flossing sheets as well as feeler gauges from .0015 to .025 but no way could I insert them between the liner and tang when even the oil gets rubbed away, which goes the same for the razor edge.
And so to PCwizard's suggestion; I inserted the open blade up to the bolster, between my wooden desk top and the heavy glass desk cover, much like in a vice but with still some give, due to the lift of the glass, and I moved the handle up and down slightly but with no result. So I tried again, this time enough to lift the glass a bit and bend the blade slightly.
It may be my imagination but there may be a slight improvement. The blade is quite springy and easily springs back from its bend.(Case SS)
But I'll leave it at that for now and walk the knife a bit more while I grow back some nail. Seriously, my nail chipped in a couple places.
Thanks for all the suggestions. I'll keep you posted on any further developments.

[Dinadan]

Edgewise - I bought a Case Seahorse with the same problem a few years ago. At some point I took a tube of metal polish and just pasted it into the joint while opening and closing the blade. Then I opened and closed the blade a few hundred times, adding more polish along the way. After cleaning the polish out, that actually fixed my knife and it has a perfect walk and talk now. I do feel that for what I paid for a Case it should have been okay out of the box.

If the problem is an overly strong spring and an aggressive corner on the tang, then the only solution I know of is to take a jeweler's file and round the corner on the tang. Not something I would do on an expensive knife, but I have fixed a cheaper knife that way. I have really only encountered that with knives with a half stop.

[orvet]

One method of taking some of the strength out of an overly strong back spring is to remove the rocker pin and replace it with a pin a few thousand smaller.

The undersized pin gives just enough play to remove some of the tension from the springs, thus making the the knife easier to open.

[Edgewise]

I still think the pivot pins are pressing the bolsters and liners too tightly against the tangs because the blades can stay open by themselves every milimeter of the way without snapping. So I'll try Dinadan's metal polish also. It seems the safest way to go (if I have the patience).

[ea42]

Take the knife, open it up, then smack the blade flat on a somewhat forgiving surface, like a mouse pad or leather desk blotter. I don't mean whack it down with all you have, but just with a force kind of like you're swatting at a bug. Hold the knife kind of loosely, not with a closed fist. This works, it's how we slackened knives in the shop all the time that were just a hair too tight. It's possible you may pop the pin a bit, but if you're trying to loosen a blade you likely won't be able to avoid it. Don't over do it or you'll have a loose blade.

Eric

[Edgewise]

ea42, that sounds good because I can increase the smack very gradually until it works.
I'm hoping that too loose can also be corrected by tapping the bolster with a light hammer, although I suppose too much back and forth can loosen the pin's grip.
Are the pins peened over the bolsters at all, or are they just tight enough to prevent movement?

[jerryd6818]

Couple of questions. Am I correct in assuming you mean lay the blade flat on the mouse pad / desk blotter / leather belt / etc (picture #1) and not up on the bolster (picture #2)

And does this work on Schrades using the Swinden system assembly?

And is a wooden mallet / lead mallet / leather mallet preferable over a steel hammer or does it even matter?

[Edgewise]

Couple of questions. Am I correct in assuming you mean lay the blade flat on the mouse pad / desk blotter / leather belt / etc (picture #1) and not up on the bolster (picture #2)
Schrade blade flat.jpg
Schrade bolster.jpg

And does this work on Schrades using the Swinden system assembly?

And is a wooden mallet / lead mallet / leather mallet preferable over a steel hammer or does it even matter?

I thought about it and then concluded that you hold the raised knife by the 'closed' bolster and tap the open blade on the choosen surface, like you're swatting a fly with the blade. Smacking the front of the blade at an angle to the surface will put some sideways pressure on the bolster.
Those who know will answer your second question. MY Schrades don't need adjustment.

[ea42]

Edgewise, yes that's correct. You don't necessarily have to hold the bolster, just the knife handle. An alternate method is to lay the blade flat on the edge of a table, and tap the bolster with a non marring hammer. One or two taps is usually good. You need to use a bit of force, don't be too light or nothing will happen. What you're doing with both methods is to give the pin a bit of a jolt, lightly prying it without using tools to spread the bolsters apart.

Jerry it'll work on swinden construction too, but be careful since what your doing there is pulling on the keyhole rather than the pin.

Eric

[tongueriver]

Great advice from several quarters. Additionally I might say that Kroil or Quick Release squirted in to all crannies, including along the inside of the wells and flexing the blades many times will lube and clean dry springs. Quick Release is a better lubricant overall, but Kroil is possibly just as good for an initial loosening of dry springs. More well-known oils just don't "get in there."

[jerryd6818]

Quick Release is my "first responder" solution. Thanks, I'll give the slap method a try.

[Edgewise]

Quick Release is not available here, as well as many other things you guys recommend regularly.
I'm wondering whether WD40 is a good substitute?
btw, the "slap method" worked great on my knife. I got it just right. Thanks for the tip ea4.