Mayo TNT Fit and Finish

[CRH]

I recently received a Buck Mayo TNT from NewGraham and have carried it for a day. I have a couple of issues with the fit and finish and I'm interested in hearing experiences from other owners concerning fit and finish.

1. The blade sits off center favoring the handle slab opposite the lock bar. I can't see that the blade actually rubs on the handle anywhere though.

2. Distal blade grinds are uneven where the grinds approach the thumb hole.

Although these issues are cosmetic and do not acually affect the performance of the knife I find them annoying.

I'm considering sending the knife in to Buck for repair or replacement. What do you think? Am I being too critical of a mass production knife?

Besides these cosmetic issues I just love the TNT. I'm impressed with the overall Mayo design and the Buck TNT may be the perfect EDC gentleman's folder for me.

 

[notos&w]

Naw, not too picky. Send it back. The 172 is a great knife.

 

[Steven Roos]

A frame lock/liner lock often sits towards the non-lock scale when closed due to the pressure of the liner/frame. Try tightening the pivot.

I can't say much on the blade grind other than the fact that they are hand-ground, so there may be more variance than machine ground blades.

 

[CRH]

A frame lock/liner lock often sits towards the non-lock scale when closed due to the pressure of the liner/frame. Try tightening the pivot.

I can't say much on the blade grind other than the fact that they are hand-ground, so there may be more variance than machine ground blades.

This blade offset is probably normal then. I've tried tightening the pivot on both sides but the screws will not tighten. They just turn like they might be stripped.

I didn't know the blades were hand ground.

More comments from owners welcome.

 

[biogon]

I've tried tightening the pivot on both sides but the screws will not tighten. They just turn like they might be stripped.

That's odd...

On my Mayo, it looks like there are screws on both sides, with a pivot assembly in the middle where both screws tap into.

This is a stupid question, but did you hold down one side of the pivot while tightening the other?

-j

 

[CRH]

On my Mayo, it looks like there are screws on both sides, with a pivot assembly in the middle where both screws tap into.

This is a stupid question, but did you hold down one side of the pivot while tightening the other?

No. Is this necessary? I only have one T8 torx.

 

[biogon]

I've seen a couple of knives now where the pivot pin has bolts on both sides, so turning one will make the pin + other bolt turn.

You need to anchor one side and then turn with the other.

One way to determine if it's a loose pivot pin is to hold the knife lock-side up, pull the lock away from the blade (race) and then jiggle the blade itself left and right. Obviously, if you're clumsy, please tape the edge first.

If it jiggles, and especially if it jiggles enough that the washers move, then likely as not the pivot is loose.

Then you can go out to Home Depot or whever and buy a new T8.

-j

 

[CRH]

I've seen a couple of knives now where the pivot pin has bolts on both sides, so turning one will make the pin + other bolt turn.

You need to anchor one side and then turn with the other.

One way to determine if it's a loose pivot pin is to hold the knife lock-side up, pull the lock away from the blade (race) and then jiggle the blade itself left and right.

I have screws on both sides. I found zero blade play with the lock bar disengaged.

 

[biogon]

I have screws on both sides. I found zero blade play with the lock bar disengaged.

Hmmm. Not just disengaged (i.e. unlocked) -- you have to actively pull the lockbar out so that the detent ball doesn't touch the race and keep it pulled away. Lockbar tension on the blade usually is sufficient to give the illusion of no blade play.

BEWARE... you only need to disengage it 0.5mm. If you pull it too far out, you'll really screw up the lockbar tension.

If you're pulling the lock away from the race, and still it has no lateral play... then maybe something else is up and it's an uneven grind. IIRC, there were some that got out of the factory like this -- very uneven grinds, espcially at the tip -- have you tried a search here?

You could also just pick up the extra T8... the other possible complication is that the pivots are probably Locktited so you'll need to break the seal to tighten it (if it's loose from the factory, that is.)

In any case, it would probably be best to send it back. Buck's CS has been very good to me.

-j

 

[CRH]

In any case, it would probably be best to send it back. Buck's CS has been very good to me.

Well I've been carrying and using the 172 every day since I received it - light to medium use, nothing rough. Today I noticed that the blade has moved over and is rubbing on the handle opposite the lock bar. It has developed lateral blade play when tested with the lock bar disengaged. Tomorrow I'll go pick up another T8 and some blue locktite and see if I can fix it. If not it's going back to Buck for service. I certainly trust that they will fix the problem if need be.

Thanks for your advice biogon.

 

[biogon]

That sounds very much like a pivot tension problem.

I'm sure I don't need to tell you this, but likely as not you'll probably need to be very precise with the drivers to have a balance between an overly stiff action and blade play. This is especially true with framelocks, as the lockbar pressure can be very high compared to a linerlock.

Sometimes the sweet spot is less than 1/4 mm of arc... especially if they used bronze washers. If they're teflon or nylatron, you have a bit more space to work with.

Good luck!

-jon

Well I've been carrying and using the 172 every day since I received it - light to medium use, nothing rough. Today I noticed that the blade has moved over and is rubbing on the handle opposite the lock bar. It has developed lateral blade play when tested with the lock bar disengaged. Tomorrow I'll go pick up another T8 and some blue locktite and see if I can fix it. If not it's going back to Buck for service. I certainly trust that they will fix the problem if need be.

Thanks for your advice biogon.

 

[CRH]

That sounds very much like a pivot tension problem.

I'm sure I don't need to tell you this, but likely as not you'll probably need to be very precise with the drivers to have a balance between an overly stiff action and blade play. This is especially true with framelocks, as the lockbar pressure can be very high compared to a linerlock.

Sometimes the sweet spot is less than 1/4 mm of arc... especially if they used bronze washers. If they're teflon or nylatron, you have a bit more space to work with.

Just a little bit of tightening was all it needed. No blade play now and no rubbing on the handle. I did a little experimentation and found that tightening the pivot beyond resonable force to open it does not have any effect on parked blade position as biogon predicted.

I didn't take the thing apart to see what kind of washers it has. Is this variable with the 172?

 

[biogon]

Sweet -- sounds like you fixed the problem, then. It's a common problem with folders IMHO.

You might consider wrapping the pivot a couple of times with teflon tape (pipe tape) to prevent it from coming loose again. Some people use red locktite, but it can gum up and I prefer to be able to easily disassemble and reassemble my knives, so it's teflon tape for me.

I have no idea, unfortunately, as to what washers are used in the 172.

The Buck Strider series uses bronze phosphor... Mayo customs use teflon.

If you shine a flashlight into the pivot, you can usually tell by looking. White, fat, smushy ones are teflon, grey ones are nylatron, and bronze ones are... bronze.

-j