What exactly is the definition of blade play?

The General

The General

Joined
Jun 6, 2000
Messages
3,625
Yes I know lateral and vertical movement...

BUT on some of my knives (Sebi, 710 and LCC) when I grip the knife hard and try to bend the blade back and forth I get no movement at all, just like a fixed blade. With other knives I get about 1-2mm of movement side to side. Is this what is refered to as blade play? Or is blade play a bit more significant than this? I swapped my AFCK with Nemo a little while ago. It is now his daily carry! Well I thought it DID have blade play. However he said it did not! So it got me thinking what is the recognised value for blade play. At what point does it really become blade play?
I noticed my MOD CQD has about 2mm play lateraly, yet I am told it ought to be rock solid. This is ONLY when I hold it very tight and rock the blade left and right. Is this normal for most knives? I am playing with my BM 750 right now and it is ROCK solid.
Cheers!

W.A.

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Am very interested in the answer(s) to this. I haven't checked the only two folders I have that aren't CRKTs. But, have checked all my CRKTs multiple times, and only on occasions where my finger wimps out on me and my M16-14 barely opens have I had any movement in any direction on any of them. Can I ask if blade play is related in any way to quality?
rolleyes.gif


Bugs
 
Blade play, what Gollnick does with a Balisong! (Check the link in his sig sometime, I did last night and it's pretty cool!)
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Seriously,

All folders will have some amount of lateral movement in them, this is acceptable. However, to me vertical movement is not. Lock up should be VERY solid, if not, it's not locked.

Something like 15 years ago, a very knowledgable knife and sword maker, (small time, you haven't heard of him) told me that the way to test for blade play was to grip the blade approxmiately 1 inch forward of the pivot and gently wriggle the blade back and forth. Grabbing near the tip and doing this is basically using the blade itself as a prybar and actually causing blade play.

Now, a caveat, Lockbacks have less bladeplay than linerlocks. (or similar.) Why? A linerlock's blade is not held tight by the liners. There is always some sort of bushing arrangement that prevents the blade itself from contacting the liners, thus causing slightly more lateral play. Lockbacks, with solid bolsters contact the blade over a much greater surface area, and there is no "give" as there is with a liner lock. Does this mean a lockback is more secure than a linerlock? Apples and oranges, you can't really compare the two.

It's a matter of personal preference but to me, I'd say 1/8th inch lateral play (observed at the tip) in a linerlock is perfectly acceptable. In a Lockback, I'd say it was marginal.
The above is IMHO, YMMV etc, but I'd say if the knife "feels" secure to you, then don't worry about it. If it feels loose, contact the manufacturer about having it tightened up.


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Tráceme no sin la razón, envoltura mi no sin honor
Usual Suspect
 
General: I view blade play as any perceptible movement of the blade. When this occurs, I back out the pivot screw, clean the threads and use a bit of blue Lok-Tite and tighten to an acceptable level. In time, I think this will happen with just about any folder.

P.S. Watch for comments on the ECCK Show in NYC starting tomorrow.

Dick
 
If you grip tightly enough just about any blade will "move." I view "play" as the ability to "ROCK" the blade. Almost as if it will move to a point off center and THEN stop. As someone earlier said you can use the blade as a prybar against the handle and force it to move. BUT it may have no EASILY created side-to-side movement.
 
Thanks! I am not OVERLY concerned over the lateral movement in my blades. I was interested though, that there does not seem to be a codified description of what blade play is and is not. It seems to be down to individual opinion, rather than yes it has or no it does not. I figured on a liner lock a little blade play was par for the course as well as on zytel and FRN blades. I was a little interested that my MOD knife has a bit of what I would call blade play. Then again my BM 855 had more than a little and I had to tighten the pivot quite tight, making the knife rather ungainly to open now...

Ah well, such is the curse of being a KnifeKnut!

W.A.

------------------
"To strive to seek to find and not to yield"
Tennyson
Ranger motto

A few useful details on UK laws and some nice reviews!
http://members.aol.com/knivesuk/
Certified steel snob!
Founding president and member number 1! Wana join?
 
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