Spyderco Forums

Just got my new zdp stretch. Very comfy knife and everything looks good.

It does have some vertical blade play, it's solid side to side.

I think i read it is normal to have some vertical play on a lock back. Is this true?

I would not say it's "normal", but slight vertical play in midlocks, most often noticeable as a slight "jump" when you press down while cutting, is not uncommon.

I guess normal depends on definition, but all my Spyderco midlocks have it to varying degree. None of them feel insecure with regard to their lock up, but when I'm whittling, or cutting something a bit harder, I notice it immediately.

I guess it's a bit like Chinese water torture: once you've become sensitized, the drops falling on your forehead feel like being hit with a hammer. Same with the diminutive click felt while whittling, impossible not to notice. It doesn't bother me enough to avoid back Iocks, if otherwise like the knife. BTW. I wonder if the new Native 5 and Chaparrals have less blade play? Think it's been mentioned somewhere their locks are made with tighter tolerances.

I think its to do with the inherent, though minute flex that the FRN knives come with. Like Mallus said, I only notice it when whittling in a hammer grip and I ma applying a decent bit of force. For most things its fine nor have I ever had any security concerns with regards to lock failure.

I definantly do not think it should be considered normal on new knives but it is reasonable to get play with use.

It's an inherent quirk of most lockbacks. You can tighten a bit of it out but that does effect the action.

IMHO, the best way to avoid this is to keep the knife very sharp and use more sawing motions. If you have to muscle through something you are going to feel the movement quite a bit more. Then again, in those situations an annoyance still will let you get the job done.

Thanks guys. I'm not concerned about the locks integrity, i just loath blade play in a folder. I know. .. get a fixed blade.

Blerv wrote:It's an inherent quirk of most lockbacks. You can tighten a bit of it out but that does effect the action.

IMHO, the best way to avoid this is to keep the knife very sharp and use more sawing motions. If you have to muscle through something you are going to feel the movement quite a bit more. Then again, in those situations an annoyance still will let you get the job done.

Yes i did notice this. If I tighten down the little torx screw that engages the lock bar i can get rid of a lot of it. The drawback appears that i lose some of "self close" snap you should get as the blade is almost closed.

KevinOubre wrote:I think its to do with the inherent, though minute flex that the FRN knives come with. Like Mallus said, I only notice it when whittling in a hammer grip and I ma applying a decent bit of force. For most things its fine nor have I ever had any security concerns with regards to lock failure.

Except it not only happens on FRN midlocks, it happens on midlocks with both unlined and lined G-10 and Micarta handles, lined CF and GF handles, and all stainless handles.

Mallus wrote:I guess normal depends on definition, but all my Spyderco midlocks have it to varying degree. None of them feel insecure with regard to their lock up, but when I'm whittling, or cutting something a bit harder, I notice it immediately.

I guess it's a bit like Chinese water torture: once you've become sensitized, the drops falling on your forehead feel like being hit with a hammer. Same with the diminutive click felt while whittling, impossible not to notice. It doesn't bother me enough to avoid back Iocks, if otherwise like the knife. BTW. I wonder if the new Native 5 and Chaparrals have less blade play? Think it's been mentioned somewhere their locks are made with tighter tolerances.

While small samples don't really prove anything, I will say that I have four Chaparrals and four Native V's, and none of them have any vertical play whatsoever.

My native 5 is solid. My frn blades have varying degrees of it. Seems the longer the blade the more noticeable it is.

Nope not necessarily, i got a police 3 which has been carried and used a lot and it has a nearly imperceptible lock rock, no click sound while some others developped play and click noise with far less use.
Full stainless handled knives are no exception and they will develop bladeplay.
Also, no amount of tightening will fix vertical play on lock back, when its there, its there...
Having said i never had issue with lock backs while on the other hand i had a lot of liner locks who can flex and slip yet they feel solid lock up wise when you inspect them and put pressure on the spine yet they are really less safe than a lockback with tiny lockrock and clicky sound.
Its all about perception of durability.

My understanding on this issue is how the lockbar meets the notch in the tang when the blade is open and locked. There are a few variations of the back lock. Spyderco came up with one variation they use on the Sage4 and others. I don't know all of them but the Chapparal is one. Here is a picture of my Chaparral CF when I had it disassembled a long time ago. I wish I had a picture of it half assembled so the lock design is more obvious. From this photo notice the groove in each liner around the pivot hole. Also notice the post at the bottom of the blade tang. This post travels in the notch on both sides of the knife when opening and closing. When the post is at the end of the grove it doesn't allow the blade to go any farther when open or closed. You have to picture one liner on top of the blade tang with the pivot holes lined up. Then the post on the tang is visible in the groove in the liner. When open this reduces or eliminates vertical blade play. It's a great design IMO.

Chaparral CF


WAIT! I found a better picture.
Chaparral CF with blade/liners assembled to see the post on the tang in the groove in the liner. As you can see when the blade is open the post hits the end of the groove preventing it from going any farther. With the lockbar holding the blade it won't move in a closing motion. This locks the blade in place better than just the lockbar/tang groove.


Cold Steel has another mod to the back lock that works real well also. I have a mini-Lawman that locks like a tank. Cold Steel makes some pretty good knives IMO but they just don't grab me like Spyderco's do for several reasons. But their Tri-ad back lock works great from what I've seen. I don't recommend you getting one and immediately going out and stabbing your car. :) I'm pretty sure your wife wouldn't walk outside, see the knife in the hood and say "WOW, what a great knife!". :D


Jack