Anyone else with ZT0801 having problems with the pivot ?

victorf said:
The underlining problem with 0801 and the likes is with the thrust bearing on the pivot lacking proper support. Titanium liner sides has no harden washers, the inner thrust bearing does rotates on the harden knife tang.

Thrust bearing needs hardened ground flat washers on both side to support the harden middle balls. Proper functionality is adjust to achieve very little clearance/play for intended design. Hardened balls will wear into the soft titanium with multiple flipping.

Blue Loctite will not cured the excessive clearance caused by the one sided thrust bearing wear into the titanium.
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This is pretty much hog wash. Titanium work hardens. It would take an insane amount of time for this to happen if it happened at all.

Until someone shows me a bearing pocket with a groove worn in it, there is no way I am believing this.
 
Not so sure why that's so hard to believe, over a bit of time of course. The steel tang wears out ti lock faces doesn't it? All the more reason for caged bearings.
 
crom said:
Not so sure why that's so hard to believe, over a bit of time of course. The steel tang wears out ti lock faces doesn't it? All the more reason for caged bearings.
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Yes, but that's because of galling. There is no galling between the bearing and the frame.
 
The bearings that are used in the washers are of a fairly soft steel, and they roll over the surface of hardened titanium. victorf assumes a premise that is doubtful at best.

Until there is actual evidence of anything, why assume an issue?
 
Suffice to say, that I did have a little first hand experience working with various alloys and their variants after 39 years as a Nuclear Qualified ToolMaker in the Nuclear Industry. That aside....

My Benchmade AFCK titanium liner lock EDC for 13 years, used only on cutting fruits for lunch(I respect tools, that is how I used my EDC), before I retired. Blade is made of ATS-34, stayed razor sharp, never sharpen in the 13 years. Out of sentimental reason, recently gave it an mirror polish edge on my WEP before retiring it among my collections. Liner lock engagement when new was 25% in 1996, now at retirement it is > 60%. Liner lock is sticky to say the least.

Among other favorite alloys, I do like working with Titanium, made custom parts to lighten, when I was building my 18 lbs. Guerciotti road bike, back in 1983. My current pocket rocket 1000cc motorcycle has titanium headers, axles and....

Among others, this is what I made recently for my "other" toy:

DSCN1878_zps1bce36e4.jpg


Titanium has many great attributes. But using titanium directly as an race washer for thrust bearing or directly against the harden tang of a knife, not so much as my preference. Softer titanium (work harden property) not with standing, repeated contact with heat treated steel, it will always ended up as an sacrificial element and resulted with uncontrolled clearance among associated components.

Hint: Take a look on the Sypderco Domino, it employs outer harden washers on the pivot thrust bearing and stainless insert on the titanium frame lock. I do appreciate precision tools. That is one of my favorites while watching TV or while reading forum postings. It screams flip me and I frequently do for shear pleasure. Thousands of flips later and it is fresh like the day when I first flipped it. To me, if Domino gotten smoother or looser after thousands of repeated flips, needs periodic adjustments, I interpret that as components gave in to wear. Pretty good, I suppose, my Domino never got better. I am happy with that.

I don't know much, I can speak only based on what I know. Sorry if it sounded like hog wash!
 
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Mine loosens up, but I haven't gotten around to adding Loctite yet (doing it is no big deal to me, it's just part of normal knife maintenance) because I figure that I will eventually do some modding (blue Ti standoffs, maybe?). I just need to quit being lazy and break out the Loctite, lol!
 
I have not had any problems with either of my 801's, and locktite has worked fine for my 560's as well - I did have a pivot loosening on my 560, and a single drop of loctite blue, and letting it cure for a day resolved that issue.

I don't dispute that bearings running on any kind of race will wear, but we are talking a very low load surface here, and the wear would be thousanths of an inch over years of service, and the pivot allows for adjustment.

Does not seem like headline news, and not likely the problem with any of the 801's that are in service today - they just have not been around long enough to have worn a groove in the ti - just my opinion on that, no empirical evidence of course outside of my knives.

Victor - nice shift knob - you making those for vettes? I have a billiard ball style on my Z06, but would love a round Ti ball - Calloway had one at Bloomington Gold one year, I did not buy it but always wanted one....

Would the threads on the inside of the knob wear against the steel threads of the shifter actuator lever with repeated shifting, especially at the drag strip? My billiard ball knob has a steel insert.

best

mqqn
 
Victor, I think your ATCF is proof its much ado about nothing. 13 years and the lock still hasn't made its way across the tang and that's far more stressful than the bearings. Imagine if someone told you that your atcf wouldnt last because its needs a hardened steel lock face, what would you say?

If the bearings were under intense pressure, I would agree that it would wear a groove but there isn't much pressure on the bearings.

How about this? Let's get a scrap piece of 6al4v and a set of kvt bearings from KAI. Let's chock the bearing race into a screw gun and run it against the titanium for 20 minutes under just the weight of the screw gun. That should easily be a lifetimes worth of wear and see what happens.
 
Andy,

If there is clearance or lack of a better word, slop fit, between Ti and stainless shifter shaft(In my case, an MGW), clearance due to play will induce wear phenomenon. Some makers prefer using steel or synthetic insert, that also provide height adjustment along with an jam nut. I make mine, that is a good thing because I can directly control the required precision fit as well as custom fitted height by using an internal machined delrin bearing spacer and along with bypassing the complexity of an insert/jam nut.

I made several knobs with various material, T6 (light, soft but scratch easily, also don't like the warmth-its an excellent conductor from tunnel heat). 304 cres was nice. Delrin or G10 was ok. Exotic wood, beautiful but requires metal insert adapter, so its too bulky. Out of all, Ti is my favorite, poor conductor of heat and I like the rainbow effect from controlled high heat exposure after extensive mirror polishing - sort of an halo effect.

Back to the subject of knife. I am trolling forums and sites, waiting for Zt, CRK and the likes to produce the future knife I am waiting with the attributes and more such as some of those, incorporated on the Domino. Enabling me to flip without restrain, its a toy for me no less. I do like the 0801CF, CRK and others but I am holding back due to my expressed opinions.

Sorry folks for the Hijack! Aloha.
 
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My 0801 is fine, but my 0770CF definitely needs some loctite. picking some up tonight.
 
Sounds like you need a zt0777 victor. It has the washers because of the full carbon frame.
 
Anyway as an update, I opened my pivot up, blue loctite-ed it and it seems fine now.
 
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