The ZT no one is talking about! ZT0804CF

[RamZar]

I love the 804cf.. I am not crazy about the DLC coated blade, but my main issue the cost. I think it is 80-100$ over priced.

It'd be about $60-$80 less if they used titanium instead of CF, steel instead of titanium clip, S35VN instead of 204P and no DLC. So, it's priced right.

 

[Tachead7075]

HI Tachhead -

None of the pictures you show provide anything but reinforcement of the point that the bearings do not "wear into" the titanium, but there will be witness marks on the ti where the balls do run, that is perfectly normal.

I have never seen or heard of one instance on any knife where the balls of a raced bearing put a groove into the Ti to the point where the race made contact.

IF you had that happen I would like to see the result, as that would not be good.

However, your assertion that a small washer would somehow resolve the problem, or the perceived problem, is valid; it would not cost much to provide the extra washer.

That must mean that the experts that make the knives, that know metallurgy and have professional expertise in this field don't believe it necessary, and I doubt it was a dollar cost decision, if you see my point.

I wonder if one could order a thin washer from alpha to insert into the bearing pocket if one were bothered by the design? It could not cost more than a buck or two.

best

mqqn

In the video their is metal filings in the bearing and races. Where do you think that came from? And, while not the best pics(and who knows how much use these examples have), you can clearly see where the bearings have wore a groove into the titanium. It is more then the witness mark that are on the blade side. and, keep in mind that the blade will still see some wear too, although no where near the amount the ti does, because it is softer then the hardened ball bearings as well.

Of course you havent. ZT uses polymer bearing carriers which will not provide witness marks like metal ones do and will also provide the same smooth pivot that a polymer washer will if the wear ever gets that far.

It may not be a huge problem but, it is one none the less and is not a good engineering decision. There is no reason really not to use a washer other then cost/price point. Remember most companies arent out to make the best longest lasting product they can, they are out to make money and are happy as long as the reliability is good enough to keep warranty claims to a minimum.

 

[stabman]

It may not be a huge problem but, it is one none the less and is not a good engineering decision.

Are you an engineer?
I know a few of them, and they like how the ZT's are made...I guess it must be a good engineering decision then.
Engineer approved. :thumbup:

 

[Tachead7075]

Are you an engineer?
I know a few of them, and they like how the ZT's are made...I guess it must be a good engineering decision then.
Engineer approved. :thumbup:

I took an Aerospace Manufacturing course in college and have many years of mechanical experience. I have changed, installed, and worked with thousands of bearings of many different types in many different applications. And, I have 2 different friends with different engineering degrees(one mechanical).

I like ZT. I generally like their designs, engineering, and fit and finish too. But, this particular part of their titanium scaled models is not the best design.

 

[stabman]

I like ZT. I generally like their designs, engineering, and fit and finish too. But, this particular part of their titanium scaled models is not the best design.

Oh well.
While others obsess over best design solutions to problems that really aren't problems, I'll just continue using my knives.

 

[Tachead7075]

This is not really the place to argue about this nor is it really even an argument that the design wouldnt be better with hardened washers(I am sure almost any mechanic or engineer would agree). Lets get back on this threads topic, we can start a new thread to discuss this more if needed.

 

[stabman]

This is not really the place to argue about this nor is it really even an argument that the design wouldnt be better with hardened washers(I am sure almost any mechanic or engineer would agree). Lets get back on this threads topic, we can start a new thread to discuss this more if needed.

Sure it's the place for it.
And if you put steel washers into it, some weight obsessed weenie would complain that it weighed 1 gram more than was optimal...just look at how the titanium scale in the video you provided was all milled out.
Mine is not milled out (thank God), because ZT decided the minimal weight savings wasn't worth the hassle, but they knew that there are folks out there who obsess over the tiniest details like that.

As to the original topic, I don't talk about the ZT 0804CF for the simple reason that I don't own one.
I cannot really talk intelligently about a knife that I do not own.

 

[Tachead7075]

Oh well.
While others obsess over best design solutions to problems that really aren't problems, I'll just continue using my knives.

You say this is not a problem but, for me, it is a simple design feature that easily could be made more durable for very little increase in cost and production time. Even if the wear is only minimal over a couple of years of infrequent use, how about in 20 or 30 years of hard dirty EDC use? With a simple very thin hardened steel washer it would greatly increase wear resistance, so why not do it? Especially on an open bearing design that is prone to debris incursion in effect turning the bearing oil/grease into an abrasive compound similar to lapping compound. If I designed these knives I would put a very thin hardened steel washer on both sides of the bearing so there was no wear on the blade either as it is quite a bit softer then the bearings as well. This would prevent any wear to the scales and blade and allow you to just swap out the washers and bearing to completely refurbish the pivot.

You have to understand that most companies arent very concerned with making a knife, or anything for that matter, as durable and long lasting as possible. Making products or parts that wear out keeps you buying more. That's part of the reason we have transitioned into a "disposable society". Making things that dont last helps fuel and maintain the economy. But, that is another topic lol.

I for one would rather have a proven design(one piece bearings have used hardened steel races for years for a reason) and one that doesnt show wear so quickly. Especially when spending hundreds of dollars on a high end knife. I buy knives for life and expect them to last a lifetime or at least as long as possible. So, I am not a big fan of this bearing design. I hope ZT takes note of other manufactures and also adopts the protective washer design in their Ti scaled knives. It may not bother some other people but, with my mechanical knowledge and experience it does bother me and often prevents me from wanting to get certain models of ZT knives. Which is a shame because they have some sweet designs imo and I like their brand quite a bit.

 

[Tachead7075]

Sure it's the place for it.
And if you put steel washers into it, some weight obsessed weenie would complain that it weighed 1 gram more than was optimal...just look at how the titanium scale in the video you provided was all milled out.
Mine is not milled out (thank God), because ZT decided the minimal weight savings wasn't worth the hassle, but they knew that there are folks out there who obsess over the tiniest details like that.

As to the original topic, I don't talk about the ZT 0804CF for the simple reason that I don't own one.
I cannot really talk intelligently about a knife that I do not own.

Yep, somebody is always going to find something to complain about and I am sorry it is me this time:redface:

But, constructive criticism can help bring things to light for people/manufactures and can help designs improve going forward so, I for one think its a good thing. YMMV.

 

[stabman]

Yep, somebody is always going to find something to complain about and I am sorry it is me this time:redface:

But, constructive criticism can help bring things to light for people/manufactures and can help designs improve going forward so, I for one think its a good thing. YMMV.

If they put steel washers in there, I wouldn't complain about it.
It really wouldn't add anything in the way of cost...those washers are cheap.

I guess we'll see in 500 years if my ZT without washers wears out before my shiny new cyborg body.

And don't feel bad about complaining about features that I or others don't think are a big deal; if no one pointed out things they didn't like, this forum would get really boring.

"I like everything about my ZT knife."
"Me too!"
(and then the thread dies off)

 

[Rival1314]

This is not really the place to argue about this nor is it really even an argument that the design wouldnt be better with hardened washers(I am sure almost any mechanic or engineer would agree). Lets get back on this threads topic, we can start a new thread to discuss this more if needed.

you seem to have a very strong opinion on this matter, do you have any actual first hand experience with it happening?? I can tell you first hand I have taken apart over a hundred ZTs over the past several years in the process of upgrading and modifying knives....not once have I come across any issues where a channel was worn into the Ti....You seem to be over thinking the issue.

Would having a steel insert be nice? sure.
Would it improve the design? in my opinion, no.
Does it cause any issues for use, or weaken the integrity of the knife? no

If the knife/design isn't your cup of tea that's one thing....but done exaggerate an issue that doesn't exist. ZT has made tens of thousands of knives with this same setup....if they saw an increase in wear or warranty issues I assume they would update the design to minimize repair costs. The fact that has not happened indicates to me that it is a matter of preference, not performance....and definitely not a design flaw.

Welcome to the forum, its a perfect place for a healthy discussion....

 

[sharp_edge]

Tachead - what you said seems theoretically interesting. However, as you claimed you are familiar with engineering, could you please make you claim regarding the engineering flaw of ZT in a more scientific way? For example, how many times of the bearings balls running on the Ti track will result in a channel of how many mm deep? Rather than vaguely sating 20-30 years of hard use etc.

 

[Rasco]

For what it's worth, I've never really liked the Rexford designed ZTs.
Love all the others, particularly the Sinkevitch & Hinderer designs, But the Rexford's just never spoke to me

 

[Tachead7075]

you seem to have a very strong opinion on this matter, do you have any actual first hand experience with it happening?? I can tell you first hand I have taken apart over a hundred ZTs over the past several years in the process of upgrading and modifying knives....not once have I come across any issues where a channel was worn into the Ti....You are over thinking the issue.

Would having a steel insert be nice? sure.
Would it improve the design? in my opinion, no.
Does it cause any issues for use, or weaken the integrity of the knife? no

If the knife/design isn't your cup of tea that's one thing....but done exaggerate an issue that doesn't exist. ZT has made tens of thousands of knives with this same setup....if they saw an increase in wear or warranty issues I assume they would update the design to minimize repair costs. The fact that has not happened indicates to me that it is a matter of preference, not performance....and definitely not a "design flaw".

Welcome to the forum....take advantage of the knowledge and experience here

Yes, I have first hand experience with this bearing race wear. The wear in the Ti pocket compared to the wear in the blade pocket was more and it should be because the Ti is much softer then the blade steel(both are much softer then the ball bearings). The second pic I posted(not my knife) clearly showed more wear to the scales(more then just witness marks). As did the video and the poster even said there was metal filings/dust.

Click to magnify it and see for yourself.

http://i.imgur.com/7i3ieZh.jpg

Keep in mind too that very few people hard use their ZT's(although some do) because they are expensive, cosmetically attractive(imo) and often used more as man jewelry. Many people just flick them on the couch, open packages, cut food with them exc. which really doesnt put much use on the knives and they are mainly in a clean environment keeping the bearings fairly clean. Also, people on this site, for instance, likely have many knives, rotate through them, and know how to maintain them as well as want to because they are knife enthusiasts. These knives and ZT as a company are also fairly young with only a handful of years of light use on them at most. I bet with many years of hard EDC use(what many ZT models are designed for) by a normal person(not a knife enthusiast) this wear will be greatly increased. Especially because they may carry the same knife every day, possibly in harsh environments(a tradesman, outdoorsman, exc.), and never clean or lubricate the bearings.

I dont see how you think adding hardened steel washers wouldnt improve the design but hey, everyone is entitled to their opinion and I respect that.

Anyway, I think this topic has been discussed enough and I only brought it up as constructive criticism. I still like ZT and think they have some great designs. I just would like to see them adopt this design like other manufactures like Spyderco have. YMMV.

 

[Tachead7075]

Tachead - what you said seems theoretically interesting. However, as you claimed you are familiar with engineering, could you please make you claim regarding the engineering flaw of ZT in a more scientific way? For example, how many times of the bearings balls running on the Ti track will result in a channel of how many mm deep? Rather than vaguely sating 20-30 years of hard use etc.

I'm no engineer but, I do have some experience and training.

That would be vary hard to do/say as it would depend on many variables including titanium scale hardness(HRC), ball bearing hardness(HRC), pivot tension, the kind of lubrication used, the operating environment, the bearing cleaning interval, exc.

Even if the design did use hardened steel washers there would still be wear. It would just greatly decrease the wear. What I can say is regular cleaning and use of a good synthetic lubricant will extend the life and minimize wear no matter what material is used. Open bearings(without seals) quickly become contaminated with debris which acts as an abrasive and the cleaner you can keep the bearing, race, and its lubricant, the longer it will last. This is why sealed bearings are used in many(most) applications. They offer much longer service lives without any maintenance.

Edit: added more info

 

[Tachead7075]

For what it's worth, I've never really liked the Rexford designed ZTs.
Love all the others, particularly the Sinkevitch & Hinderer designs, But the Rexford's just never spoke to me

Me neither and I prefer the other designers stuff too. But, I have to say I like this one. Its got a nice shape and many nice features imo. I like the almost ffg blade and d-shaped captured pivot bolt(more ZT's should have these imo). Throw some hardened steel washers(sorry), a standard PVD/TiN/TiCN black coated clip, and a satin or stonewashed bare blade and I would by one.

 

[AusLoX]

I really like the blade shape. Almost like a smoothed out tanto. Very long up sweep to it. Great steel choice, I prefer it over s35vn. It feels great in hand and flips great. Not a big fan of the pocket clip as far as function goes, but it looks cool.

 

[whitty]

1st off to Tachead7075 I do not consider your posts a hi jack/off topic post at all. I appreciate everyone's thoughts and opinions. I have even gone as far as to copy a couple of them and email them to ZT to see what they can tell me back about this. I will post it back here when I get a response.

2nd I am actually shocked at some of the owners of the 804CF that like the knife but are not huge fans of the clip. I guess they are not the same ones who keep saying they want to see a ZT with a harder core clip. Not sure why but it just surprises me!

 

[Insipid Moniker]

1st off to Tachead7075 I do not consider your posts a hi jack/off topic post at all. I appreciate everyone's thoughts and opinions. I have even gone as far as to copy a couple of them and email them to ZT to see what they can tell me back about this. I will post it back here when I get a response.

2nd I am actually shocked at some of the owners of the 804CF that like the knife but are not huge fans of the clip. I guess they are not the same ones who keep saying they want to see a ZT with a harder core clip. Not sure why but it just surprises me!

I'll be honest, I think 99.9% of machined clips are a purely aesthetic touch that sacrifices utility for good looks. I'm sincerely hoping they're a fad that doesn't spread any farther. I want spring in my clip to accommodate a variety of material thicknesses and allow some personal adjustment on my part. Heck, my hands-down favorite pocket clip remains the G&G Hawk Grip Clip as it holds securely no matter what and adjusts to whatever thickness of material no matter what. Machined clips I find to be the complete opposite.

 

[whitty]

I'll be honest, I think 99.9% of machined clips are a purely aesthetic touch that sacrifices utility for good looks. I'm sincerely hoping they're a fad that doesn't spread any farther. I want spring in my clip to accommodate a variety of material thicknesses and allow some personal adjustment on my part. Heck, my hands-down favorite pocket clip remains the G&G Hawk Grip Clip as it holds securely no matter what and adjusts to whatever thickness of material no matter what. Machined clips I find to be the complete opposite.

You are not freaking kidding. I would love to see the G&G clip become standard on all knives. Love it!