Fasteners

[PeteyTwoPointOne]

The main thing that has attracted me to CRK is the straightforward, solid, and owner serviceable designs. :thumbup:

It's refreshing to have a tool that's so simple and <near> impossible to mess up. I love how all three fasteners on my small 21 will interchange and fit equally well in any configuration.

So, it's a little perplexing to me that the fasteners themselves seem to be very soft metal considering they are integral parts of models intended to be taken down as much as need dictates.

I use Wiha hex wrenches and I'm careful to not misalign the tool when removing the screws or overtighten with "German torque" when re-fastening.

However, it seems, more often than not, I seem to raise a small "burr" on the crown of the screws.

In my few years lurking here and being semi-active in CRK subforum, I read where a few of you guys send in your knives for new fasteners...I've also curiously noted many sales threads mention "new screws" as a selling point.

It sounds nit-picky, but why aren't CRK fasteners more durable? Seems incongruous to me...but, then again, I'm relatively new to the brand and liable to be set straight on the matter...

Would a nice 8 or 10 mm torx be better?

Are there aftermarket fasteners that are recommended by any of you guys?

 

[kidcongo]

You can buy the screws now on the CRK factory web store, so you don't need to mail your knife in.

I've noticed the same thing about the fasteners, but only the male side. The "sleeve-nuts" seem to be harder steel. I wonder, and I'm quite serious here, if the grade or hardness of steel on the male side screw on a 21 wasn't chosen so it catches correctly on the titanium slab to prevent them loosening during carry? A harder grade of steel might not develop the same friction that the milder steel does. It's this friction that makes the 21 so easy to take down.....no loctite etc. Maybe CRK made the choice to have the sleeve-nuts be durable, and sacrifice the male screws in a softer grade for the required 'stiction'.

Just a thought.

Conversely, maybe the softer grade was chosen so it doesn't develop too much friction and stick to the slab so you strip the hex out when you take down the knife after 6 months? Seized screws would suck big-time and I can't recall a single report of that here.

I would say after all these years, the choice is very, very deliberate, but we don't necessarily know the reason. It certainly not the difference between turning a profit and going broke on a $400 dollar knife. There is always more to a Sebenza than meets the eye. Nearly 30 years of development and all.

 

[JNewell]

I would say after all these years, the choice is very, very deliberate, but we don't necessarily know the reason. It certainly not the difference between turning a profit and going broke on a $400 dollar knife. There is always more to a Sebenza than meets the eye. Nearly 30 years of development and all.

Reading comments from time to time over the years here from the Reeves about fasteners, I think the situation is more likely that sourcing these fasteners is maddeningly difficult and, try as hard as they do, the quality varies from time to time. I think the Reeves were and have been deliberate about seeking the best fasteners they could find, but finding sources that meet their standards is tough, and even when they think they've found a reliable and satisfactory source, things change when you don't expect it (like the rest of life...).

 

[JB in SC]

I can't speculate as to the specs of the screws, but they will burr if you're not really careful with the alignment of the bit/ wrench. Off axis just a little equals a burr.

I use the Wiha System 4 interchangeable bit set. I'm not a fan of L shaped wrenches.

The MIP Thorp are excellent, probably the best hex drivers available.

 

[bhyde]

There are no aftermarket choices available except for the clip screw.
They are custom manufactured. I believe the vendor for the male side has changed at least 2x over the years due to centering of the hex and likely other quality issues.
The fasteners are Stainless steel with the female being 303ss. I can't imagine that the male version would be much different in the specification.
Free machining stainless steels are not necessarily hard variants of steel when compared to regular fasteners that you may find on your car or otherwise.Those are hardened to varying degrees depending on the engineering need. Stainless steel fasteners you can buy at your favorite hardware store have the same "soft" characteristics, but may be just a little harder due to the material change from 303ss.

They are custom machined as that is the best way to control dimensional accuracy. The female fasteners or barrels are held to very tight standards. -.0002in IIRC.. The pivot bushing, blade pivot hole and stop sleeve are similar in their requirements. This is part of how the fits come together for form what you have come accustomed to.

 

[Don M]

As JNewell said, sourcing reliable, high quality fasteners has been quite a challenge. I have read comments made by Chris Reeve in the past that this is the case, and that this has been quite a frustration for them. They make some in house now but I don't know to what extent.

 

[PeteyTwoPointOne]

Fascinating....

It would seem when you travel down the rabbit hole of having exacting standards and atom-splitting tolerances, it really exerts a high demand for the same standards to all parts of the system-- even if that system has a bare minimum of parts, such as a small Sebenza.

Now contrast Sebenzas with a communist bloc manufactured AKs or SKS' ... both the Sebenzas & the guns work legendarily with how they are designed .... but you probably couldn't find a more diametrically opposed philosophy of manufacturing.

One demands the highest tolerances to even deploy, while the other thrives on "slop" between components and would probably never even cycle if the components had tolerances of .0002 ... remarkable.

Thanks for all the great information! Forums with knife knuts is the best that social media has to offer, IMHO!

I think I will try using only ball end hex tools to see if that helps.

 

[bhyde]

Fascinating....

It would seem when you travel down the rabbit hole of having exacting standards and atom-splitting tolerances, it really exerts a high demand for the same standards to all parts of the system-- even if that system has a bare minimum of parts, such as a small Sebenza.

Now contrast Sebenzas with a communist bloc manufactured AKs or SKS' ... both the Sebenzas & the guns work legendarily with how they are designed .... but you probably couldn't find a more diametrically opposed philosophy of manufacturing.

One demands the highest tolerances to even deploy, while the other thrives on "slop" between components and would probably never even cycle if the components had tolerances of .0002 ... remarkable.

Thanks for all the great information! Forums with knife knuts is the best that social media has to offer, IMHO!

I think I will try using only ball end hex tools to see if that helps.

That's an interesting juxtaposition..Really makes you think as the things you compared work well and function as designed. Engineering!

On the bolded part- Be careful. I recently broke the ball end off in one of the fasteners trying to loosen it up. Much for the same reason as you, I didn't want to mess up the factory look. It wasn't necessarily a big deal for me to get it out, it did provide a challenge.
In my opinion, the fasteners that you can order directly on Chrisreeve.com, are cheap and available for purchase.. The ball that broke off and wedged would be a pain to deal with and not really worth the expense.
For what it's worth, to explain a little further,. the ball deformed the material just enough to create it's own captive mechanism inside the hex, with the fastener firmly still lodged in the scale.

 

[kidcongo]

There are no aftermarket choices available except for the clip screw.
They are custom manufactured. I believe the vendor for the male side has changed at least 2x over the years due to centering of the hex and likely other quality issues.
The fasteners are Stainless steel with the female being 303ss. I can't imagine that the male version would be much different in the specification.
Free machining stainless steels are not necessarily hard variants of steel when compared to regular fasteners that you may find on your car or otherwise.Those are hardened to varying degrees depending on the engineering need. Stainless steel fasteners you can buy at your favorite hardware store have the same "soft" characteristics, but may be just a little harder due to the material change from 303ss.

They are custom machined as that is the best way to control dimensional accuracy. The female fasteners or barrels are held to very tight standards. -.0002in IIRC.. The pivot bushing, blade pivot hole and stop sleeve are similar in their requirements. This is part of how the fits come together for form what you have come accustomed to.

BHyde.....your post confirms my observation that the male and female side seem to be from different manufacturing processes. You mentioned they are actually from different vendors. Why would this be? Why doesn't the factory making the near-perfect female barrel screws not also just make the male counterpart? Can you think of the reason for two different sources? Are the female barrel screws a standard industrial item that doesn't normally have a male counterpart?

 

[bhyde]

BHyde.....your post confirms my observation that the male and female side seem to be from different manufacturing processes. You mentioned they are actually from different vendors. Why would this be? Why doesn't the factory making the near-perfect female barrel screws not also just make the male counterpart? Can you think of the reason for two different sources? Are the female barrel screws a standard industrial item that doesn't normally have a male counterpart?

Cody-

Years ago, they did use different vendors..I am not sure that's the case anymore. I have probably made 10's of thousands of the female/barrel version at the previous employer. Over the years, there have been a few different people who made them to Chris's standards as an FYI.. I think I know who may do them now, but again, not certain if they do both.
As for the question about making them both in the same shop or vendor..I think it's because;

1) The barrel version could easily be finished, sans hex, on a garden variety, quality CNC lathe. At the time I was involved, it was a Mazak Quickturn 15N.
2) Chris could keep control locally of the parts requiring the tolerances and respond quickly if there was an issue.
3) The male portion requires a more specialized machine to make them cost effective. Screw machines are incredibly accurate and fast, but there were not that many of them locally. The machine vendors likely have a minimum order quantity that dwarfed what Chris had wanted to source at the time..10,000+ I'm sure..where we would make 4,000 or so per order.

Before anyone asks, I'm sure that the growth that CRK experienced was overwhelming to them in the early years. Expenditures on capital equipment was just not in the cards, so local vendors were called on to assist in this growth. I remember walking into CRK from the adjoining shop that I worked at as a 2nd job years ago. CRK was pretty small in comparison to the one I worked in, but no less impressive. It's amazing to see their new shop and of course, the facility that they have just across the street. For sure, I am impressed as well as proud of their accomplishments.

 

[kidcongo]

Thank you for the detailed reply. If you can tolerate a few more questions: Why is it more challenging to put the threads on the outside of a male screw, than the inside of a female barrel screw? Or is the difference the hex head? Did CRK only make the female barrel screws back in the past when they had no hex hole on the dome?

Thanks!

 

[bhyde]

Thank you for the detailed reply. If you can tolerate a few more questions: Why is it more challenging to put the threads on the outside of a male screw, than the inside of a female barrel screw? Or is the difference the hex head? Did CRK only make the female barrel screws back in the past when they had no hex hole on the dome?

Thanks!

I am open to answering questions

The threads are not the challenge in this case Cody. They are relatively easy to make on a CNC..
It's the secondary and tertiary operations on a standard CNC lathe. On the barreled part, the part was turned past the dome portion if you can imagine a line perpendicular to the axis of the part.. it was drilled and threaded at this point, parted off into a parts catcher and then the machine would advance out more material to a stop and repeat this process. At this point, the dome wasn't finished yet. It had to be chucked in a chuck and the dome finished out without squishing the diameter or business end of the barreled part.
On the male part that is threaded, the challenge is, that you have to dome AND broach the hex in the other side. Locating on threads generally isn't a good idea.. If I do locate on threads, it's by having the female end in the spindle and screwing them individually, turn the dome, drill for the broach and then broach. All very time consuming to get all the features concentric. Remember the hexes that didn't seem to be concentric several years ago?
So, the challenge is the hex head.
CRK probably made prototypes and small runs of the barrel screws with no holes.. Like I said, the growth they experienced limited what they did in the shop. Mostly, the small fasteners and turned parts were sourced out (OPK caps). Everything else was in house to my knowledge. With the occasional exception here and there with some scales.

 

[kidcongo]

I am open to answering questions

The threads are not the challenge in this case Cody. They are relatively easy to make on a CNC..
It's the secondary and tertiary operations on a standard CNC lathe. On the barreled part, the part was turned past the dome portion if you can imagine a line perpendicular to the axis of the part.. it was drilled and threaded at this point, parted off into a parts catcher and then the machine would advance out more material to a stop and repeat this process. At this point, the dome wasn't finished yet. It had to be chucked in a chuck and the dome finished out without squishing the diameter or business end of the barreled part.
On the male part that is threaded, the challenge is, that you have to dome AND broach the hex in the other side. Locating on threads generally isn't a good idea.. If I do locate on threads, it's by having the female end in the spindle and screwing them individually, turn the dome, drill for the broach and then broach. All very time consuming to get all the features concentric. Remember the hexes that didn't seem to be concentric several years ago?
So, the challenge is the hex head.
CRK probably made prototypes and small runs of the barrel screws with no holes.. Like I said, the growth they experienced limited what they did in the shop. Mostly, the small fasteners and turned parts were sourced out (OPK caps). Everything else was in house to my knowledge. With the occasional exception here and there with some scales.

aha! makes perfect sense. Thanks

 

[JB in SC]

I recall some years back some issues with the centering of the hex. The newest screws are very nicely done.