Do flippers need ball bearings for a top notch action?

[Lord_Balkan]

So I've been thinking about this. I have many super smooth knives on washers. A lot of them can be drop shut smooth when the tolerances are right. A good benchmade, a sebenza with polished washers, etc. From what I've seen, it seems like the bottleneck for smoothness is when the detent ball rides on the blade, and not the smoothness / friction on the actual pivot. My Sebenza are completely free when the detent ball is not on the blade, and a good 940 Benchmade can swing freely.

I may not be understanding the whole picture here, so I apologize in advance. Feel free to educate me. But if I understand this correctly, why do flippers need ball bearings? Couldn't you get a similar action assuming you have tight tolerances? I know there are some Shirogorov flippers on washers, I just don't know how they compare.

If it is possible, why do we not see many flippers on washers these days?

 

[Misanthropia]

So I've been thinking about this. I have many super smooth knives on washers. A lot of them can be drop shut smooth when the tolerances are right. A good benchmade, a sebenza with polished washers, etc. From what I've seen, it seems like the bottleneck for smoothness is when the detent ball rides on the blade, and not the smoothness / friction on the actual pivot. My Sebenza are completely free when the detent ball is not on the blade, and a good 940 Benchmade can swing freely.

I may not be understanding the whole picture here, so I apologize in advance. Feel free to educate me. But if I understand this correctly, why do flippers need ball bearings? Couldn't you get a similar action assuming you have tight tolerances? I know there are some Shirogorov flippers on washers, I just don't know how they compare.

If it is possible, why do we not see many flippers on washers these days?

Bearings allow production knife manufacturers to cheat a bit on the complexities that go into making a good flipper. There are good washer based flippers, but they're pretty rare (Wilson Combat/Les George Eagle, new Hinderer's with their much stronger detents). It's easy for manufacturers to just use bearings because it's not feasible to put the amount of time or attention into making a washer based knife flip well on a large production scale. Custom makers, however, can and do routinely make good washer based flippers.

 

[Joshua M. Smith]

Hello,

I have a hobby of tuning fishing reels.

Some of the smoothest reels I've built use highly polished bronze bushings.

However, bearing reels are easier to *start in motion*.

Regards,

Josh

 

[PURPLEDC]

No they do not. Washer knives can be just as smooth and can flip just as hard. The most friction created in the swinging blade isn't from the pivot or its choice of bearings or washers. Its in the detent and its various factors including lockbar pressure. I have seen and held knives on washers that were every bit as smooth and fast as any bearing knife I have encountered. The appeal for bearings is they require much less effort to dial in. And in most respects the blade of a knife is self centering if everything was machined properly. And you don't need to be very careful with your pivot tension. If you were to take two knives one with bearings and one without and everything was identical except for that factor you would find the washer knife to be a little more sensitive to pivot tension. And your ability to center the blade will depend on the accuracy of the washers and how much give their is in its slip fit construction. Bearings you can crank on the pivot considerably more with no direct ill effect. I also like bearings especially if caged is because the open nature of its construction allows for flushing without much need to disassemble unless you really want to.

 

[PURPLEDC]

Bearings allow production knife manufacturers to cheat a bit on the complexities that go into making a good flipper. There are good washer based flippers, but they're pretty rare (Wilson Combat/Les George Eagle, new Hinderer's with their much stronger detents). It's easy for manufacturers to just use bearings because it's not feasible to put the amount of time or attention into making a washer based knife flip well on a large production scale. Custom makers, however, can and do routinely make good washer based flippers.

I don't honestly know how you could think that. Part of the reason bearing flippers cost more is because they are more intricate builds and need more attention to detail to get right. With washer knives as long as you are using high quality precision washers you shouldn't have too much issue as your blade stock and handle slabs are precision ground flat themselves. Bearing knives are much more complicated. Many times pockets are milled into the blade, handle or a combination of both. If that pocket isn't drilled perfectly parallel to the frame you will have a blade that binds because the bearings will pinch on one side and loose on the opposite side. If anything bearing flippers are harder to make on a large production scale given how much more machining is required and that machining is harder to replicate from knife to knife. Making a knife flip well is all in the detent and lockbar pressure.

 

[Lord_Balkan]

Bearings allow production knife manufacturers to cheat a bit on the complexities that go into making a good flipper. There are good washer based flippers, but they're pretty rare (Wilson Combat/Les George Eagle, new Hinderer's with their much stronger detents). It's easy for manufacturers to just use bearings because it's not feasible to put the amount of time or attention into making a washer based knife flip well on a large production scale. Custom makers, however, can and do routinely make good washer based flippers.

That makes sense. I suspected as much. I think I've prefer knives on washers only if their tolerances are great (CRK, Spyderco Taichung, etc) and bearings on others because of this. I can't think of many production flippers on PB washers.

I don't honestly know how you could think that. Part of the reason bearing flippers cost more is because they are more intricate builds and need more attention to detail to get right. With washer knives as long as you are using high quality precision washers you shouldn't have too much issue as your blade stock and handle slabs are precision ground flat themselves. Bearing knives are much more complicated. Many times pockets are milled into the blade, handle or a combination of both. If that pocket isn't drilled perfectly parallel to the frame you will have a blade that binds because the bearings will pinch on one side and loose on the opposite side. If anything bearing flippers are harder to make on a large production scale given how much more machining is required and that machining is harder to replicate from knife to knife. Making a knife flip well is all in the detent and lockbar pressure.

Maybe I spoke too soon. Seems like PB vs Washers require different skillsets / tools to make great.

 

[Steel130]

Bearings allow production knife manufacturers to cheat a bit on the complexities that go into making a good flipper. There are good washer based flippers, but they're pretty rare (Wilson Combat/Les George Eagle, new Hinderer's with their much stronger detents). It's easy for manufacturers to just use bearings because it's not feasible to put the amount of time or attention into making a washer based knife flip well on a large production scale. Custom makers, however, can and do routinely make good washer based flippers.

I agree with this statement, pretty much sums up what I came to say.

 

[RayseM]

I don't know the technical answers to give reasons for or against but my experience is that the bearing flippers usually provide smooth and fast deployment without ever needing to make pivot adjustments compared to washer knives.

I have owned and used as EDCs - Spydercos: Southard and Mantra and briefly carried a Domino, Hinderer and a ZT and a few customs found them all out of the box or eventually wanting in terms of ease of operation, though my current EDC is a 4" custom on washers that is very acceptable. Some smooth right out of the box but tight and needing "exercise" to loosen the mechanism, if not some adjustment to the pivot. Others, I just could never deploy without added wrist action. The Spydercos were the best of the production knives as new but degraded - dirt and dust - with use and needed some spa treatment or other mechanic work. Not all bearings are created equal. I've disassembled too many knives - polished the washers, lubed the pivots, added oil to the bearings and still ended up with sub par flippers. Only my Rockstead Chi flips as I prefer. If it were a top stud flipper rather than a thumb stud flipper it could be my ONLY pocket knife and I would be delighted.

On the other hand - my Thorburns, 3LD, Blomerus (huh - all South African makers) using IKBS systems have been superb flippers - front or top studs - and really fun too use. Never adjusted a Thorburn to get it right. Always right out of the box and after much use. I did need to send my Blomerus back for adjustment because the detente started to fail and the blade would open in my pocket - after 3 solid months of EDC as work knife - but the flipping action was unaffected. These IKBS knives could be deployed from any position - up/down/sideways/with my arm fully extended, any hand, fore finger or thumb as needed and closed with one hand too. These are essential features for me now with an EDC and these bearing flippers are outstanding in that regard.

My experience - my 2¢. Just sayin'

Ray

 

[sabre cat]

If bearings allow the maker to cheat on production, why don't we see more knives with bearings?
You would think companies like Spyderco and Benchmade would ramp up production for more bearings and less PB washers.

 

[evilgreg]

Are bearings necessary? No. This knife is one of my best-flipping flippers, and it's on washers:

That said, I think it's probably harder to get a washer flipper right; if I tighten down the pivot on that Kizer 3404 a quarter turn past perfect (flips great, no play) it won't flip that well any more.

On the other hand, this CKF Milk has the best action of any knife I've ever handled (Shiros, Thorburns, etc. included) and even if I over-tighten the pivot it still stays so free-swinging that I find it slightly disturbing:

I think it was Officer's Match whose similar claim made me seek out a Milk; he was entirely right . . .

 

[Officer's Match]

I do indeed have (and love) a CKF MILK. It is definitely my best functioning flipper in terms of deployment. The best "push button" flipper I have (as well as ever tried) is a Medford Viper, and it pivots on phosphor bronze washers. I believe it is substantially easier to manufacturer and assemble a bearing pivot flipper than a washer pivot flipper (and achieve excellent action). Most mass produced flippers are on bearings for a reason. I also tend to think washer based ones will outlast bearing pivots due to increased surface contact.

 

[michaelm466]

I have around 10 flippers, mostly various models of ZT and the 0200KW is my smoothest and easiest to open of all the ZTs (all others are on bearings), second only to the Buck 0830 Marksman (but that's also due to the strap lock)

 

[Barman1]

Bearings aren't necessary for smooth flipping as has been determined, but I'll go a little further and say that washers aren't necessary either.
The two Hogue X5s I've had use no washers or bearings at all and they fly open and would close to their detent point with just a shake.

 

[Cutlover]

I do indeed have (and love) a CKF MILK. It is definitely my best functioning flipper in terms of deployment. The best "push button" flipper I have (as well as ever tried) is a Medford Viper, and it pivots on phosphor bronze washers. I believe it is substantially easier to manufacturer and assemble a bearing pivot flipper than a washer pivot flipper (and achieve excellent action). Most mass produced flippers are on bearings for a reason. I also tend to think washer based ones will outlast bearing pivots due to increased surface contact.

If the washers have more surface area to contact, wouldn't it be the other way around? As in, wouldn't the bearings outlast the washers?

 

[Officer's Match]

If the washers have more surface area to contact, wouldn't it be the other way around? As in, wouldn't the bearings outlast the washers?

I think not, for the same reason you begin sharpening on a Spyderco Sharpmaker on the triangular points, and finish refining on the flats. Ball bearings contact (ie wear) on a small defined arc, whereas a washer has wide contact, spreading the "wear" over a comparatively larger area.

edit to add: This wear would effect both sides of what the washers/bearings contact, ie the blade tang as well as the scale. This is likely why some of the better bearing designs use a steel washer on the scale side for the bearings to contact (Olamic and Shirogorov come to mind).

 

[PURPLEDC]

If bearings allow the maker to cheat on production, why don't we see more knives with bearings?
You would think companies like Spyderco and Benchmade would ramp up production for more bearings and less PB washers.

That's the thing. I think people mistakenly look at bearings as a shortcut to fast and smooth action and that they require less attention to tolerances where that simply isn't the case. They have many more steps to the production and while they are more popular than they ever have been its only because caged bearings made them faster to assemble and manufacture. But I would wager that more companies aren't making them simply because of the extra work that goes into making one. Spyderco has a few with bearings. Domino, southward, mamba, Dice etc. But my southards were so poorly set up you couldn't really tell they had bearing pivots in the first place. And that is why I think many companies don't do them. They require a lot of finesse to do the right way.

 

[PURPLEDC]

If the washers have more surface area to contact, wouldn't it be the other way around? As in, wouldn't the bearings outlast the washers?

the greater surface area means a greater area to share the load. Bearings have a very fine line focal point of all stresses. Some however have an irrational fear that the bearings having that limited contact area will wear a channel prematurely into its contact points. But even on bare titanium it only goes so far and it stops after the bearing has been cradled enough and more surface area contact is created and a race is cold rolled. Its actually the same process used to create IKBS just at a much slower rate as it happens naturally and is not forced in a short period of time. Bearing flippers have been around for about 20 years now. And I have not seen a single instance of where a bearing flippers bearings caused a failure due to wear or anything else for that matter. The obsession of longevity in either case I find trivial at best. In either case it shouldn't matter. Even if a bearing flipper wore out twice as fast as a washer pivot if the bearing flipper lasts your whole life (which a good one will) does it really matter? Its like worrying about having a car with a top speed of 150 instead of 200 when you are likely never going to drive over 80.

 

[evilgreg]

But my southards were so poorly set up you couldn't really tell they had bearing pivots in the first place.

FWIW, I've bought a lot of Southards (~8 - 10 of them maybe), and I've been able to get all of them to be snappy flippers even though many I've purchased second hand were initially poor flippers when I received them. Most common issues:

1. Pivot too tight
2. Pivot area dirty
3. Pivot assembled incorrectly (backwards, usually--it doesn't seem like it should make a difference, but it does)
4. More rarely, detent too strong or too weak

I bought a couple where the seller warned "it takes a little wrist" or something similar, and after disassembling, cleaning, and tuning them up if necessary they've all ended up with pretty solid flipping action in the end.

There is some variation, though. My first one (gift from my wife) is the one I've carried most, and it's also the best flipper of the bunch. It's been flipped many, many thousands of times at this point, though, so maybe some of that is long term break-in. I dunno, even though I've tuned up a lot of them, this one still flips the best:

Oddly, the black coated ones are better flippers on average (I have no idea why that would be).

 

[TinyDog]

IMO I would much rather have Washers of high qauilty, Bearings may be smoother if the fit of the blade is perfect, if not the user will experience issues. Besides that until they make a self sealed bearing for use in knives, reasonable carrying is less forgiving as dirt is more of an issue, once again IMO... TD

 

[TinyDog]

evilgreg, the best bearing operated flipper I have ever owned was a Spyderco Southard... A nice blade