I have used Vessel Impact Ball torsion screwdriver bits for a while now, and they seem to deliver premium performance.
Vessel Impact Ball bits are advertised as being shock-absorbing, and I also tend to use them with cordless screwdrivers, drills, and hand tools.
Their geometry is definitely different compared to most others on the market today, with a shock-absorbing ball positioned right in the middle of the torsion zone.
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I like this type of screwdriver bit for 2 reasons – the insert bits are a little taller than standard insert-style bits while still being much shorter than power bits, and I love the compact cases they come with.
Plus, if I’m being honest, there’s a novelty factor – they’re different, and that sometimes makes mundane tasks just a little more enjoyable.
I have been using the sets and assortments featured below, and would buy them all again.
Vessel 5pc Phillips #2 Bit Set with MAG Charge Holder
This could be a good “try me” starter pack. It comes with a compact holder, 5 Ph #2 bits, and its holder doubles as a magnetizer and demagnetizer, which has value in itself.
Vessel 10pc Bit Assortment + Bit Holder in Pop-Up Case
If you’re looking for a more functional assortment, this 10+1 set comes with a range of sizes plus a bit holder in a neat compact case.
Vessel 30pc Bit Set + Bit Holder in Slide Case
This is a larger assortment in a compact case. The second row slides out when the lid opens, for easier retrieval.
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Vessel 5pc Impact Ball Torsion Power Bit Set with MAG Charge Holder
I also like Vessel’s power-style screwdriver bits, although I don’t have many yet, just this small 5pc set.
It comes with Phillips #2 (2x), Square #2, Torx T20, and Torx T25 bit styles.
The bits are made in Japan, and the bit holders in China.
In my experiences thus far, the fastener fitment has been great, and the bits seem very durable. I would absolutely buy them again!
The insert and power bits are available in other assortments and also in bulk packaging, although selection can be limited and hard to decipher.
For instance, you can get a 15-pack of Phillips #2 power-style bits for ~$22. Other sizes and styles are available if you’re willing to search a bit, such as a 25-pack of Torx T20 bits, which are priced at ~$44.
Note: Be careful with imported Vessel bits purchased from overseas sellers, as they have a slightly different hex standard that doesn’t work well with USA-standard impact drivers.
I haven’t looked into the exact standards, but have learned by mistake that 1/4″ hex power bits imported from Japan have different locking end dimensions than USA and EU-standard bits. As such, they can be used with cordless drills and certain hex bit holders, but won’t lock into [most?] impact driver chucks.
MM
In my opinion the image titled “Absorb Shocks!” has some misleading text on it.
The little red arrows pointing at the ball should be labeled “stress concentrations”, and the little ball in the middle should be labeled “Useless marketing feature”. It is the two narrow portions, colored orange in the image, which flex and relieve shock. The ball is actually counterproductive, increasing the chance of a fatigue failure where those red arrows are pointing.
I’m sure these perform well, as all Vessel screwdrivers I’ve used have, but I don’t buy that the ball does anything other than look interesting.
What is the red ball looking thing for in the pop-up case? Is that a button to release the bit holder?
Richard
It seems to me the ball is intentional to get it to shear in failure instead of splinter. (As you mentioned) it creates a stress concentration. I’m not sure if that feature would add a practical benefit. I’m surprised the marketing material seems light on that end.
If this was Milwaukee it would at least come with “2x more torque before failure” or something vague like that.
The one thing I could think of is if the max stress (typically) is in the middle and they made it thicker so it is stronger (can flex more). Like how a bridge is curved most where the tension stresses are highest (the middle). But again without numbers or claims it’s hard to say.
MM
Ah, so your theory is that might be designed to break next to the ball to act as sort of a “fuse” for lack of a better word? That’s possible, I suppose, but I don’t think that’s very likely. I think it’s just a visually interesting twist on the classic (by now, anyway) idea of a torque limiting extension–the same kind of idea as as those “torque sticks” for impact guns.
Bridges or beams which are supported on both ends experience the maximum stress in the center with linear loads. However, this is *torsional* loading, or twisting, so that is not applicable.
jmouw
A bridge is not curved in the middle where tension stresses are the highest. Bending moment, or torque, will be the greatest at the center of the span. Any arch or support structure is there to deal with that bending moment.
A drill bit such as this will be under a shear stress, which will be greatest where ever the shaft is the thinnest. I too see no point of the ball in the center of the bit.
Stuart
With the case – yes, it pops out with a squeeze. I have my 5pc and 30pc cases at-hand, but the 10pc must have grew legs and walked off. I’ll try to do a video demo if I can track it down.
Regarding the ball feature, consider what happens at the center of the torsion zone – that’s where the maximum stress concentration is going to be.
How do you design a torsion zone to absorb more energy? You make it thicker. The ball is localized at the point of maximum stress.
Does it make a difference? I’m not sure – I haven’t broken any bits yet.
Alex
Pretty sure torsion stress is constant along the length
Stuart
Sorry, maximum deformation. (Or at least that’s how I visualize it, with bits treated as solid shafts supported on both ends.)
Yes, shear stress in a solid rod varies with radial diameter.
I’m not sure how the mechanics work with the ball, but I visualize it as two torsion zones interrupted by the ball zone, rather than one continuous torsion zone with three zones.
The ball is optimally placed in the center.
My assumption has been that two torsion zones are stronger than one of combined length.
MM
On what physics are you basing that last assumption? I don’t believe that to be true at all.
Stuart
It could potentially serve to also reduce bending? Many brands’ impact bits have two torsion zones rather than a single very long narrow-shaft zone.
Koko The Talking Ape
I’m with MM and the other skeptics. The ball has no conceivable structural function.
Impact-rated bits have thinner shanks (supposedly) to REDUCE torsional stiffness, so that impact shocks will actually twist that shaft slightly like a spring, reducing transient peak stress.
And as MM says, any sudden or discontinuous (in the mathematical sense) change in cross section creates a stress concentration, i.e., an invitation for failure. If they wanted to create a pointless feature, at least they could make it swell smoothly from the narrow shaft, instead of bumping out like that.
The fact that they haven’t failed in actual use doesn’t make the “feature” any less pointless.
MM
The center of the “torsion zone” is NOT where the maximum stress concentration is going to be. This is simple torsion al loading. If the “torsion zone” were a normal cylinder shape, like the red part on Milwaukee Shockwave bits or the Yellow part on Dewalt Flextorq, the stress will be uniform throughout that section.
The colored picture actually shows torsional stresses via color code. The blue colors are low stress, red is high stress. If you took the ball away and replaced this with a Milwaukee-like design the “torsion zone” would be uniformly orange–those red stress concentrations at the transition to the ball would disappear entirely.
“How do you design a torsion zone to absorb more energy? You make it thicker”.
No. Making a spring thicker makes it stiffer, but that doesn’t necessarily means it absorbs more energy. Imagine a screwdriver bit that’s a full one inch diameter. By this logic it would absorb more energy than a flex bit…but I think we both know a bit that thick isn’t going to flex at all, and thus it won’t absorb anything. Length is another variable which matters. Consider a 1-foot-long piece of 2×4. Can you twist that in your hands? No. Now take a 10 foot long 2×4, clamp one end in a vise, and try and twist the other end…it’s pretty easy to flex it a few degrees. This is just a simple torsion spring, nothing more. They made it fancier than it needs to be so it looks cool. I doubt these will break, Vessel makes quality tools, I’m sure they know well that even with the stress concentrations at the ball the bits will perform well because they will fail in some other way first.
Koko The Talking Ape
I agree with and admire your physics, sir!
Stuart
For Vessel’s industrial bits, they do have different torsional diameters depending on soft or hard torque, I’m guessing because the thicker torsional zone can withstand higher impulse shocks, whereas the thinner torsional zone can twist further.
I find it hard to believe the ball is purely cosmetic.
Other brands also have dual torsional zones, and so perhaps that’s simply the benefit here, with the ball serving as a more aesthetic separation, but a functional separation nonetheless.
MM
All other things being equal, a thinner torsional zone would twist farther than a thicker one, that is absolutely true. And likewise a longer torsional zone would twist farther than shorter one of the same diameter.
I guarantee you the ball is purely cosmetic. There is no benefit to having multiple torsion zones. Two 1/4″ long zones separated by a significantly thicker central obstruction would have the same torsional stiffness as a single 1/2″ long one. This is an elementary engineering problem, series and parallel springs. In this case it is two torsional springs in series, you can easily look up the math for this. Notice that most torque limiting tools just have a straight narrow section–this isn’t just impact rated bits like Milwaukee or Dewalt Vessel’s industrial line, there are also torque limiting extensions used for auto lug nuts, aka “torque sticks”. Those are all straight. Any deviation from straight is just getting creative with the shape in order to look different. These strange “double” or “ball” designs do work, they just don’t work any better than a single section.
By the way, Torque Test Channel has good high speed video on how those “torque sticks” work if anyone is curious about the general idea behind these things.
https://www.youtube.com/watch?v=JVY0e5sdWx4
Andrew
I suspect you’re correct.
The following patent from Black & Decker describes their version of the bulging mid section as ‘ornamental’:
https://patents.google.com/patent/USD789761S1/en
It’s the best patent I’ve ever read in terms of brevity, a single claim and a few well drawn figures!
‘The ornamental design for a torsion bit, as shown and
described.’
I have to wade through patents regularly, and they are often mind numbing, so this at least is refreshing.
I think these bulging sections are no more than design flourishes, nothing wrong with that, but no new physics. Every manufacturer will no doubt want their own look, including vessel.
One point of note, if you look at the figures in this patent in detail, the radii around the bulge are smoothly varying. In other words, there are no curvature discontinuities. I think this will be deliberate to avoid any critical stress concentrations (the stress will be well modelled in FEA for this relatively simple object). It will also be more realistic for machined bits, where tools have finite curvatures.
There is no need for a separate ‘mechanical fuse’ as discussed further down the thread. The ratio of length/radius, and the material tensile properties naturally give a limit to ultimate strength.
…
(I’ve just run one more search, and Milwaukee similarly have an ornamental claim patent for their smoothly necked version: https://patents.google.com/patent/USD623036S1/en )
Albert
Does Vessel make JIS phillips bits? It looks like even that 30 pc set doesn’t have them. I occasionally need them, but don’t want to carry complete JIS screwdrivers.
Jeff C
Check out Vessel # A-16479 & A-16621 three piece bit sets.
Stuart
Some of their tools explicitly say that the cross #2 fits US Phillips #2 as well as JIS #2.
https://www.amazon.com/Vessel-Megadora-Impacta-P2x100-Screwdriver/dp/B003BI8HHQ?tag=toolguyd-20
Compatibility can be hit or miss with Japanese brands unless they explicitly mention compatibility.
I bought a Nepros wood-handled Phillips #2 screwdriver that’s specifically marketed as a PH #2 driver, and its fitment with PH #2 bits is absolutely terrible.
Even if the Vessel bits might be advertised as cross-compatible, that’s going to be a trial and error determination.
Jeff C
Here is a good read on the the confusion that is JIS:
https://www.webbikeworld.com/hozan-jis-screwdrivers-review/
Jeff
Jim Felt
I have a set of Vessel full size PoziDrive demo handle screw drivers. They’re as solid as my Wera demo drivers. Though I like the laser tip Weras general full size drivers over anything else I’ve used to at this point. My Klein sets are languishing. Plus in time the black “rubber” tends to grey out. Which just bugs the heck out of me. Reminds me of the eventually stinky plastic handled Craftsman effect.
Matthewj
At the risk of revealing ignorance, why would you want a ‘shock-absorbing’ impact bit in the first place? Isn’t the transmission of shock (or impulse, I guess) the whole point of an impact tool? I’d think that you would want the stiffest shaft possible, while allowing for toughness.
Koko The Talking Ape
It’s a matter of degree. You want enough shock to turn the fastener, but not enough to break the bit. It seems like it’s easy to make a driver that creates enough shock (by slapping a steel driver gear against an anvil), and in some cases that’s too much shock.
You’re right that toughness is important, but hardness is too, to reduce wear, and increasing one typically reduces the other. But if the bit is made to absorb some shock, then the need for toughness goes down (because the peak shock is lower), and then you can make the bit harder (or cheaper.)
Joe
Wouldn’t absorbing shock be counter to the purpose of using an impact driver? I don’t doubt that these are finely crafted bits, but. can’t understand why you’d want to incorporate a feature that absorbs the energy deliberately transmitted by the driver. Fortunately, I’m highly skeptical that this design would absorb shock anyway… but it certainly seems like an odd selling feature.
Stuart
Most impact-rated accessories have shock-absorbing torsion zones these days.
Let’s say an impact chuck is turning but a bit isn’t moving. Work is being done and energy is transmitted through the bit. If it doesn’t go somewhere, there’s increased risk of bit breakage, which used to be a common mode of failure.
A torsion zone absorbs some of that energy elastically and doesn’t suffer permanent deformation.
The how and why this might be better than a single torsion zone is more complicated.
MM
You and Matthewj do raise a very good point: in some ways, a shock-absorbing impact bit is counterproductive. As a thought exercise, let’s say we made a super flexible impact bit, one that really did absorb a massive amount of energy–such a bit would make the impact driver useless because it would cancel out the impacts entirely. It would be like trying to drive nails with a feather pillow taped to your hammer. But these bits don’t cancel out all the energy, they just take some of it. And I think that’s not a bad idea. These days impact wrenches are pretty powerful and it’s certainly possible to strip heads or break screws or whatever else if you’re going pedal-to-the-metal with a solid bit. Can you work around that with careful trigger control? Absolutely. But it’s nice to be able to take a shock-absorbing bit that you know will let you drive screws with the trigger floored and not have to worry about breaking things. Now when you need more torque, say for driving some big lags…it would be silly to use any kind of shock-absorbing bits for that.
I’m sure these do absorb shocks, I’m just skeptical they’re better than anyone else’s. Shock absorbing bits are nothing new, this is just a me-too product with a new visual gimmick.
Blocky
I’m confident that the shock absorption doesn’t result entirely in energy loss, but rather reduces the peak momentary energy transfer. The twist of the torsion zone in counter rotation also rebounds in the drive direction between impacts, Some of the energy may transfer through the tool to the operator, but most of it will uncoil as drive force on the fastener.
Of course the fasteners themselves, driven with high impact forces, also twist and sheer.
Koko The Talking Ape
Exactly. And more precisely, these impact bits both remove some some energy (turning it into heat) and also store and then release some of the energy.
So if you have a graph of energy over time, the total energy (the area under the curve, integrated over time) would be slightly less, but more so, the graph would have a lower peak and a longer tail.
(Conflating force and energy for a second), that peak force is what breaks loose fasteners, and also can break bits. But the total force is what TURNS the fastener against resistance.
And apparently impact drivers can create more peak force than is strictly required, and that can also break bits. So these impact-rated bits reduce the peak force, but also spread some of that force over time, so it still is doing useful work by turning the fastener. It’s true that some force is lost, but I’d bet not much. (It wouldn’t be hard, in principle, to measure how much force is lost by measuring how hot the bit gets.) 🙂
Koko The Talking Ape
Er, thinking about it more, I guess the driver and bit have to overcome both static and dynamic friction in the fastener to turn it. If the peak force overcomes the static friction, the continuing force still has to overcome dynamic friction, and when that force falls below the friction load, the fastener stops moving. So shifting some of that force back in time does result in more wasted energy. The energy over time graph has a longer tail, and therefore greater area below the threshold energy level required to turn the fastener. Oh well!
Doresoom
No 5/32 hex in that 30pc kit? That’s surprising – it’s a common size thar’s used in 1/4-20 flat head and button head screws. Maybe they figure the 4mm hex is close enough?
Blocky
By hand and eye, I can’t measure the difference btwn 5/32 and 4mm — probably why it’s so ubiquitous in assembly furniture.
Great assortment, although I have never encountered R3 in the field. Rather than slotted bits, I have a few security torx in my wera bitcheck30.
MtnRanch
I’m still trying to figure out why I’m taking a tool that is designed specifically to deliver a shock to the bit and fastener and then inserting a “feature” to absorb that shock.
There has to be a mechanical engineer or physicist out there who can provide a cogent explanation. Manufacturers’ marketing people have not done that yet.
Koko The Talking Ape
I never completed my engineer training, but I’ll give it a shot.
You do want SOME shock delivered to the fastener, but EXCESS shock doesn’t help turn the fastener, and can damage bits. And apparently that’s what some current impact drivers can do.
So these shock-absorbing bits reduce the shock sent to the fastener, but apparently not enough to keep the fastener from turning.
And as I said earlier. bits have to balance hardness against toughness. Toughness means less breakage, but hardness means less wear. If the bits don’t have to be as tough (because they’re designed to absorb shock), maybe they can be made harder, and thus longer-lasting.
Stuart
Consider a fastener that won’t budge, and an impact tool that’s operating as expected. You have a screwdriver bit transmitting the force. If one end of the bit is turning and the other cannot, something has to yield.
A few years ago, what would happen is the bit tip would shear off, as that would be the narrowest diameter and weakest point.
A torsional zone smooths out the shock a bit.
It acts as a spring or cushion, similar to a car’s suspension or running shoes. But, instead of storing energy in compression, it stores it in torsion.
The result? Less tip breakage. Push modern bits too far, and they can still break, deform, or fail in different ways.
Mark M.
I would pass for no other reason than the carnival barker marketing copy. “Absorbs Shocks!” “30x” [30x what?] and then some little molecule graphic that signifies….? What a mess. Might perform well, good on them if it does. I’ll spend my money on brands with a more professional, less gimmicky tone.
RickC
I’d like to ask if Stuart would do a thorough review of the current ISO/DIN standards that Vessel uses now for crosspoint or + drivers. One of the main problems that confuses people is the generic use of “JIS” for current ISO/DIN drivers (I’ve also seen them called Japanese Philips or even just plain Phillips, but that is incorrect) similar to when they’re getting a “Coke” when they mean any brand soft drink or making a “Xerox” when they’re using any brand copier.
I have some Vessel 2200, 700, and 9900 series drivers and they work very well on Japanese and regular American Phillips screws. No cam out. I don’t use my Milwaukee drivers any more.
Stuart
I generally don’t come across many JIS fasteners. I suppose I could order a box of JIS #2 screws (M5?), but there’s no guarantee that any findings will be universal.
The screwdriver standards are also all over the place. I’ve used Japanese Phillips #2 drivers that don’t work well on Phillips screws, and others that are described as PH/JIS but seem to be indistinguishable from regular Phillips drivers.
It’s absolutely a mess, and to be honest I’m not sure I can clear it up.
Elagabalus
Disappointed there is no JIS option.
Marcelo
The bit that I love and use for many years on my impact driver is a indestructible Makita Elite. It’s a made in Japan mirror polished torsion bit. Came in pack of 3 units, never used the second or third. Even hasty contractor can’t manage to break it.
Emilio+Gonzalez
Looks gimmicky. Are these JIS standard bits? I could never get a straight answer from Vessel. I don’t like their poor tech support and prefer Koken Tools bits and holders. Vessel is also too proprietary. Their bits don’t work with other holders well.
Brian
I’m late to this party… as far as the torsion zone on these bits. The engineering and numbers concerned are beyond me. But out of all of the comments there seems to be one point that has been overlooked. The placement of the ball allows for these bits to be used in both the 13mm Japan collet as well as the US standard.