Shown here are a couple of my PB Swiss hollow ground screwdriver bits.
I’ve got a couple more hollow ground bits in other places, and my main slotted screwdrivers also have hollow ground tips.
Hollow ground screwdrivers – as opposed to insert and power bits – are manufactured a little differently. If there’s interest, I’ll talk about those in a follow-up post.
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You can see what these offer, at least compared to typical tapered slotted screwdriver tips and bits. Basically, you get a flatter tip shape that better fits slotted screws.
You get a more precise fit, and that contributes to greater control (at least in my experience), less slipping, and less damage to the fastener head.
When you have a tapered screwdriver tip, torque is generally applied to the edge of a slotted screwdriver where there is slight engagement. Here, you get more engagement within the slotted screw head.
Hollow ground screwdrivers and bits are simply better for fastening applications.
Do you need them? That depends. This type of screwdriver tip is popular in gunsmithing. Outside of that, you’d use hollow ground screwdrivers and bits where you’d like to avoid damage to slotted screws.
Some toolmakers describe these as non-marring slotted screwdrivers.
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But if you need standalone screwdrivers in a range of sizes, Grace is known as the de facto go-to.
I like PB Swiss bits and screwdrivers and know them best, but I use others when they’re more convenient at reach. When I’m working on electronics, I sometimes reach for ESD-safe screwdrivers, and they have standard tapered tips. In those applications, it doesn’t really matter since I’m usually dealing with very low-torque fasteners or adjustments.
They can handle a bit of abuse too, but I usually reach for cheaper screwdrivers for tasks that can lead to damage.
This is a type of slotted screwdriver and tip style that you should know about, but not necessarily run out to buy without a clear need for.
Stuart_T
The MegaPro (now labelled Alfa) slotted bits are also hollow ground, as well as the gunsmithing bits from Brownells, which are available in many, many sizes. (Can’t remmber who makes them but I believe they are made in the USA.)
Nathan
I want to say the DeWalt and the apex ones are too and I bet tekton ones are also.
I have a few but I rarely use them or my screwdriver
But like you say great for engagement of the flat and they work well for 1/4 turn panel fittings
fred
I have a set of bits from Wheeler Engineering that offers a choice of different ones to help precisely fit different screw slots. These offer varying thickness as well as widths. I also own a set (20pc.) of Brownell’s gunsmith screwdrivers and a few from Grace and Pachmyr. With bits that are used to fit extremely narrow screw slots one needs to take it easy with the torque – as breaking bits is a real possibility. I think that this may be true for hollow-ground bits in general (even more so with ones made from inferior steel) – in that over torquing can break bits. But over torquing is never a good practice. A chisel tip bit might be less likely to shatter – but can certainly cam out and ruin the screw head. In our fabrication shop we used both manual and powered torque screwdrivers to help avoid these issues.
https://www.amazon.com/Wheeler-Engineering-Gunsmithing-Screwdriver-Construction/dp/B001C63M7O
https://www.brownells.com/tools-cleaning/general-gunsmith-tools/screwdrivers-sets/fixed-blade-screwdriver-master-sets/?sku=080001214
fred
I see that Amazon lists a large Wheeler bit set as being on sale:
https://www.amazon.com/Wheeler-100pc-Professional-Screwdriver-Set/dp/B0BRTC91SZ
They also list a set of USA-made Forster screwdrivers:
https://www.amazon.com/Forster-8-Piece-Gunsmith-Screwdriver-Set/dp/B003F6FKBA
MM
I have two sets of Brownell’s gunsmith drivers, one standard assortment with 40-some-odd slotted tips, and another specialty “extra thin” assortment with another 18. They are quite nice quality in my opinion, precision is excellent. But even with that many I still find myself having to grind custom bits from time to time.
And speaking of gun screws with super narrow slots: those are often meant to be used with strongly tapered drivers–sometimes called “turnscrews”. The tips on these look like a double-bevel sculptor’s chisel, they are beveled on both sides and come to a sharp edge. I don’t care for these because you have to put extreme pressure down on the driver for it not to slip out of the slot. They’re basically the exact opposite of a parallel tip: they cam out easily, but they are also robust. However, they were for a time the standard, it is very common to find them as part of the accessories cased with fine 19th century guns. They also appeared in multi-bladed folding knives of the era. That is an interesting historical oddity, as it seems like the worst possible design to come up with for a screwdriver. I assume the idea was to maximize the surface area for decorative engraving by making the screw slot as narrow as possible?
Jared
I’d throw out Chapman Manufacturing as well. American made and high quality. They’re a bit unique though, so maybe not best for everyone.
https://chapmanmfg.com/
CA
And Chapman even offers JIS bits in a couple of sizes to boot. Quality bits.
Mopar4wd
I’m pretty sure Chapman bits made here in CT are also hollow ground.
D3t
Yes. https://www.youtube.com/shorts/ce6wlE6xuJo
Aaron SD
I’m interested in how they’re made. It would be good to see a side-by-side view of the profile to see the difference with and without the taper. Are there any other differences?
MB
Chisel tips look like a V. Hollow ground were ground on a round wheel so it’s a swoop as you see in the top pic.
KokoTheTalkingApe
I believe the chisel tip ones are forged to flatten the tip, then the sides are ground to make the tip the right width. Or at least, the shank sort of looks squooshed near the tip as if it had been hot forged, and you can sometimes see grinder marks on the sides of the tip.
IF that’s how they’re made, I guess the forging would strengthen the tip, and maybe call for a different tip hardening process, if one is used at all. The hollow ground tips aren’t forged, so they might need a different hardening and tempering process, and maybe different steel.
Wayne R.
My few old school Keystone slot drivers are flat ground, but the 6-in-1s and all the 1/4 long “power” bits, 4mm bits (and tiny Klein bits (3.5mm?) I have are hollow ground Cabinet tips. I have a small insulated Wiha driver that’s hollow too.
The Wiha Precision set’s slot drivers are a mix, the bigger three are flat and the smaller ones are hollow, but they’re all cabinet shafts.
Using any of the flat drivers is pretty rare anymore though. The only slotted screws I recall tearing up a bit are the peened-over pivot screws on old scissors that are too loose or too tight. And using an under-sized bit (of any type) is always the worst choice.
Fowler
All of the generic S2 70mm power bits I have are hollow ground
TimL
Not exactly on topic, but is there a specific material of metal for these? I have some small sized hex/allen bits (made for RC cars) that i love, but the manufacturer cannot give me the material info. I want to order larger sizes since a lot of the generic (grey) ones you can get in bit-sets feel like they round off too easy.
Here is an example of one I have. Looking for more like this.
https://www.amazon.com/Team-Associated-Driver-2-0mm-Standard/dp/B0051W6T66/
Ram12375
I’m an RC guy too. Not a direct answer to your question but this is how I solved the same problem. Wera hex plus. Absolutely love them. My opinion is that the smaller you go the more benefit you get from the hex plus. I’m a 1/10th guy so 1.5, 2, and 2.5mm are my go to. I just wish I could get 1.5mm grub screws for pinion gears in a torx head. Doesn’t matter what driver you use, they get torn up from over torque so easily.
MM
I was into R/C years ago, and remember having a special 0.050″ driver for the setscrews on motor pinions as that tiny size was easily stripped out and ball-ends of that size were easily broken. Mine was made by Trinity.
Anyway, I don’t think the exact alloy matters much, pretty much any grade of tool steel would work so long as it is hardened & sized properly. The fitment is most important especially on small fasteners. A quality brand like Wera or PB Swiss would work fine.
Stuart
The type of tool steel used depends on the brand and application, and the heat treatment could vary.
S2 tends to be common.
Corey Launch
https://www.miponline.com/gen-2-tools.html
Absolute best tools for small hex screws (RC and other) They are pricey but are the best bits I’ve ever used.
Nathan
Rc guy also. I use bondhus ones but will say I have stripped out a few 0.50 ones and a 1.5 and I just expect it. But when I moved to insert bits in my driver handle vs a l key they seemed to last a lot longer. Reminds me I might need to get back into it
Cbas
I second this. MIP are the best hex drivers you can buy for RC. Worth the extra money. I wouldn’t use anything else. I have purchased 3 extras in the common sizes in case they ever go out of business, as RC companies sometimes do.
Lance
Check out the Wiha 75965 kit. I have it now and WISH I had something like this back in my RC days. Mini 4mm hex drive system.
It’s got way more than you need, but more is always better and it comes in super handy in general to have a fully featured mini set.
Champs
These are exactly what I need for my house full of antique hardware—or at least I would if the place hadn’t been through so many “landlord special” jobs where you have to remove paint just to find the fasteners, never mind getting purchase on the flat screws.
Call it sacrilege, everything I restore uses Phillips. The crock pot’s full of hardware, anyway.
Nathan
Other than to keep a look I don’t consider it sacrilege. Guns that still use flats are mostly antiques like furniture. If exposed sure maybe keep a flat in it. But I see nothing wrong with updating
William Adams
The original design intent was that screws were “clocked” so that when properly tightened the slot would be in-line with the axis of the bore — that way, one could be certain the weapon was correctly re-assembled before torque measuring tools were widely available.
This was done by making the screw with a longer head than was needed, tightening it in place, marking it, then cutting it to length and machining the slot.
Stuart
Thanks! Looks like I learned something today.
fred
Me too – thanks William
MM
You can see an excellent example of the method William mentions in this video, starting at 12:55 timestamp.
https://www.youtube.com/watch?v=qUXoNUzAyvk
Also note the extremely tapered chisel-tip screwdriver used at 13:06, the exact opposite of the hollow-ground type.
fred
Very interesting. Looking at the entire process one can see why such shotguns command six figure prices. I’m not a hunter – but an uncle was – owning a pair of Purdy’s that he treasured. My “handcrafted” Purdy’s are way less costly and are more useful for applying paint and varnish
Jared
I would be interested in hearing about the practical difference between hollow-ground and parallel-tip screwdrivers. Maybe there’s no real difference since the faces of hollow-ground screwdrivers are parallel (or close to it) for a good portion.
I bought a set from Grace from Lee Valley based on your recommendation in an earlier post – I’m quite happy with them. PB Swiss pricing is on a whole other level, especially in Canada.
Stuart
Insert bits are typically designed to be more cost economical and even consumable. Screwdrivers are typically longer lasting, and they also command a higher price point.
From what I can tell, screwdrivers with parallel tips undergo more precise machining whereas insert and power bits can be brought close. As I see it, hollow ground bits and tips seem to be *effectively parallel* whereas stepped parallel screwdriver tips seem to be a little more precise.
fred
In our production environment we bought bits in bulk and kept track of bit use – driving only x-number of fasteners before changing out a bit. Sometimes x was close to 1. We also sometimes specified SS bits to help reduce the possibility of leaving behind detritus that might rust.
In our remodeling and plumbing businesses, we tried to inculcate the notion that it was better to scrap a bit somewhat prematurely than risk damaging a fastener that was part of finish-trim.
MM
I don’t believe there is much of a practical difference. The point is that the tip has parallel sides, and hollow grinding is one of multiple methods that could be used to manufacture that, but the end result works the same. I’ve seen some “parallel tip” screwdrivers that have an obvious step where the tip is ground, for example the Grace branded gunsmith’s screwdrivers. You can see what I mean in the second photo in this listing:
https://www.leevalley.com/en-us/shop/tools/hand-tools/screwdrivers/drivers/70923-grace-gunsmith-style-screwdrivers
My engineering education tells me that this is a stress concentration which could result in the tip failing but I’ve owned screwdrivers like that in the past and I never found them to be particularly fragile.
I think it’s just a matter of how the grinding wheels are oriented in the machine that finishes the tips, sort of like how Arter and Blanchard type grinders orient their wheels in different directions but they both make flat surfaces. The important thing is that the faces of the tip are parallel, exactly what method is used to cut or form the tip into that shape doesn’t matter much in my experience.
Autolycus Too
PB Swiss make probably the finest screwdriving toolery in the workd – closely followed by Wera and Wiha. You’ll pay top dollar for the PB Swiss – but even their driver bits have a Lifetime warranty, so they are – effectively – the cheapest you’ll ever buy.
Hector
have 10 1″ slotted bits in different sizes from Felo (german manufactured), along w/ a full set of Grace square handled slotted screwdrivers. The Felo are top quality, have harder tips than the Grace, and are much less expensive than PB Swiss. They are a very slight step down from PB, which are crazy nice.
Charles
MegaPro are undoubtedly the value leader and I’ve never had one fail.
As a totally unrelated question – does anyone make a replaceable bit that is a tiny blade? I think it would be helpful in a set where you might need a blade only occasionally – to trim something, cut tape or whatnot.