Sizing of 1/4” hex shanks

[Bill PhinnParticipant @billphinn90025]

Michael’s recent question about the declared shank sizing of Dremel bits (the motivation for which seems to have been slightly misinterpreted by some) put me in mind of a quite different sizing issue that I’d be interested to have people’s views on.

About six months ago I bought a set of HSS 1/4” hex shank 3-flute countersinks. As you can see from the two photos, the across-the-flats measurements are rather short of the declared size. My feeling is that this size discrepancy isn’t acceptable, whether the intention is to use the bits in a hex bit holder or a three jaw chuck.

I should point out that:

a). none of the eighteen AF measurements in the six-bit set is as big as 1/4”, the biggest being 6.29mm, and the smallest 6.07mm, with half being under 6.2mm.

b). all three of each of the six bits’ AF measurements are different from one another by between a perfectly acceptable (to me, at any rate) minimum of 0.03mm and a surely unacceptable max of 0.20mm.

c). some of the bits are, as you’d expect, a decidedly wobbly fit in a 1/4” bit holder.

d). the seller gave me a full refund whilst being quick to point out that he’d sold hundreds of these sets and nobody had ever reported the problem I was reporting. I am perfectly prepared to believe him, though if his reply was intended to be reassuring it wasn’t.

 

[DC31kParticipant @dc31k]

Please look up ISO1173.

https://cdn.standards.iteh.ai/samples/23588/ab32510c11f74bfbb198fcd63d2b9a04/ISO-1173-2001.pdf

[Tony Pratt 1Participant @tonypratt1]

Sadly it doesn’t surprise me at all, nowadays the consumer is the quality control. I suppose they do the job as you say?

Tony

[HopperParticipant @hopper]

I would have thought those were intended for woodworking use in handheld pistol drills, so unlikely to be of the levels of precision we are more used to in precision metalworking kit?

Likely made undersize so they go in and out of the typical carpenter;s quick change 1/4″ hex holder quickly and easily?  A bit of slop never slowed a carpenter down. As long as they don’t fall out, he will be happy.

And if they are cheap ones, quite likely all over the place in line with low cost manufacturing standards.

For more precision suited to use on steel etc in milling machines for model engineering etc, I think I would be looking at the more expensive countersinks with the ground round shanks.

[BazyleParticipant @bazyle]

Edited out previous reply. I was thinking of screwdriver bits where the working bit is smaller than the hex shank.

[JasonBModerator @jasonb]

Looks like you picked up a bit of a Lemon, measured an assortment of mine for comparrison. If you are putting them into a cordless with built in hex recess holder then there is more risk of wear to the holder, if you are just using a separate hex recess holder or even a drill chuck not such an issue.

From The Top

Trend 5mm TCT drill/csk

Trend 4mm TCT drill Csk

Kreg Pocket Hole drill

Bosch Lip and spur drill

haffle sprung jig drill

Screwfix drill bit

Toolstation Drill bit

Tec Driver

Wera #2Pz

All except plain shank jig drill quite close to 6.35 and withing the upper and lower limits of DC’s table 5 which is the recessed one

[Bill PhinnParticipant @billphinn90025]

Thanks a lot for the replies.

Yes, I intended them mainly for woodworking (though I would also have liked to use them in my mag drill). Other 1/4” hex shank tools I own by Wiha, Milwaukee, Dewalt et al. are probably mainly intended for woodworking too. After a quick measuring session all but one of about a dozen I’ve measured is within the spec DC31k has provided.

For quality work I’ve just bought these, which, interestingly, come in two versions: a round shank version (mine) and a triple-flat shank version:

 

[Bill PhinnParticipant @billphinn90025]

Well, here we go again, this time with square drives on two recently purchased offset handles. Do either the 1/4” or 3/8” come within a recognised standard?

[egaParticipant @ega]

As to the hex shanks, Festool offer their “Centrotec” holders which centralise the bit and minimise wobble. They are intended for Centrotec bits but standard ones can be turned down slightly to fit.

[Bill Phinn]

On Bill Phinn Said:

[…]  Do either the 1/4” or 3/8” come within a recognised standard?

 

“Easily Detachable” perhaps

MichaelG.

[Neil AParticipant @neila]

BS 4006 covers the size of square drive sockets and wrenches.

1/4 square drive. 6.260 min 6.350 max

3/8 square drive. 9.435 min 9.525 max

All in millimetres of course.

I was always told that BS was the lowest common denominator of the manufacturers. That was by someone who was on some of the committees!

Neil

[old martParticipant @oldmart]

I have been lucky with the 1/4″ hex shank toolbits which are intended to fit in screwdrivers and small impact drivers. I have just bought one of the 12V Lidl drills with the 10mm chuck which comes off to reveal the 1/4″ hex drive. It comes with a good set of drills and screwdriver bits and the drill box for £13.99, they were £ 16.99 before. You have to already have the charger and battery, though.

[PeteParticipant @pete41194]

Many of these tool shanks are designed and meant to be a slip fit. That spring loaded ball on the square shank is what does the retaining well enough for whatever tool is on it to not to fall off. It’s there, but on lower priced tools I’ve seen a few that don’t work at all to help retain the tool. A lot of those hex shanks are also meant to be used with a magnetic driver that again does the retention well enough to hold the tool in use and still be removed and replaced by hand. I have dozens of hex shank tool tips and either use them directly in the drill chuck or with that separate magnetic driver in the chuck when I need to change to various tips often enough to make it worthwhile to use that set up. But the inconsistent sizes that started this thread sure seems to indicate poor quality control for the forging dies and finished product. Building down to meet a very low price point doesn’t work for retaining repeat customers either.

[Robert Atkinson 2Participant @robertatkinson2]

A loose fitting square or hex connection reduces the effective contact area under load (torque). This increases the stress and thus increased wear and probability of failure.
That’s apart from location issues and perfomance of the tool combination.

Robert.

[PeteParticipant @pete41194]

Of course that’s true Robert, I’m not stupid. But EVERY square drive mechanics tool including Snap On’s best use that spring loaded ball for socket retention. So obviously there’s a tolerance to keep the square slightly under size to meet that slip fit requirement, but not too far under. The same would hold true for hex drive tool tips that are magnetically held in the driver.

[Bill PhinnParticipant @billphinn90025]

Thanks for the feedback, everyone.

It was, as Michael’s post anticipates, the ease of detachability of sockets that first suggested something wasn’t quite right, though the four ends aren’t equally bad, possibly because of the different strengths of the springs behind the ball bearings. The short end of the 1/4” one is the worst: put an extension and a deep socket on this and they will drop off merely under gravity.

The 3/8” short end doesn’t drop sockets so easily but the degree of “backlash”of the square drive within a socket is disturbing. Who needs a wobble bar? Just make ordinary square drives undersized. Maybe that’s their logic.

Essentially for the reasons Robert gives, I’ll be returning these.

It’s notable that 1/4” and 3/8” offset (or L) handles aren’t nearly so common as 1/2” and 3/4” versions. Not sure why.

[Neil AParticipant @neila]

I’ve just had another read of BS 4006 on square drive sockets. They do state within that standard:

“The retaining device shall be positively fitted so as to prevent unintentional detachment of the socket”.

There is also a table giving the minimum detachment force (not including the weight of the socket or component).

1/4 drive 9N min. 3/8 drive 18N min.

I only include this for completeness, it’s irritating when things don’t perform as they should. The 1/4 drive parts that I bought from Halfords have worked just fine, never had a socket or extension fall off.

Neil

[Bill PhinnParticipant @billphinn90025]

Thank you for both lots of information, Neil. Good to have it.

[Neil LickfoldParticipant @neillickfold44316]

I measured a couple of hex bits. One was 0.25inches and the other 0.249 inches. More than 6.3mm and equal to 6.35mm. Clearly most of that set you meadired is junk. The brand mine came from is called Jonesway. No idea where made.

Neil

[SillyOldDufferModerator @sillyoldduffer]

Is this an expectation management problem?

Bill hasn’t said where his set came from or how much it cost.   The evidence suggests these are low-end countersinks of the type bought by DIY woodworkers.  Cheap, with a high-risk they will too cheap for serious metal-work.  No tears please if a set of 3-bits costing under £4 bought randomly off the internet turns out to be nasty!   The purchaser took a risk, and the product failed to meet his expectations.

The expectation that hex-ended tools must be sized to a standard is also false.   As far as I know, there is no legal requirement for these tools to be made to an ISO, BS, JIS or any other standard.   These standards only apply if the seller claims the product is made to meet them.  Did the supplier claim that: I bet not.

Trading Standards are fairly clear on who is responsible when purchasing goes wrong.    Organisations are expected to have a competent person in charge of purchases:  in a case like this it would be his fault if he bought an item without checking it met the standards required by his firm.   Consumers are better protected by law in that they aren’t expected to be competent.  Refund or replace if the product doesn’t meet their ‘reasonable’ requirements.   If the buyer or seller don’t agree on what’s meant by reasonable, off to arbitration or the courts.   In practice, at least in the UK, most sellers replace or refund without making a fuss.    Though it mostly works reasonably well, the system is imperfect.  Model Engineers are a case in point:  we’re a customer group with some competences who buy as consumers.  Having a few competences is a good start, but there’s more to competent purchasing than knowing a few reliable brand-names and assuming stuff.   For example, a pro-buyer has to know when it’s necessary for him to insist on a specification like ISO1173.   A Model engineer might assume incorrectly that was part of the deal: nope!

I notice Bill has done bought a tool-set with a specification!  His Gühring Set has a DIN number on it, in the blur bottom left:

None of this confusion is new, certainly not a sign of the times. My memory of youthful tool buying is there was a lot of dreadful tat about.  The Romans advised Caveat Emptor, and we Brits know not to buy a pig in a poke, because that might let the cat out of the bag!

Although honest trading is clearly most effective, there’s always a percentage of shady buyers and sellers who fink sharp practice is clever.   One clue we might be dealing with an opportunist is him offering items that are unreasonably cheap or, just as alarming, with a very high asking price.   Plenty of folk are fooled by ‘reassuringly expensive’!  It’s not easy, and we are lucky to have a Nanny State looking after us.

Professional engineers do their best to dodge buying uncertainty by setting standards because specifications can be tested objectively.   Purchases based on cost, brand-name, or previous experience can all be a con!    Unfortunately purchasing to specification isn’t easy, and it tends to be pricey.   I don’t have a big budget, and Model Engineers famously have very deep pockets and extraordinarily short arms.

What do I do myself?   Mostly I buy mid-range tooling from reputable UK hobby suppliers, relying on their expertise to avoid too cheap, and protected financially by UK consumer law.   ArcEuro do particularly well in this space, but I don’t expect top industrial tooling at rock bottom prices from them.   Ditto Tracy Tools, for taps, dies, and drills.  Others too.   They provide good value for money in my lightly loaded workshop, but sometimes a job makes it necessary for me to go upmarket.  I occasionally take a punt on ebay, so far without being sent rubbish.   The worst tools I’ve ever bought all came from street markets and exhibitions.   Consumer protection drops when the buyer actually sees the item:  then we are held much more responsible for our decisions.   If you buy in person, take extra care.   Distance buying is safer.

My buying strategy turns out to have been excellent for bad reasons.   Two years ago my mother’s failing health dropped my time for workshop fun by about 75%.   Over the last 7 months I’ve been too ill myself to use the workshop at all, and the problem is ongoing.   A tiny consolation is that I didn’t spend a fortune on the best tooling.  Even better, I’ve told my children not to worry about the value of the workshop when I die.  If it suits them to dump the whole lot in a skip, they can.  Had I invested in an expensively tooled-up workshop, it suffering that fate would be heartbreaking.

Do loose fitting hex shafts matter?  Not much in a basic DIY toolbox, perhaps only used once in a blue moon by a youngster to put up wooden shelves.   Same tools much less satisfactory when lots of countersinking needs to be done, and especially so in metal.   Robert points out that loose fitting hex shafts tend to chew up the driver, a quick way of wearing a good tool out.   Curiously all of my metal-working countersink cutters have round shafts and I don’t care what diameter their shafts are!

Dave

 

 

 

[Bill PhinnParticipant @billphinn90025]

I’m not sure whether it should be thought of as an expectation management issue, Dave, or rather a production management issue. Most aspects of the production management appear to have been got right; they’ve just fallen down on one critical dimension. Spoiling the ship for a ha’p’orth of tar, you might call it.

I like to think I exercise discretion when buying goods, and don’t have unreasonable expectations of them when I take into account their price, description et al.  The countersinks were bought from Garrison Dales. They have their branding, and are sold alongside other countersinks of various brands the majority of which aren’t described as conforming to any declared standard.

The lack of mention of a standard in the item description wasn’t a deterrent to me, as it clearly isn’t to many others of us who shop for tools of a similar kind. Arceurotrade sell two sets of unbranded countersinks. Neither is claimed to meet an established standard. And yet, judging by the levels of satisfaction with these sets I’ve seen expressed here and elsewhere, I suspect they meet the expectations of most, possibly all, users.

I’ve bought many tools over the years that don’t claim to meet any recognised standard, and they’ve largely been fine. Some of the stuff I’ve bought in the past that is the same brand as the offset handles – “Sourcing Map” – has far exceeded my expectations in terms of its quality and fitness for purpose.

So I’m not sure it’s an expectations issue unless expecting things not to have dimensions outside of the standard parameters by approximately 150%, as is the case with the 3/8” L handle, is unreasonable, and tools that are this far away from standard can still legitimately be claimed to be “of satisfactory quality”, when you bear in mind the undesirable knock-on effects of their quality on the other tools they couple with and on the execution of consistently competent work.

[JasonBModerator @jasonb]

Just to point out the ARC ones don’t have a Hex shank so as that is the one failing aspect that you mention of your set then ARC customers won’t be complaining about that. Also ARC set almost double the price though still a lot less than a similar Guhring set.

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