Some years ago, Supascrews were introduced, and mixed packs were sold, complete with cross head driver. Yellow plastic tray, with clear flip up lid. Anyway, the name seemed to disappear, although Twinqwik surfaced, and seemed to be the same.
Having stocks of a whole range of sizes (and several drivers), I want to top up a few, but neither name seems common now. Does anyone know whether Pozi heads are the same? I don't want to buy, then find the head of the drive is similar, but not quite the same.
As with Goldscrews etc they're just trade names. Twinquick sounds like a twinthread screw. In theory twinthreads are easier to start and drive, which makes them popular with anyone using a lot on a daily basis while single threads have a beefier thread which gives better purchase especially in softwood and MDF.
Pozi heads - the actual indentation on the screwhead, bits and screwdrivers come in 3 sizes.
Its sometimes possible to get away with using the wrong size, usually accompanied by a crunching noise, a slipped driver and possible swearing.
Exactly. There are only three sizes, you should be able to tell the size of the screwdriver bit at a glance. With a bit of practice you will be able to recognise the screw heads too. And it is normally immediately obvious if you have got the wrong one.
Incidentally, if you have much screwing to do, you might be impressed at how good cordless "impact drivers" are. This is one random example
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Note that it does not include the battery or charger. I actually have the 14.4 volt Makita, personally I would not consider any lower voltage than that.
You should buy the tougher bits made for impact drivers, but they are not all that expensive. The bits do wear out, but I find I damage screw heads less often with these than with a conventional drill/driver. The combination of power and controllability is really remarkable.
There is some price variation in screws. Trade people normally use the more expensive brands such as Spax or Screwfix Turbo Gold or Goldscrews. FWIW I normally use the cheapest (such as Quicksilver). Sometimes an impact driver will snap the head off.
Most woodscrews these days are Pozidrive, but a few specialist types come with Torx or hex (allen-key type) heads. The bits are not expensive.
Thanks all. Yes, I can easily tell the difference when actually looking at the screws, but was hoping to buy supplies online, where seeing the difference is not so easy. We were supposed to be going to B&Q today, but that has been cancelled (don't ask), and given that it is a 90+ mile round trip, I don't get there very often.
Supascrews were introduced by GKN at least 30 years ago (1980ish?), and I bought a fairly substantial supply, from 6 x 1/2 to 12 x 4, and have been using them ever since. GKN subsequently withdrew from that market. Back then, most ordinary wood screws were slot headed, not cross.
My question is not about the difference between Philips and Pozi, or the different sizes, but whether the GKN cross head is still standard, or whether it was a one off unique to GKN, and now long gone. The screws were around for years after GKN withdrew from the market, but supplies have now all but disappeared.
Most woodscrews on sale nowadays are pozidrive. In order to buy and use woodscrews in the future, you'll need to buy a pozidrive screwdriver. You'll most likely only need a number 2 as this fits all screw sizes up to 10 (4.5mm). No 1 fits mainly screws on electrical fittings etc while no 3 fits very large woodscrews or mainly pozi heads on things like M6 machine screws.
A number 2 pozi screwdriver on its own will cost a few quid at most.
(This assumes you have no interest in powered screwdrivers which all come with bits which are otherwise readily available for a few quid)
If you like, you can spend three times as much for a set including a no 3 which most likely you'll never use. Possibly in a nice case or wallet which simply take up space.
Armed with your number 2 pozi driver you can see if this fits the GKN screws.
Other than that, quite honestly the only reason I can think of why anyone would insist on matching screws bought 30 years ago was
a) if these screws were anodised a particular colour i.e as in Turbogold and it was necessary to match these when repairing a 30 year old item
b) it was a for a restoration job which had to be authentic in every respect - i.e usung original materials.
Given possible differences in colour it might not be possible to mix the GKN's with other screw where these will visible.
However given the prices of screws in places like Toolstatio nowadays, your foresight in stocking up thirty years ago at what seems like bargain prices at the time, might with hindsight have been rendered uneccessary.
This is far from uncommon as lots of independent DIY shops were closing up around 30 years ago and selling off stock on the cheap.
However nowadays by comparison the likes of Toolstation in particular are almost giving the same stuff away.
All 'cross head' screws are either pozi or philips. Most diy size screws are PZ2, except plasterboard screws which are often PH2. The smallest are PZ1. PZ0 & PZ3 aren't often seen on diy size screws.
PZ and PH are easily differentiated, PZ have corner bits in, PH don't.
Michael, thank you for a well thought out and comprehensive response.
It isn't so much that I stocked up as in duplicated boxes of the GKN screws, just that I acquired a wide range of sizes and lengths, all sharing the same driver. Yes, I could easily buy several Pozi drivers, but having two incompatible sets of anything is always a pain. Just having Philips and GKN is bad enough.
Anyway, I only really need one size topping up at present, and a box of
250 is a couple of pounds delivered, so I'll bite the bullet, and will report back as to whether or not they fit my GKN drivers.
Personally I would throw away all the Philips screws. OK I have some in my random jar of self tappers, but that is only in case I need an odd sized replacement. (There is also a Japanese sort of Phillips, typically found on cameras and electronics).
I think the odds are that the GKN will be Pozidrive. These have a "nick" in the corners of the socket and a matching "ridge" in the driver.
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Anyway, try a Pozi 2 driver as suggested elsewhere. Even if you don't have one, surely a neighbour has?
Practically everything from kitchen cabinets to electrical appliances has pozi screws these days.
I remember Supascrews coming out - I was still at work so yes, must have been about 30 years ago. Rather alarmingly, one claim was that they can tolerate up to 10 deg. of misalignment of the driver - we never managed to find the figure for Pozis.
I still have a couple of Pz 1 drivers from those days and they're v. useful at times, as is the Pz 3.
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