SCREWS! A brief history of screw drive systems used in the UK

in the next video I'm going to take you through all the different types of screws that I use and what I take out to pretty much every job but before we go down that route I wanted to explain the different drive types that you're likely to run into and what I've personally settled on for pretty much all of my screws I have folks welcome back to the workshop forget about politics religion brexit whatever if you want to start an argument in the maker community just ask a bunch of people what their favorite types of screws are as far as I'm concerned from a UK perspective there's only really two types of screws that I ever use and I can assure you they're not Philips and for that to make a bit more sense we need to have a little history lesson about screws there are a lot of different screw drive systems out there but to keep things simple I'm just going to talk about the seven most common ones that you're likely to run into so pretty much from when screw threads have first existed people have thought well how are you going to turn the head of the screw and one of the most logical things to do is just cut a slot in the top of the screw head and this green little bit here is my pretend kind of screwdriver thing and if you imagine when you turn your screwdriver what it effectively does it puts force onto the sides of the slot around here and around here so you've basically got two points of contact on the screw head now obviously if you using a slotted head screw you should try and use a screw driver that actually fits a slot properly and by having a screw driver that fits a slot properly you're basically extending the load distribution across here and across here so it gives you a bigger surface area that is acting on the actual slot but effectively it is basically just two points of contact here and here so the next logical step from there was to cut another slot perpendicularly a first slot to create a cross head screw the first big innovation of the 20th century came about all the way back in 1908 when Peter Robertson invented the Robertson Drive again this gives four points of contact or four points where the load of turning the screw is transferring over onto the screw head so in this case here here here and here the other big advantage of the Robertson though is that the screw driver bits themselves are slightly tapered so it means that you get quite a good transfer of force all the way around the screw head and you'll find if you try Robertson screws it feels like a really positive fit between the screw driver and the screw but you've still just got four points of force transfer the two big disadvantages with Robertson though is that they're not self centering and they're only used by a tiny fraction of people in the UK I'm not saying don't use them if it was a choice between Robertson or hex I would pick Robertson any day but for me personally I think better alternatives have been developed now then around thirty years later around 1934 the Philips screw head was born it was actually invented by a guy called John P Thompson but he sold his design on to Henry Phillips and the Phillips screw company was born again we've got four points of force transfer onto the head of the screw so here here here and here and the Phillips screws also had the advantage as well that there's a slight taper on the head of the screwdriver bit which means that there's a bit more flexibility in terms of using the same screwdriver for different size screws but we've still essentially just got four points the force transfer a couple of years after that in 1936 the hex head was developed by Bauer and shower T I'm gonna brush over that but the hex head does have the advantage that were now putting six points of contact on this screw head the hex head screws are still used today in flat pack furniture but really they're being overtaken by stalks no which will come to a little bit later on the next big development was then in 1962 when GKN screws and fasteners developed the posi drive system quasi drive look exactly like Phillips screws except we've got these little markings here at 45 degrees to the main cross and that's how you know it's a posi drive screw it's actually very different to a Phillips screw and the big difference is that in addition to the cross that you would have on a Phillips screw we've now got these extra four points of contact between the screw driver and the screw it's a bit misleading with having these little lines here those lines don't really do anything other than signify that it's a posi drive screw so if I just hide those out the road but we've got these little grooves in the corner here at 45 degrees to the main cross and of course what that means when you turn the screw driver we've now got points of contact here here here and here plus points a contact here here here and here so technically with the posi drive screw you've got eight points a force transfer now admittedly the force transfer on the little flutes around the middle of the screw have a very small surface area but it does make a significant difference and that's why posi drive screws are much less likely to come out then Phillips screws and then finally in 1967 the torques drive was invented by Kamkar Textron the torques drive only has six points of contacts and not as much as the posi drive but the big difference is that we've got those points of contact over a much bigger surface area so effectively when you're turning a torque screw you're getting a really high surface area of load transfer in six points around the screw head so even with six points the force transfer as opposed to the eight that a posi drive screw has it does mean that you can get much higher torque out of a torque screw funnily enough the disadvantage though is that a torque screwdriver bit isn't tapered in the same way that a posi drive bit is tapered so whereas a posi two or pset2 screwdriver bit will work with a whole range of screws from tiny little screws up to really quite big screws [Music] with torques you have to be much more particular to make sure you've got the correct size bit for the screw that you're using because of the self centering nature of posi drive bits as well you find that once a screw is on the end of the bit it's much less likely to fall off the bit while you're moving the screw around in my experience that's not the case with torque screws and that can cause some problems in some situations [Music] so for me I prefer to use posi Drive for the vast majority of situations there by far the most common screw that you're likely to run into in Europe and they offer a great balance between self centering bit grip and torque a standard PZ 2 bit will fit pretty much everything that I use on a daily basis from little cabinet hinge screws all the way through the bigger screws that are used for attaching big things on the walls if I'm doing a lot of fastening that needs a higher level of torque then Torx screws are awesome but in all honesty for the sort of work that I do in 99% of situations Posey Drive works absolutely fine they grip the screw head really well as long as you use in good quality screws and good quality bits and for me if you're using them in an impact driver they never come out one important thing to remember with posi Drive screws is that a Phillips bit will fit in a posi Drive screw but you can't use a posi drive bit in a Phillips screw the little flutes on a posi drive bit just don't engage properly with the head of a Phillips screw and hence my general hatred of Phillips screws since it means hunting around for an obsolete screwdriver of course there are situations where you're going to run into other Drive types especially hex headed bolts for bigger fixings hex sockets on confirm at screws and that even sometimes use Robertson Drive for my pocket screws you use whatever type of screw you want to use that's easily available in your part of the world all I would say is if you're building something for a customer that might need to be taken apart or adjusted at a later date then do try and use screws that will work with screwdrivers that the customer is likely to have in their house just because you have a full set of talks tamper resistant screwdrivers doesn't mean your customer does and if you're in the UK and you have to buy just one good screwdriver make it a - with all of that out the road next time I'm going to take you through all of the screws that I use on a daily basis that I've carry around with me all the time so if you knew the channel don't forget to hit subscribe for now take care folks and I shall see you next time bye [Applause] you [Music]

Channel: Gosforth Handyman

Views: 67,526

Rating: 4.9161968 out of 5

Keywords: screw types, types of screw, pozidriv, pozidrive, torx screw, phillips screw, history of screws, best type of screw, diy tips, home improvement, do it yourself, woodworking, screwdriver, pz2, pozidriv vs phillips, pozidrive screw, woodscrew, wood screws, torx vs, torx vs robertson, torx vs philips

Id: qz4agkBBFUo

Length: 11min 6sec (666 seconds)

Published: Wed Jan 22 2020