LordPsychon
Well-known member
Does anyone know why sockets come in 1/4", 3/8", 1/2" and 3/4" (most common drives)? Why no metric drives (10mm, 15mm, 20mm for example)? Why no 5/8" drive? Truthfully I am just curious.
Socket to me! Drives question.
- Thread starter LordPsychon
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Triple macs
Well-known member
5/8, 7/8 & 9/32 were all available in the 20's. Since they were patented by US companies, like Snap-on, drive sizes were fractional.
Kirbot
Well-known member
I actually have an old Cornwell 5/8" drive socket.
d.mcfarland
Well-known member
I think it's widely adopted and fully accepted. Much like the USA going metric.
Mechanical Noise
Well-known member
I'll bet it happened but market forces killed them off.
The situation is probably similar to the early days of disk record players. The major manufacturers settled on the standard 78 rpm disk but there were a few manufacturers who tried to lock customers into oddball formats. The odd formats quickly became orphans.
I don't see any particular incentive to metric drives even in metric countries. If the first drives are inch sizes then it makes sense to make competing products in compatible sizes.
An inch standard for drive tools in metric countries is similar to the 35 mm film standard in the US.
Oh man, you're kidding me. Really? This place just keeps getting better.
You're gonna love the answer. It's because an American company in the 1920s produced the first socket set which included sockets with square drives that, get this, "snapped on" to interchangeable handles.
Square drive tools actually predate Snap On. People have been making interchangeable bit drills using tapering square drives for centuries. And keep in mind, the metric system is fairly new.
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I have some Proto 5/8 stuff that is much newer than the 20's.
Oh goodness me..... The Metric system has been around since 1799......
Anyway, for the OP... I was curious about this once, and the best answer I got was
because the industrial revolution started in countries that used the imperial measurment
that was the starting point and what followed was probably just logic...
1/4" = 2/8"
3/8" = 3/8"
1/2" = 4/8"
3/4" = 6/8"
1.0" = 8/8"
Probably nothing more than that.
The oddball drive sizes didn't last becauseof that logic, and by the time all of the 200 odd countries of the world (with the exception
of Burma and the United states) decided to go sensibly metric it was too late for many
well established things to change... like tyres and socket drive sizes for example. Although
some have tried... and unsurprisingly failed.
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OP
LordPsychon
Well-known member
Early socket set drive sizes were 1/2" and up usually including 11/16" external drive pressed steel sockets. I've read of them going back as far as 1906.
Those days there were no standards to hex or square drive and if you wanted to make them in 37/64" drive go ahead.
That kind of locked you into a brand as no one else made a same size. Years wore on and a few better sellers sort of determined what drive style was going to have spare parts, be they in the brand of your set or another. The sets that got spares ( a set was more than a week's pay then ) survived and new mechanics bought those as they could. By the 1940's most really odd stuff was done, the 1960's sort of ended hex drive as a contender as 1/2' square was taking over the market.
This was in part to SO marketing plans of shop to shop sales and payment plans starting in the early 20's making these more accessible.
All the other makers cashed in on this as replacement parts could be any brand, just like it is today worldwide. The 1/4" drive size was made popular by being handy for radio/tv work and the 3/8" for aircraft and later car repairs. The 1/2 was too big in some models by the late 40's.
Those days there were no standards to hex or square drive and if you wanted to make them in 37/64" drive go ahead.
That kind of locked you into a brand as no one else made a same size. Years wore on and a few better sellers sort of determined what drive style was going to have spare parts, be they in the brand of your set or another. The sets that got spares ( a set was more than a week's pay then ) survived and new mechanics bought those as they could. By the 1940's most really odd stuff was done, the 1960's sort of ended hex drive as a contender as 1/2' square was taking over the market.
This was in part to SO marketing plans of shop to shop sales and payment plans starting in the early 20's making these more accessible.
All the other makers cashed in on this as replacement parts could be any brand, just like it is today worldwide. The 1/4" drive size was made popular by being handy for radio/tv work and the 3/8" for aircraft and later car repairs. The 1/2 was too big in some models by the late 40's.
This has got to be the most informative discussion forum on the internet, and I'm only exaggerating a little. I could, and do, burn hours here. I learn something in every thread.
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Dave455
Well-known member
Simple!
It's because the very first socket sets were made in the U.K. and the U.S. who used imperial measurements! (So did a lot of Europe back then too).
Many early Britool socket sets used a 7/16 hex drive, and they kept making the accessories for years!
Government contract tools sometimes have unusual size drives in an attempt to prevent pilfering. In the U.K. it's often 1/32 greater than standard, so you will see government sets in 9/32 instead of 1/4 and so on!
I believe the U.S. government did something similar, but with different sizes!
Blackhawk offerred different sizes too, there was quite a variety before the war (5/8 comes to mind). When they first offerred their really sleek modern tools post war (can't remember what they were called now) they were designed to do the job of both 3/8 drive and 1/2 drive. I think they were all 7/16 drive!
When I first encountered Facom tools their drive sizes were metric equivalents of 1/4, 3/8 and 1/2, so their sockets didn't fit well on anybody else's handles! They soon stopped thst nonsense! A few years back they tried introducing their CDX drive, which was a sort of square spline. Great idea, and retained some compatibility with existing drives, but I suspect doomed to failure like all these non standard things!
It's because the very first socket sets were made in the U.K. and the U.S. who used imperial measurements! (So did a lot of Europe back then too).
Many early Britool socket sets used a 7/16 hex drive, and they kept making the accessories for years!
Government contract tools sometimes have unusual size drives in an attempt to prevent pilfering. In the U.K. it's often 1/32 greater than standard, so you will see government sets in 9/32 instead of 1/4 and so on!
I believe the U.S. government did something similar, but with different sizes!
Blackhawk offerred different sizes too, there was quite a variety before the war (5/8 comes to mind). When they first offerred their really sleek modern tools post war (can't remember what they were called now) they were designed to do the job of both 3/8 drive and 1/2 drive. I think they were all 7/16 drive!
When I first encountered Facom tools their drive sizes were metric equivalents of 1/4, 3/8 and 1/2, so their sockets didn't fit well on anybody else's handles! They soon stopped thst nonsense! A few years back they tried introducing their CDX drive, which was a sort of square spline. Great idea, and retained some compatibility with existing drives, but I suspect doomed to failure like all these non standard things!
The UK adopted the metric system in 1965. Hell, the UK had 240 pennies to a pound in 1970.Oh goodness me..... The Metric system has been around since 1799......
Switching to metric isn't easy. Just imagine all the lathe screws, change gears, the stuff that makes stuff, inspects stuff, and the enginering drawings.