Question for the European and Australian members (any non-American)

[Crazyraceguy]

As an American who is stuck in the Imperial/Fractional measuring system, I wonder about drive sizes?
Square drives for ratchets/sockets 1/4"- 3/8"- 1/2" and then Hex drives like impact drivers 1/4" hex....even Centrotec. It has that stabilizing feature, but the underlying drive is still 1/4" hex.
WHY? I understand the Brits, they are mired in the mix of Metric and Imperial, so they use the most common.
The rest of the world though? Some of you guys probably don't even have fractional sockets or wrenches, since you never encounter "American" fasteners, so why would the drive of your tools not be metric too?
6mm, maybe 9mm, and 12mm would seem to be equivalent? Why not?
Is it really just "because it's always been that way" so changing would make a lot of old stuff obsolete? or require adapters?
Router bits seem to be in this too, at least slightly. 6mm, 8mm, and 12mm are out there, but don't most of the UK still use 1/4" and 1/2".
We can get some 8mm shank bits here, I suppose because of the mid-size? but 6mm or 12mm are virtually impossible to get. I assume because of confusion? Some dummy would put them into a fractional sized collet and have a catastrophe....either ruining a collet from overtightening its ability to compress, or throwing a bit across the room (or worse)

 

[luvmytoolz]

As Aussie's we're very accustomed to mixing imperial and metric. Router bits supplied to OZ via Asia are usually all imperial. If they're from the EU quite often they're oddball sizes like 8mm/12mm, which make it really hard to find cutters for, unless you get them from US and/or EU.

Funnily enough CNC cutters from Asia are often metric. 6/8/12mm shank, 2/3/4/5/6mm diameter cutters, etc.

For marking out and planning jobs it's generally always in metric for ease for most people I know, but when ordering or describing materials we'll often mix metric with imperial, like an 8' x 4' x 10mm sheet, or my personal favourite a 2.4 x 1.2 x 1/2" sheet of MDF, or an 8' 90 x 45 stud, etc.

We do find some aspects of the way the US uses measurements as strange, like 1/32" for timber, 4/4, 8/4, etc, we'd just call them 1"/2" or 25/50mm.

As for sockets and such, if it's bolts from EU or Asia, I find most nowadays are metric, but all plumbing even now and a lot of car related stuff are still all imperial sizes, so we need metric and imperial sockets and wrenches. Unless it's a very old bit gear I rarely come across any hex head bolts that are imperial, pretty much all in recent years is metric. Even the modern Nitto air fittings on everything are still a 1/4" BSP thread!

 

[Mini Me]

Drive sizes such as socket drives and 1/4 drive are overwhelmingly imperial and I think that is because those sizes are a world wide standard by default. Europe the world leader in metric still uses imperial in some instances such as road wheel sizes for cars and trucks which seems a bit weird as the tyre sizes are metric. In Oz we have mostly converted but as pointed out pipe & air fittings, television screens and the ones I find impossible to change to are air pressure and if someone asks me for my height, I haven't got a clue what it is in metric, weird I know. For all its faults I would not go back to tons, yards, acres, fractions are a nightmare, and just about every imperial measurement of anything.

 

[mino]

These are all "internal" tool standards so there was never the need to change these as they do not interfere with the "external" metric system in any way.

Funny thing is that for hex bits, there is a 8 mm standard for uses where 1/4" was too small and so metric 8 mm was chosen. In a way, this is also how 8 mm is so prevalent in small routers while 12.7 mm is still very common alongside 12 mm while the "traditional" 1/4" space is mostly taken over by 8mm. 6 mm being too weak and so dedicated to specialist trim routers only.

Personally, I do not like the 6mm versus 1/4" duality and especially the 12mm versus 1/2" duality. In both cases the "imperial" standard is about 40% stronger on the shaft and thus superior in practice.

Also the 1/8" versus 3 mm is just stupid. These are too easy to mix up for no benefit, so 3 mm it is.

8 mm bits, on the other hand, make a lot of sense since there was no pre-existing imperial "middle" standard around. 5/16" being too uncommon to matter.

ADD:
I have never in my life come across non-metric screws/bolts etc. So no need for imperial heads on wrenches etc. Even if tubing is imperial (actually, more like old English standards) all the nuts are using metric sizes.

I think the universal rule is:
- is it easy to swap/change and/or needed for good inteoperability => go ahead to metric
- is it hard (building plumbing etc.) to change and/or ir not needed to be interoperable => imperial is used alongside or even exclusively and no one bothers

I guess this must be weird to the US folk as they tend to take this politically. For us this was never political, so what was practical/good in the "old" system was retained and what was beneficial/easy to switch was switched.

Besides. Many people forget there is no "Imperial" anymore as the multiple (each Empire having its own) "inches, yards, etc." were abolished with a "metric inch" taking over starting in the 1960s. At that point the biggest benefit of Metric - international standardisation - was bestowed upon the "imperial" systems as well. Addressing a lot of the issues of the old systems in the process ... and making the switch less of a need.

 

[Crazyraceguy]

Yeah [member=61254]mino[/member] the "imperial" thing is a bit misleading, but many people understand the term. That's why I put the fractional thing in there too. You almost never see metric numbers expressed as fractions. It's not 1/2 a millimeter, that would be .5

I get the whole bit about sticking with the legacy thing, but then in some cases they ignore that and change the standard.
I like 8mm myself. It's considerably stiffer/stronger than 1/4" but not as intense as 1/2" for smaller cutters.
I have always been in favor of 1/2", except for the small trimmer type bits.
The OF1010 and MFK700 have gotten me into the 8mm

Mixing measurements is just weird though. It would drive me nuts [scared]
It's funny enough when someone refers to construction wood (studs) as 4 by 2. To us that's a 2 by 4 by whatever length.
Sheet goods are always width then length then thickness. "Length" being grain direction. It is confusing to new guys that there is a difference between a 4 x 8 and an 8 x 4. Since we do occasionally work with veneers and HPL in a cross-grain sheet, it does make sense to have an un-spoken standard.
Any time we write out cut-lists, it is done that way.
Metric measurements have crept into nearly everything, slowly so people don't notice. It has been a tool of shrinkflation in recent years. Things that used to be sold in quart jars/cans became liter, smaller but with the confusion, it worked....same price of course.

 

[woodferret]

Funnily enough CNC cutters from Asia are often metric. 6/8/12mm shank, 2/3/4/5/6mm diameter cutters, etc.

Construction stuff like 1/4 drivers and router bits is a legacy from US bases and restoration in the area after WWII.  A lot of construction work was based off knowledge interchange with US bases - Okinawa being a stark example of how housing changed completely.  Endmills, not having to be compatible with standard units (and China having switched over to SI in 1959, HK in 1976, Macau in 1992) that's a very strong force for that specific segment of manufacturing industry in the area to be just metric.

But it's hard to overcome the fact that day-day stuff is heavily influenced by the boatload of US bases in the asia pacific.

 

[MikeGE]

Metric measurements have crept into nearly everything, slowly so people don't notice. It has been a tool of shrinkflation in recent years. Things that used to be sold in quart jars/cans became liter, smaller but with the confusion, it worked....same price of course.

I hesitate to comment, since the title of your thread excludes Americans, even though I live in Europe.  However, just in case you didn't know, a liter has more volume than a quart, so it's not smaller.  One liter is about 1.06 quarts.

 

[Mini Me]

Yeah [member=61254]mino[/member] the "imperial" thing is a bit misleading, but many people understand the term. That's why I put the fractional thing in there too. You almost never see metric numbers expressed as fractions. It's not 1/2 a millimeter, that would be .5

If you asked an Australian about a fractional size he would look at you and wonder what drugs you were on and see if you had a better supplier than him. I had never heard the term applied to a measurement until I started reading US  WW forums. I have made the point here and elsewhere that the US is converting by osmosis due to having to interact with the rest of the world especially in manufacturing and suppliers only making to metric standards.

 

[luvmytoolz]

I didn't want to bring the whole "fractions" thing up! Shudder at the thought!

 

[wpz]

I have never in my life come across non-metric screws/bolts etc. So no need for imperial heads on wrenches etc. Even if tubing is imperial (actually, more like old English standards) all the nuts are using metric sizes.

Hi [member=61254]mino[/member] 

What about the screw threads on camera stands, microphone stands, laser levels, lights etc... those are imperial aren't they?
For instance the SYSROCK and SYSLITE have imperial threads in the bottom so you can mount them on a stand or on things like this:https://www.festool.com/accessory/499814---ma-kal#Overview

wpz

 

[mino]

Construction stuff like 1/4 drivers and router bits is a legacy from US bases and restoration in the area after WWII.  A lot of construction work was based off knowledge interchange with US bases - Okinawa being a stark example of how housing changed completely.  Endmills, not having to be compatible with standard units (and China having switched over to SI in 1959, HK in 1976, Macau in 1992) that's a very strong force for that specific segment of manufacturing industry in the area to be just metric.

But it's hard to overcome the fact that day-day stuff is heavily influenced by the boatload of US bases in the asia pacific.

TLDR:
You are thinking too much of the US (military) and too little of the British Empire (economy). Especially in Asia.

---
The Brits are no more, but the Global prevalence of *standard* Imperial measures one of their positive legacies. It has little to do with the US, except the US never saw the need to change this. Nort did the Germans, the Chinese or the Japanese. For that matter. As I mentioned. The rest of the World, possibly with the exception of the French and the Germans in the 1870s, never saw the SI system as something political "to go against the Empire".

It was and is a pure practical play that a fully interoperable (as in nuclear energy to weights) unit system based is superior in efficiency for anything serious. That we use it for things where pretty much any measure will do - like woodworking - as just a fall-off from that. With wrenches and some other things, the impact of changing (really immense) was simply bigger then the benefit (as in none in practice) so not even the French went for it.

If the Arabs, when they re-exported Mathematics to the "West" used a base-12 system, the only thing different would be that the SI system would be a base-12 with 0123456789ab digits.

But it would still be fundamentally the same. SI is built upon the rules of Nature and their relations. Not some political whim of a guy or a gal on who has the bigger ... This is unlike with the Imperial system(s) where the bigger empire won the trade wars through bigger and more "boats" and so *their* system is now called The Imperial system. Everyone long forgotted about the imperial systems of the lesser empires ...

---
The British Empire was a true global thing, way before "globalisation" existed as a word. And, most importantly, they were the technological leader and the tooling powerhouse throughout the 19th century up until WW1. The US was just a small player in the British trade system, when these standards came to be. So even those by US-based inventors were spread out by the British (system) around the world.

Over here, we never ever had any US economic "assistance" or any US military presence to speak off. Yet our local toolmakers were making 1/2" wrenches. Cause they were making them well before WW2, possibly before WW1, as a competition to the imported "English" tools ..

 

[mino]

I have never in my life come across non-metric screws/bolts etc. So no need for imperial heads on wrenches etc. Even if tubing is imperial (actually, more like old English standards) all the nuts are using metric sizes.

Hi [member=61254]mino[/member] 

What about the screw threads on camera stands, microphone stands, laser levels, lights etc... those are imperial aren't they?
For instance the SYSROCK and SYSLITE have imperial threads in the bottom so you can mount them on a stand or on things like this:https://www.festool.com/accessory/499814---ma-kal#Overview

wpz

When I mentioned nuts I meant "nut heads". That was not by accident. Even when these things often have "american" (as we tend to call it these days) threads, the newer interoperable kit tends to mix it with metric screw heads sizes, if there is a hex nut at all. At least from what I see.

Plus, frankly, most stuff I come across is the M8 standard, not 1/4". Possibly - like with the bits - that M8 is stronger while still not too-big and with easy to source thread adapters for the smaller kit using 1/4".

Meaning, I do not believe M8 is comming online over 1/4" courtesy of it being metric. It is comming courtesy of being more suitable for the heavier equipment while small-enough for the small stuff.

Again this is the case that what was easy to have metric, was done so, what was hard (interoperability) was kept chugging along. No ideology involved.

 

[six-point socket II]

Hazet is the only professional brand I can think of right now that does use a metric equivalent designation as well as the standard imperial designation for drive sizes on hand tools.

Example:https://www.hazet.de/de/produkte/ha...-einsatz/516/steckschluesseleinsatz-sechskant

6.3 - 1/4"
10 - 3/8"
12.5 - 1/2"
20 - 3/4"
25 - 1"

However people are absolutely used to and familiar with imperial drive sizes, just as they are to imperial sizes/designation for other products like pipe diameters, tripods, ...

Kind regards,
Oliver

 

[mino]

Mixing measurements is just weird though. It would drive me nuts [scared]

Someone who first came across fractional on this forum. It is not really a problem - the metric inch thing uses a sane decimal value, so reading is fine. Though would not do mix these on one project.

Here is my "thought" process:
1" => directly think 25.4 mm
1/2" => directly think 12.7 mm
1/4" => directly think 6.35 mm
random/random => pull out a calculator * 25.4, go on from there

beams:
4x2 => think (25*4) x (25x2) => 10 x 5 (in centimeters)
  => I do not bother with the .4 fraction as a 4x2 is exclusively for raw wood with it being the "wet" size ... so a 2x4 can be as small as 3.5" x 1.7" anyway ...
For reference, the common sizes sold here are 10x10 (100x100mm), 12x10, 8x8 etc., basically a "unit increment" of 20mm is used for the sales sizes of beams. For softwood boards it is usually 50 mm thick and 50 mm increments in width (so 5x20, 5x25, 5x30) and raw hardwood is usually ~30 mm (so one can plane off a 20mm plank) or ~50 mm (one can plane a 40mm-ish part off it).

precision talks:
0.1" => calculate 25.4/10 => 2.54 mm
0.01" => calculate 25.4/100 => 0.25 mm
0.001" => calculate 25.4/1000 => 0.025 mm

All that is actually easier than thinking in the LR32 units system where all units are 32mm but they do not have the " symbol to denote them and so the actuall dimensions are still in mm. Argh!

Overall, I think is is easier "thinking" in millimeters or centimeters and using inches where needed - the multiplication action is easier than division for the brain.

Then for me, I never was bothered with the fractional thing. If the fractions are sane, like up to /4 or when bases are same => fine. Rest just gets converted to decimal, then add/subtract etc. That said, I am physicist/chemist by field of study ... so probably not a representative sample.

Still think that for a "metric & decimal" person to use inches is easier than for a "fractional" person to be asked to use millimeters all of a sudden.

Which brings me, thanks to this mental excercise I have just decided on a t-unit system based on the 32 mm "unit". That should solve the "unwieldy" multiples-of-32 "things" and the eternal thoughts if to make something 580 mm or 570 mm. Erm.

"full" unit sizes:
      30t      896 mm (width for dual 600x400 Euro-boxes with slides) => 900 with movement buffer
      21t      672 mm (depth of dual-side systainer with "tetris" slides)
      19t      608 mm (depth of 600x400 Euro-boxes with slides)
      18t      576 mm (depth of clothes cabinets)
      16t      480 mm (depth of MAXI systainers with 450mm slides)
      15t      448 mm (cabinet width for single 600x400 Euro-boxes, without slides) => 450 with movement buffer
      10t      320 mm (depth of one-deep cloth cabinets, kitchen cabinets)
        6t      192 mm (depth of one-deep kitchen cabinets)
        3t        96 mm (MFT)
        2t        64 mm (my planned MFT spacing)
        1t        32 mm (LR32)

"standard" fractions (unit is 1/8 of t, written as "/8")
9.5/8 = 1.1875t = 38 mm (thick kitchen desk boards)
6.5/8 = 0.8125t = 26 mm (thin kitchen desk boards)
  6/8 = 0.75t  = 24 mm
5.5/8 = 0.6875t = 22 mm (thick chipboard)
  5/8 = 0.625t  = 20 mm
4.5/8 = 0.5625t = 18 mm (standard chipboard, standard ply)
  4/8 = 0.5t    = 16 mm (2/8 back panel with 2/8 buffer)
  3/8 = 0.375t  = 12 mm (thin chipboard, thin ply)
  2/8 = 0.25t  =  8 mm (ply back panel)
  1/8 = 0.125t  =  4 mm (facing ply)


Muh. Will see how it goes. Looks I will standardise on the "whole" /8 materials. Thinking about it. Possibly excepting the 4.5/8 chipboard and ply which are too ubiquitous.
[eek]

 

[mino]

Hazet is the only professional brand I can think of right now that does use a metric equivalent designation as well as the standard imperial designation for drive sizes on hand tools.

Example:https://www.hazet.de/de/produkte/ha...-einsatz/516/steckschluesseleinsatz-sechskant

6.3 - 1/4"
10 - 3/8"
12.5 - 1/2"
20 - 3/4"
25 - 1"

However people are absolutely used to and familiar with imperial drive sizes, just as they are to imperial sizes/designation for other products like pipe diameters, tripods, ...

Kind regards,
Oliver

Weird, if I was reading that while buying, NOW I would be confused. 1/2 is not 12.5 mm and 3/4 is not 20 mm. The 20 mm case is an awfull lot away - 0.95 mm is ridicilously much at a 20-ish mm square.

I would immediately start searching if they are using some "other" standard and be concerned with compatibility with "native" 1/2" (12.7) wrenches.

Or, more likely, I would implicitly avoid buying from them unless a whole set or having them in hand and being able to measure the actual sizes. Not worth the risk.

I have quality wrenches where 0.2-0.3 mm is all the space there between the wrench square and the socket. I have also seen - then presumed just low quality - wrenches where the sockets wiggle like crazy ... these could be the "12.5 mm" ones ... but cannot imagine a 20 mm wrench working. It should not even fit into any of the higher quality sockets!

All considered, I think that is just a lazy non-technical sales guy writing garbage on their web page. Cannot imagine otherwise.

EDIT:
Checked and DIN3124 indeed uses 6.3 mm for "1/4" and 12.5 mm for 1/2" ... there is some tollerance, so something tells me one (metric) is the wrench size while the "other" (imperial) is the socket size. Will go ahead and measure my kit today.

Still cannot see the 20 mm making sense for 3/4" wrenches.

 

[six-point socket II]

Just keep in mind they only use this for drive sizes (Antrieb) , not "output" sizes (Abtrieb)/ wrench or socket sizes.

Kind regards,
Oliver

 

[mino]

Checked.

All my quality ones - from 10 to 40yrs old, Czech or "German" but from Chinese OEM - are 6.29-6.32 and 12.68-12.75 respectively for the wrench side.
The sockets are 6.40-ish and 12.85-ish respectively.

I cannot see how 12.5 on the wrench side would work well with these sockets. It would be wobbly like the chinesium set I got which is all over the place with wrench at 6.10-ish and definitely non-square at that.

Only thing explaining this can be the DIN standard in question is not followed by any self-respecting manufacturer. So it shows up on the wobbly hobby stuff and the likes. My Chinesium set agrees with that scenario.

 

[Crazyraceguy]

[member=70363]MikeGE[/member] sorry, I wasn't trying to exclude anyone. I was just looking for a perspective from people who have a different cultural experience. (Which you apparently do, while still being an American)

Yeah [member=61254]mino[/member] the "imperial" thing is a bit misleading, but many people understand the term. That's why I put the fractional thing in there too. You almost never see metric numbers expressed as fractions. It's not 1/2 a millimeter, that would be .5

If you asked an Australian about a fractional size he would look at you and wonder what drugs you were on and see if you had a better supplier than him. I had never heard the term applied to a measurement until I started reading US  WW forums. I have made the point here and elsewhere that the US is converting by osmosis due to having to interact with the rest of the world especially in manufacturing and suppliers only making to metric standards.

Don't you guys have ratchets and sockets that have 1/4", 3/8", or 1/2" square drive?

None of this is a problem for me. I have been thinking in decimal equivalent of all of these dimensions for years. It started in a machine shop class in vocational school and has been very handy ever since.
I don't do so well with larger metric dimensions. Below 1" is easy and up to about 100mm is ok, beyond that, I have to think about it. (or hit the calculator)

It just seemed odd to me that the rest of the world, who all embrace the Metric system, still stick with a few legacy things. 1/4"-20 threads and socket drives especially.

 

[MikeGE]

Don't you guys have ratchets and sockets that have 1/4", 3/8", or 1/2" square drive?

The metric socket sets in German hardware stores have 1/4", 3/8", and 1/2" square drives.  Iron water pipe and fitting sizes are 1/2", 3/4", and 1" NPT.  Plastic hub caps to dress up steel rims for cars are 15" and 16" (maybe 14" also).

The first German hardware store I've seen to stock SAE hardware is the Hornbach in Weiterstadt.  I don't know what prompted this, but last year I noticed a large area with wide selection of UNC and UNF hardware ranging from 1/4" to 7/16".

Edit: I just noticed that Oliver already mentioned the socket drives and pipes.

 

[Crazyraceguy]

[member=70363]MikeGE[/member] That brings up an even sillier thing. SAE hardware sizes

1/4" bolts and nuts have 7/16" hex
5/16" .........................1/2"
3/8"...........................9/16"
7/16...........................5/8"(sort of)
1/2"............................3/4

They all use the same size hex on the nut and bolt, when you use Nylon lock nuts, but 7/16" has a nasty trick.
I'm sure the metric guys will lose it over this one. The standard size for a non-locking 7/16" nut is not the same as the bolt. It's actually 11/16", not 5/8" None of the rest are like this.....why?