What are some oddball metric socket and wrench sizes?

[atikovi]

And what are they used for. I have an 11mm combo wrench that have only used on brake bleeders and a 5.5mm socket that I used years ago and don't remember what for. None of my sets came with 20mm sockets or wrenches although 19 and 21 are pretty common. What are 20's used on?

 

[egnorant]

I have used 4, 4.5, 5 and 5.5mm on some electronic stuff. My oddity is 6.3mm sockets! I have both deep and shallow in 6 point that is actually a 1/4" just labeled in metric.

Bruce

 

[wombat31x]

I have a 3.2mm combination spanner made by Stahlwille.

 

[Fedwrench]

I've never used a 20mm socket but, I've used a 20mm open end wrench on old GM Fuel filters, and some older GM ac lines to access the orifice tube.

5.5mm is a common trim screw size. GM & Ford also use that size of fastener to secure their AC actuators. I've always though the .5mm socket sizes were from someone refusing to use an SAE socket ending in 32nds.

People were mentioning 23mm recently as being needed for MAZDA lower ball joints

I think the metric sizes are simpler. Japanese stuff tends to use 10, 12, 14, 17mm, a lot whereas, GM attempts to mess the metric system up by using 8, 10, 13, 15, & 18mm

 

[anavrinIV]

My intercooler piping had t-bolt clamps with 11mm nuts. They may have actually been 7/16 but the rest of the car was metric and the difference is so small the 11mm worked perfectly.

20mm...never used one. I don't know that I have one.

I worked for a small OPE company that had a lot of 10mm fasteners with 16mm bolt heads. Haven't used that wrench since I left the company.

 

[wombat31x]

Basically there are three different metric standards

ANSI/ISO American National Standards Institute/International Standards Organization.Which is your US made stuff

DIN Deutsches Institut für Normung.Which is the German Industrial Standard

JIS Japanese Industrial Standards.

 

[hifi_hokie]

New Jeeps are basically held together with 18s.

 

[1950mercury]

I use my 20mm to keep my tool OCD in check. It keeps the 20mm peg on the Hanson tray company.

 

[General Geoff]

20.8mm spark plug socket (on the left)

It's the Japanese way of denoting 13/16"

 

[Tenex]

I used a 5.5mm the other day for removing the sensor on top of the camshaft synchronizer in my truck.

 

[John in OH]

My old VW bug (1968) had a lot of 11mm fasteners. In fact, the little tool kit that came with the car had an 11mm open end wrench included.

The 11mm size on a German car jives with wombat31x's table above for DIN standards.

 

[theoldwizard1]

23mm. I needed one the other day. Lucky I had a 23mm combination wrench, but i need to "double up" to get enough leverage (ball joint stud nut).

 

[rice rocket]

Basically there are three different metric standards

ANSI/ISO American National Standards Institute/International Standards Organization.Which is your US made stuff

DIN Deutsches Institut für Normung.Which is the German Industrial Standard

JIS Japanese Industrial Standards.

Nice, I've never seen it consolidated into one chart.

That said, I use a decent amount of 21mm on cars that should follow JIS, that's not on the chart; I assume that would be M15?


What standard does Aus follow?

 

[Cmjl67]

Jaguar X300 requires 17mm o2 socket - try finding one of those!!

I know i need to replace mine....at some point....so I've got crows foot wrenches and just ordered 17mm deep socket I'll cut a slot along but still know it will be pig of a job as the things are so far down

c

 

[Channing81]

My VW bus uses a lot of 11mm. I have an Italian Vespa that uses 6, 7, and 8 mm.

 

[wombat31x]

I think our dwindling car manufacturing industry uses the ISO metric standard but from what I have seen around here domestic construction uses whatever they have available i.e. the cheapest.Since I work in the rural industry I have to have every socket and spanner size made including SAE,Metric and Whitworth but still I get caught out with some oddball Chinese sizes not usually in the manufacturing but with bolts used to secure items into packing crates

 

[Al Borland]

I have a 3 mm Snap-on combo wrench I found in the street. About the length of a toothpick, and barely fits around a 1/8" drill bit. Haven't a clue what anyone would use it for, when I picked it up I thought it was a toy wrench.

 

[theoldwizard1]

People were mentioning 23mm recently as being needed for MAZDA lower ball joints

Yep ! Mazda6 and all Mercury Milan and first gen US Ford Fusion, so that is a fair number of vehicles !

 

[dnschmidt]

That's a nice chart but most American cars are polluted with 15mm and that size doesn't appear on any of the three standards. Where did that size come from.

 

[wombat31x]

Ha ha I never said the metric standards were law,I remember reading somewhere that the 15mm size came about to give better clearance for working with modern engines.I'd like to believe the reason for a bolt head being 15mm and the nut 16mm is so that you only need a single set of spanners to work with them,but I suspect it's a way for design engineers to leave a signature on their designs without actually signing it and to piss mechanics off..haha

I recently came across a Toyota Land Cruiser that had a 23mm rear diff bung they are normally 24mm but this one had been replaced I know it's not a genuine Toyota part and have no idea what the replacement plug was originally designed for.

 

[Gmonkee]

Torx and Etorx are taking a place too. I work on mostly imported type cars so the gamut of metric sizes all get used. My bag has up to 22mm at the ready and all see some use.

What I noted was each car uses fewer wrench sizes per job now than the cars s decade ago did. That is kind of nice. Less to recover st jobs end.

 

[T45]

Side note: Whatever happened to the euro/DIN evolving from 17/19 to 16/18? ...did that ever go anyplace or did it get stuck in limbo-land? something about smaller lighter hardware or some other reason (globalizing standards?)...anyone know??

 

[L.Cheapo]

My old VW bug (1968) had a lot of 11mm fasteners. In fact, the little tool kit that came with the car had an 11mm open end wrench included.

The 11mm size on a German car jives with wombat31x's table above for DIN standards.

IIRC, the brake line fittings are 11mm.

 

[Rico.]

To answer the question directly the most rarely used metric sizes are...

4.5mm, 6.5mm, 9mm, 20mm, 23mm, 25mm, 26mm, 28mm, 29mm, 31mm and 33mm

 

[ultgar]

I have a 3.2mm combination spanner made by Stahlwille.

I used to think 3.2mm was unusual & practically useless until I realized is was exactly 1/8" (well almost.... 0.126" vs 0.125").

SD

 

[John in OH]

Here is another table, very similar to wombat's table above, but does have a few slight differences. In particular, it address some of the larger sizes in a little more detail.



Note, the listing of the six most common sizes greater than 19mm.

I have encountered 9mm before, in an electrical application IIRC, and I recall, in the past, reading here on GJ references made by others to using 20mm on some Asian oil pan drain plug/s.

 

[Loscaldazar]

Subaru (japan) uses 21MM on a lot of their transmission drain plugs to keep idiots from draining the transmission and filling the engine oil (it's an actual problem when you take your Subaru to Jiffy Lube and such, they mistake the transmission oil pan for the engine oil pan). They eventually changed it to a T70 torx on the transmission and front differential, because how many people (even here) have one of those?

 

[atikovi]

They eventually changed it to a T70 torx on the transmission and front differential, because how many people (even here) have one of those?

I have an E24 socket. Wonder if anybody else has one of those and what they are used for? Used an E22 on Dodge suspension parts though.

 

[Kent_B]

They eventually changed it to a T70 torx on the transmission and front differential, because how many people (even here) have one of those?

I do have one of those, for that specific purpose. I've used it twice.

 

[General Geoff]

They eventually changed it to a T70 torx on the transmission and front differential, because how many people (even here) have one of those?

Have yet to use it, but I have it.

 

[2ndGearRubber]

Subaru (japan) uses 21MM on a lot of their transmission drain plugs to keep idiots from draining the transmission and filling the engine oil (it's an actual problem when you take your Subaru to Jiffy Lube and such, they mistake the transmission oil pan for the engine oil pan). They eventually changed it to a T70 torx on the transmission and front differential, because how many people (even here) have one of those?

I have 2 T70.

I have an E24 socket. Wonder if anybody else has one of those and what they are used for? Used an E22 on Dodge suspension parts though.

I have 2 E24.

 

[cliftonbros89]

I mainly work on farm equipment. Luckily there's never any e-torx. Very few torx. Most the metric fasteners are pretty common. Usually 7, 10, 13, 15, 18, 23, 24, 25, 30, and 32 mm. I have run into 19, 29, 34, and 36 before but not often at all. Luckily that's just on the newer stuff. Most anything pre-1990's is usually all SAE.