Does anyone use these metric wrench sizes?

[48RON54]

Just ran into 25mm on the bottom of a fuel filter for a Cummins engine yesterday. I wondered to myself why they didn't go with 22mm or 26mm since both of those are in my socket set. 1" was close enough so I went that route with it.

 

[humpty]

I have a couple 7mm wrenches in my tool box from back in my wrenching days. I found uses on the older Japanese machine tools I worked on.

I am guessing they will never leave the tool box again...but you never know.

humpty

 

[Jack84]

I have a couple 7mm wrenches in my tool box from back in my wrenching days. I found uses on the older Japanese machine tools I worked on.

I am guessing they will never leave the tool box again...but you never know.

humpty

7 mm wrenches are used on m4 bolts. According to din 933.

 

[four.cycle]

OP: 6,20,23,25,26,29,31

I own a 6mm x 7mm open end, and i know I used the 7mm less than a year ago, but I think the last time I used the 6mm was in the early 1970's on my French 10-speed bicycle.

I own a 20mm x 22mm open end, but I do not believe I've ever used it.

My largest metric wrench is a 24mm, which I've never used.

I have sockets in all those sizes (up to 36mm) but those sizes you've listed have never been out of the box they came in from the factory.

 

[yrly]

OP: 6,20,23,25,26,29,31

I own a 6mm x 7mm open end, and i know I used the 7mm less than a year ago, but I think the last time I used the 6mm was in the early 1970's on my French 10-speed bicycle.

I own a 20mm x 22mm open end, but I do not believe I've ever used it.

My largest metric wrench is a 24mm, which I've never used.

I have sockets in all those sizes (up to 36mm) but those sizes you've listed have never been out of the box they came in from the factory.

The larger sizes would probably be (aside from industrial uses) farm equipment, maybe of imported brands, most of the domestic stuff was SAE and if they’ve switched to metric it’s pretty recent stuff.

Another one I remember being big is a Ford F150 pitman arm nut which is something like a 33mm. I think I had to use a 1” drive 1 5/16 because it’s torqued to 200ft lbs and add a decade of salt, good luck getting it off. I didn’t any such socket size in metric in 1” drive.

 

[Mecha]

I had to order a 26mm this week, it's for the arbor nut on the 8" bench grinder.

9mm are used on mid 80's Shimano front and rear derailleurs on the cable clamp nut.

 

[johnnyradiant]

My son uses a 26 somewhat regularly and then jumps up from there. Working on chairlifts.

 

[Ulrich1able]

I've only needed a 25mm wrench once, for the nut on an M16 bolt, which are usually 24mm.

I don't remember what brand of trailer it was, but it was an aluminum flatbed semi trailer, for the bolts that held on the axle subframes.

 

[HannibalLecter]

I've only needed a 25mm wrench once, for the nut on an M16 bolt, which are usually 24mm.

I don't remember what brand of trailer it was, but it was an aluminum flatbed semi trailer, for the bolts that held on the axle subframes.

Nice 3 year old thread bump mate I too have used a 25 mm wrench on a poorly made park tool bike cassette removal socket. I have used also the 6 mm I think and the 9 in a bleeder. Never a 20

 

[Samuel D]

I too have used a 25 mm wrench on a poorly made park tool bike cassette removal socket.

Those are nominally 1″. Park Tool makes a 3/8″-drive 1″ socket specifically for them.

Or is that what you meant by poorly made? Just checking you weren’t expecting it to be any metric size.

 

[Wrench97]

23mm on Mazda front strut bolts.
I used a 20mm the other day on Jeep tie rod nuts, a bit strange though I believe they were some cheap aftermarket tie rods the customer installed and then couldn't figure out how to make the wheels point straight and the have the steering wheel straight at the same time.
6mm on some stud ends.

 

[HannibalLecter]

Those are nominally 1″. Park Tool makes a 3/8″-drive 1″ socket specifically for them.

Or is that what you meant by poorly made? Just checking you weren’t expecting it to be any metric size.

Well, i thought that might be the case. I had a 25 metric and a 26. The 26 clearly didn't fit, too much slop. The 25 went in after some persuasion. Now, I don't have any imperial wrenches to verify if it was actually 25.4 or 1 inch, but 0.4mm seems like a lot deviation from 25.4 . But yes, it doesn't make sense to actually be a 25mm size. Couldn't they go with 26?

 

[chris142]

The engine oil cooler lines on Chevy trucks are a 20 mm. I used that size every day when I worked at a radiator shop.vthe rest I have never seen. A use for. Same for my 9mm wrenches. Never been touched

 

[Samuel D]

Speaking of non-standard sizes, yesterday I had the displeasure of trying to set the bearing preload in bicycle pedals with a 9 mm lock nut against a cone (race) with 11 mm flats. Who comes up with this stuff?

And the sizing was the least of my problems, because the dumb things had no access to the cone nut while tightening the lock nut. No tabbed washer on keyed axle to prevent the cone turning or anything like that.

Turns out I need a special tool like this one made by another company for its own similarly stupid pedals.

 

[HannibalLecter]

Speaking of non-standard sizes, yesterday I had the displeasure of trying to set the bearing preload in bicycle pedals with a 9 mm lock nut against a cone (race) with 11 mm flats. Who comes up with this stuff?

And the sizing was the least of my problems, because the dumb things had no access to the cone nut while tightening the lock nut. No tabbed washer on keyed axle to prevent the cone turning or anything like that.

Turns out I need a special tool like this one made by another company for its own similarly stupid pedals.

Well for machined flats on a predetermined axle that has to go in a recess , with a hole running through, i kinda expect it. You have to go with anything that fits. And bike industry especially aren't very bright on these kinds of things. That's why knipex pliers are nice, takes out the guesswork and accommodates stupid sizes

 

[Samuel D]

Well, i thought that might be the case. I had a 25 metric and a 26. The 26 clearly didn't fit, too much slop. The 25 went in after some persuasion. Now, I don't have any imperial wrenches to verify if it was actually 25.4 or 1 inch, but 0.4mm seems like a lot deviation from 25.4 . But yes, it doesn't make sense to actually be a 25mm size. Couldn't they go with 26?

Even 26 mm would bother me. What’s wrong with bog standard 24 or 27 mm?

But the bicycle world, like motorcycles, has more than its fair share of weirdness. As Frank Berto wrote:

The lack of standardization in the bicycle industry is a horror story. It just proves that we’re still basically a cottage industry.

And it’s only got worse since he wrote that in 1988.

 

[mike710967]

Not to hijack your thread, but 16mm is the one size I’ve NEVER come across. 90% of my work has been done on Jap vehicles, 10% American. 0% Europe.

 

[Beerhippie]

I've used them all up to 30mm. Anything bigger than that goes to someone who has the tools.

6mmi s very common for electrical connection boxes on Euro motors--but generally a nutdriver or spinner handle and 1/4 socket are the right tool.

First time I ever encountered 16mm was the valve covers on Honda 4-cylinder transverse motorcycle engines--CB series--in the '70s. 5.8" is a close enough cognate.

Alfa-Laval Brew 80 centrifuge uses just about every size of metric wrench you don't have. Lovely device.

 

[Wamsutta]

Not to hijack your thread, but 16mm is the one size I’ve NEVER come across. 90% of my work has been done on Jap vehicles, 10% American. 0% Europe.

The parking brake cable tension adjuster on the 2000-2005 Buick uses some nuts that are 16mm.

 

[mreisner]

John Deere uses a lot of odd size metric bolts

 

[Ulrich1able]

John Deere uses a lot of odd size metric bolts

Was taking a PTO off an Allison 3500 and the PTO bolts were a 3/8-16 thread with a 10mm 12point head.

Is that considered a metric or standard bolt

 

[oldschoolcraft]

Better to have and not need is the GJ motto...

NO SKIPS!

 

[f121]

Not to hijack your thread, but 16mm is the one size I’ve NEVER come across. 90% of my work has been done on Jap vehicles, 10% American. 0% Europe.

Used a 16mm at the weekend, sump plug on a 2005 4.6 Mustang.

Just looking at my combination wrench set to see the sizes between 6 and 32 mm I don't have if I should have. 6,20,23,25,26,29,31. Anybody ever use those?

6, 20, 25 occasionally, 23 a lot. Never seen 26/29/31. Are they even a thing?

 

[oldschoolcraft]

Not to hijack your thread, but 16mm is the one size I’ve NEVER come across. 90% of my work has been done on Jap vehicles, 10% American. 0% Europe.

My Japanese vehicle uses a 5/8" spark plug socket. I was looking at Koken today for spark plug sockets and they dont make 5/8" which is odd because Koken is a Japanese tool company and my car is Japanese.

And then I realized, why is my Japanese car using SAE sized spark plugs?

As it turns out, 5/8" spark plugs are 16mm. 5/8" is technically 15.87mm but Koken lists their spark plug sockets as 14mm, 16mm, 18mm and 20.8mm (which is = 13/16").

And 9/16" spark plugs use the 14mm Koken spark plug socket.

 

[Wrench97]

Was taking a PTO off an Allison 3500 and the PTO bolts were a 3/8-16 thread with a 10mm 12point head.

Is that considered a metric or standard bolt

Hybrid nut.

 

[honcho]

84 Volvo 4 Cylinder B23 oil drain plug, 25mm

 

[dscheidt]

Was taking a PTO off an Allison 3500 and the PTO bolts were a 3/8-16 thread with a 10mm 12point head.

Is that considered a metric or standard bolt

somebody wrote a spec that limited what tools were allowed to be used for routine operations. there was a whole lot of this on detroit stuff in the 80s and 90s, because there were federal procurement standards that required some common operations to be done with a specified toolkit. It is much cheaper and faster to make weird bolts than to redesign a transmission casting.

 

[j-becker]

A few years ago I was also interested in what the actual, commonly, used metric wrenches were. So, found this table of metric fastener sizes to use as a reference and added wrench info. I won't guarantee it is complete and it includes only standard metric fasteners ... doesn't include tube fittings, special applications, etc.

I'd be interested in any information that others may be able to provide to help improve the scope of the summary!

Came across this old post -- not sure if this is still of interest: DIN actually recommends usage of certain threads/bolts over others ("Gewinde Reihe 1, 2,3"). So you will find in general more bolts with nominal diameter 6/8/10/12/16/20 than 14/18 (Reihe 2) or even 7 (your only entry from Reihe 3). But the larger the manufacturer the less the cost incentive to stick to the rules....