Common metric bolthead sizes ?

[Downwindtracker 2]

I was digging in my metric cabinet and checked what large metric wrenches I had. At work the 30mm and the 24mm were the only ones commonly used on the newer machinery. On some of the old machinery I used 21mm in place of 1/2" Whitworth. So besides 24mm and 30mm, what other sizes should I keep my eyes open for ?

 

[visionguru]

22mm is common for sensors

 

[wafrederick]

20mm on oil line fittings,a/c lines and GM fuel filters.18mm,15mm,13mm,10mm and 8mm on GM,Chrysler and Ford products.19mm,17mm,14mm,12mm and 10mm on most Asian makes.Sometimes run into 18mm and 16mm on some Nissans.

 

[Sidchrome]

Common large sizes I have seen used in heavy industry, especially Japanese equipment, metric nuts and bolts.
17 M10
19 M12
21 common M14
22 sometimes
24 M16 common
27 M18 common
30 M20 common
32 M22 common
36 M24 common
41 M27 common but big
46 M30 common but big

Sometime you come across cheaper nuts and bolts which are made from smaller stock, usually 1 mm less AF.
Automotive seems to be varied though.

 

[Downwindtracker 2]

Thanks, exactly the answer I was looking for. I'm missing the 27mm .

I once owned a Universal tractor, a FAIT made in Romania . After working on French and Italian cars as well as Mopars, I came across some 14mm . A WTF moment. I still remember that 40 years later.

 

[garfunkle24]

It depends whether it's SAE, DIN or JIS annoyingly.

DIN is 8mm, 10mm, 13mm, 17mm
JIS is 8mm, 10mm, 12mm, 14mm etc

 

[Downwindtracker 2]

When you say that annoyingly I had to laugh. On a job, my partner "Damm it, I have to pack All My Wrenches " As millwrights going on jobs we tried to carry as few as we could get away with, and that firm used heavy bolts and nuts. All odd sizes.

 

[Sidchrome]

When you say that annoyingly I had to laugh. On a job, my partner "Damm it, I have to pack All My Wrenches " As millwrights going on jobs we tried to carry as few as we could get away with, and that firm used heavy bolts and nuts. All odd sizes.

It’s pretty annoying when you know you have the right tool at home

 

[Dave455]

As garfunkle24 says, it depends on what standard is being used. American ANSI, German DIN, Japanese JIS and International ISO use different sizes. A quick search online will reveal the sizes used, though even then nothing is certain, as some of the standards change. DIN for example, is gradually coming in line with ISO.

Thankfully, in the larger sizes, there seems to be a lot of crossover.

22, 24, 27, 30, 32 and 36 seem to cover most requirements, but if you are going to find unusual sizes it’s generally machine tools where they lurk.

I’ve found real oddities over the years. I’ve found British machines destined for European customers that had bolts in the old British Standard Metric that pre dated ISO and used a totally different range of sizes (23mm I seem to recall was one). Also Swedish machines that had bolts with Whitworth threadform but metric bolt heads...!

If you need a Whitworth socket I’d probably pick one up. One advantage of Whitworth tools, if you buy used, is that supply generally exceeds demand, so really good quality tools can be obtained quite cheaply - except Snap On where they have rarity value for collectors!

 

[Downwindtracker 2]

Those Whitworth machines were '60s Japanese built on a '30s English design they had licensed . When our mill shut down they were bought by a Mexican firm. Thinking about it now, I wonder how they did setting them up again. The jobber made parts were a mishmash of 1/2"x12,1/2"x13 and 12mm. What ever the machinist felt like using.

 

[king nero]

What used to be common sizes, 17 and 19 mm (M10 and M12), have recently been replaced (especially in french cars) by 16 and 18 mm.

 

[Downwindtracker 2]

Oh joy, so far 10mm bolts we have 15mm,16mm, and 17mm heads now. Speaking about French cars, when I was young I had a Simca 1000 and then a Simca 1204., They used a lot of bolts with a 11mm head. The only place I've seen them.

 

[Samuel D]

What used to be common sizes, 17 and 19 mm (M10 and M12), have recently been replaced (especially in french cars) by 16 and 18 mm.

And German cars. These are the new ISO sizes, I believe.

 

[semi42]

For the smaller ones 6mm, 7mm(jubilee hose clips)And 8mm

 

[garfunkle24]

Metric would be so nice and simple if engineers could agree on standards.

 

[dutchgray]

What used to be common sizes, 17 and 19 mm (M10 and M12), have recently been replaced (especially in french cars) by 16 and 18 mm.

Even seen that in steel building construction, you do one and its all gone 18mm M12 then the next will be from another supplier and still be 19mm M12. Used to be simple now you need more tool sizes and cant easily tell by eye what you need.

 

[Sidchrome]

17 and 19 are better to work with imo.
Especially in industrial settings, pipe flanges etc , the flats last longer less likely to round off or be corrosion effected. I worked on a job site where replacement 16 and 18 nuts and bolts were bought in, nothing but a hassle, we went back to the larger sizes, which were harder to source in Aussie.
A good thing about metric is if you have a full set you cover just about everything especially in larger sizes and you can always bang the next size down onto a wasted nut and get it off.
Imperial is always nice to work with though, easy to tell sizes at a glance, good sizing and you don’t have to worry about different standards. Makes tool box easier to manage.

 

[dusterdude]

Buy a buttload of 10mm.you'll need em

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