Thread: Metric or Imperial?

Pretty sure its 9/16

Originally Posted by uninformed

Pretty sure its 9/16

Yep, the old standard for imperial bolts and nuts was 1.5 times the shank diameter.
1.5x3/8 is 9/16.

But 14mm usually fit too.

yep and I gestimate metric bolt dia + 5mm....that was untill they started putting 17mm hex on M10.

Now im far from an engineer, but I dont see the point in a head that big on a 10mm bolt??

I like to add my 2c , this has been mentioned before , put the tools you want too carry bag , better than a steel tool box , they don't rattle or slide around the same . There are a good selection of strong tool bags , with lots of side pockets for small bits and pieces , they don't cost a lot !!..cheers Jim

Originally Posted by uninformed

yep and I gestimate metric bolt dia + 5mm....that was untill they started putting 17mm hex on M10.

Now im far from an engineer, but I dont see the point in a head that big on a 10mm bolt??

I think for metric they started with rounding imperial sizes off to the nearest mm.
Then the Japanese made lightweight metric bolts, 14mm head on m10 etc.
Now I see a lot of 15 and 16mm m10 and 18mm m12. Sizes that didn't used to exist.

Originally Posted by Dougal

I think for metric they started with rounding imperial sizes off to the nearest mm.
Then the Japanese made lightweight metric bolts, 14mm head on m10 etc.
Now I see a lot of 15 and 16mm m10 and 18mm m12. Sizes that didn't used to exist.

in my short wrenching time, 13mm was standard on M8, 15mm on M10. This of coarse does not include those flange head bolts that have smaller hex, like the M8 on the R380 that have a 10mm hex.

Go to carpentry and the industry standard for my last 20 years is 18mm on a M12. Though you do get the odd brand that loves to put a 19mm hex on a M12, which buggers you up especially if you custom make sockets.

Originally Posted by uninformed

Pretty sure its 9/16

Originally Posted by Dougal

Yep, the old standard for imperial bolts and nuts was 1.5 times the shank diameter.
1.5x3/8 is 9/16.

But 14mm usually fit too.

Yep, bolt head size is that, but the nut hex is reduced when you use a K nut !

Trying to find M10x1.0 (not 1.5) pitch bolts in 8.8 and 12.9 ATM....

Originally Posted by uninformed

in my short wrenching time, 13mm was standard on M8, 15mm on M10. This of coarse does not include those flange head bolts that have smaller hex, like the M8 on the R380 that have a 10mm hex.

Go to carpentry and the industry standard for my last 20 years is 18mm on a M12. Though you do get the odd brand that loves to put a 19mm hex on a M12, which buggers you up especially if you custom make sockets.

I'm still buying stainless m10 with 17mm heads and stainless M12 with 19. But all the galv and zinc bolts are usually 16 and 18. The socket and spanner sets I bought 10 years ago don't have 16 or 18mm.

So the last spanner set I bought has all of them. 1mm increments from 6-20mm.