1/2 inch vs 13 mm.

[bmaverick]

Its a stretch to use those two interchangeably. On something that isnt super tight or rusted....sometimes I grab a 13mm if I see that wrench/socket before I see the half.

Half is a TIGHT fit on some 13mm stuff and a good choice if your worried about rounding. But those two really "shouldnt" be interchanged. But several others are MUCH closer....commonly:

8mm - 5/16..........0.315" - 0.3125"..........+/- 1%
11mm - 7/16........0.433" - 0.4375"...........+/- 1%
14mm - 9/16 ........0.551 - 0.5625"..........+/-2% (this one is almost as bad as 1/2 vs 13 mm)
16mm - 5/8" .........0.630 - 0.625.......+/- 0.8%
19mm - 3/4" ...........0.748" - 0.750....+/- 0.3% (dead ringer given mfg tolerances. Im convinced they are the SAME mold just labeled differently)
22mm - 7/8............0.866 - 0.875.... +/- 1%
24mm - 15/16......0.945 - 0.9375....+/- 1%

The metric "bastards" with nothing close are 10,12,15,18.....and those are VERY common if you wrench on cars and small equip

what is the 4mm then ?

 

[MoKelly]

I just put together some chairs where the instructions said to use either a 1/2 or 13mm wrench.

Since I’m guessing the chairs were made in China I used 13mm.

It all went fine.

 

[Oaktree]

When I got my first socket set for Christmas many years decades ago they didn't include a 13mm. Or maybe it was 1/2 inch.

That's weird, one of the more common bolt sizes. Some socket sets seem to leave out a 16 though.

The metric "bastards" with nothing close are 10,12,15,18.....and those are VERY common if you wrench on cars and small equip

Can't say I need a 12 much, but the others...yeah.

 

[Joel/ak]

I wouldn't know. My 1/2" and/or 13 mm must identify as a 10mm. I can never find them

 

[34Willys]

With a 12mm and 14mm I can almost totally disassemble my '92 Toyota pick up truck.
Patrick

 

[grsthegreat]

This drives me nuts when i service valves on Generac air cooled engines. About half the time my 1/2” crowsfoot wrench wont work and i have to use 13mm. Maybe 50% of the time. The engine is made in USA…..
should not need metric anything. But they switch between both standards throughout unit.

 

[Oaktree]

This drives me nuts when i service valves on Generac air cooled engines. About half the time my 1/2” crowsfoot wrench wont work and i have to use 13mm. Maybe 50% of the time. The engine is made in USA…..
should not need metric anything. But they switch between both standards throughout unit.

And my HF Predator engine has American threads on the mounting holes near the output shaft. And you know what country that was made in...

 

[EdwardL]

I only use 6-point sockets. Problem solved.

 

[Hay Dude]

Welcome to the true joys of British engineering. And, yes, I would purchase the sets. Too much heartache and skinned knuckles trying to find something "close".

All the best,

Peter

Does that include British Pipe Thread? Man I can stand it when they use that.

 

[LD1]

what is the 4mm then ?

4 / 25.4 = 0.1575"

A hair bigger than 5/32" but now your talking hex-keys most likely if you are working with stuff that small. And with hex heys....about the only ones I will interchange are 8 and 5/16. Cause aint much worse than a rounded out hex-key or bolt