Metric square fasteners?

[shanny19]

Where are square metric fasteners used? I just came across a GP socket set for square metric in larger sizes.
I've gotten occasional use out of my 8 pt. SAE sockets, esp. on older furniture and my antique tractors, but where might I find a metric square anything???

 

[Fretters]

No idea if they're still the norm these days, but coach bolts would be one possibility. Square nuts always seemed to be the nut of choice with those, including last time I saw some new, (which was a good few years ago now, granted).

 

[Guns R Tools]

Maybe drain plug application.

 

[Dave455]

I don't see a lot of these in metric, though as Frettters says, I've found them on coach screws. Even these tend to have hex heads these days.

Metric sockets get used for a lot of stuff other than nuts and bolts though. I do a fair amount of machine setting, and I'm always using square sockets for things like toolpost studs, tool clamps, machine vices and leadscrews. Anything with a square shaft really.

Most if the stuff I work on is imperial sized, but if you work on Metric machines, a set of these sockets would be pretty handy!

 

[SASORacing]

Stuff like this happily gets my old MAC crescent wrench some use. However I have never came accross a large square that I remember.

 

[mnbaty]

Komatsu uses them for test port plugs.

 

[mrborohachi]

Nissan cars ****** fill or drain, in the 90's i know for sure have a square plug