20 or 21mm?

[HighMileage]

So I bought a rusty set of Mac deep metric impact sockets. They are in an original upright tray thingy. I cleaned them all up but I’m missing one. There’s a 19mm then an empty space then 22mm.

Should I put a 20 or 21 in the missing spot?

Thinking of just going to Lowes and getting a Craftsman socket.

Thx!

 

[Team Canada]

From a Canadian perspective, where metric has been in use since 1975, buy a 21mm. It's a 13/16 in a pinch.

 

[TurboTGuy]

If a 21mm = a 13/16, then why not get the 22mm?

That is, of course, assuming you have a 13/16 socket already.

 

[Team Canada]

The way I read his post, he already has a 22mm.

 

[HighMileage]

If a 21mm = a 13/16, then why not get the 22mm?

That is, of course, assuming you have a 13/16 socket already.

I’ve got every 13/16 imaginable from a crows foot to each socket.

I have a 19 and 22 in that set but there is one slot between the two. It’s not labeled.

 

[HighMileage]

The way I read his post, he already has a 22mm.

Looks like I had better get a 20mm. But I can’t remember ever needing a 20 for anything.

 

[Team Canada]

Assuming these tools are primarily for automotive use, consider a 21. Especially if you ever cross paths with any European or Japanese vehicles.

 

[TexasT]

The only 20mm thing I can think of is the fuel filter and that won't use a socket. That said I don't know of anything I've used a 21mm for.

 

[HighMileage]

Ok,I can’t find a 20. I bought a 21mm.

This rack of Mac sockets is intentionally missing 20mm and 23mm for whatever reason. It goes from 10mm to 24mm.

Thanks everyone for your help.