[thumper]

Still building my tool set...(you can never have enough tools)

Why do some metric sets exclude some sizes?

I've got the standard 6mm - 19mm set, added the 20, 21, 22mm 24mm and 27mm.

but I'm missing the 23mm 25mm and 26mm.

Why do most "SETS" exclude these three sizes? Are they odd and not used alot?

Do I need to add them to my set just in case?

I'd hate to spend money just to have them to look at and never use them.

Opinions or comments.

thanks

 

[tok-tokkie]

Metric bolts come in a graded set of standard sizes based on the diameter of the bolt: 2, 3, 4, 5, 6, 8, 10, 12, 16, 20, 24. They have standardised nut sizes so there are matching gaps in the spanner series. Recently they have changed the size of the 10mm nut from 17mm to 16mm. Most old sets of spanners do not have a 16mm spanner. I am not aware of any other sizes being changed like that but they may have.