Fastener Sizes

[The Critic]

I primarily own and service Asian Import vehicles, so JIS usually applies to me. It explains why 10/12/14/17/19/22 (occasionally) are what I use.

For Domestic vehicles, I am aware that 15MM is used quite a bit…presumably for M10? If so, it seems like they are not adhering to ANSI or ISO.

 

[atikovi]

A lot depends on the application. An M14 head bolt could have a 18mm head if there isn't much room around it.

 

[Hall]

Always roll my eyes when someone calls a fastener a "10mm screw" because it has a 10mm hex head

Trivia question: What's the difference between a bolt and a fastener ?

 

[bdcardinal]

Always roll my eyes when someone calls a fastener a "10mm screw" because it has a 10mm hex head

Trivia question: What's the difference between a bolt and a fastener ?

A bolt is a bolt, a fastener is any object that fastens. Its been a while since I have read Carrol Smith's books, but I think that was a good paraphrase.

Also FWIW ARP has a lot of hardware that has smaller size heads than the OE fastener to help with access.

 

[D60]

Ford loves 15mm bolt head with 18mm nut. I almost think some of it is M12 with a flange head on the bolt?

Many domestic serpentine tensioners/pulley bolts are 15mm.

 

[flanso]

Porsche 356s used 8mm diameter bolts with 14mm head size. In good condition, those obsolete, original bolts and their 14mm wrench size nuts are highly coveted by 356 purists.

 

[tom slick]

Always roll my eyes when someone calls a fastener a "10mm screw" because it has a 10mm hex head

Trivia question: What's the difference between a bolt and a fastener ?

Do you mean a bolt and a screw? They are all screws until you use a nut to fasten, then it is a bolt connection.

 

[2EHA]

“remove the 17mm wheel screws”

see how goofy that sounds?

 

[Hall]

Do you mean a bolt and a screw? They are all screws until you use a nut to fasten, then it is a bolt connection.

I should clarify that I was taught this (below) at a company I worked at as a mechanical designer and the definition could have simply been a "company standard" or it could have been from ANSI. Anyway....

• A bolt threads into a nut
• A fastener threads into a threaded hole