Screw dimensions

[4yuckfous]

what exactly means the digits behind a screw dimension
for example 7/16 -20
or 7/16 - 24

[wagesofsin]

for example:  7/16-20  is 7/16 bolt , 20 threads per inch.

[4yuckfous]

Thx
I love our metric screws much easier

[HP2]

It really is pretty simple. Threads are bascially fine or course. The bigger the number, the finer the threads.

Ya know, I've run into various pitch metric fasterners, so they have variations as well. For example, you can get M8 in either a 1.25 or 1.5 pitch

[quagmire]

 

Yeah, some of the metric sizes can have as many as 3 different thread pitches for a given bolt size.  I believe M10 or M12 are that way.  Found that out when I had to retap a hole, guess which of the three taps I ddin't own or could find easy?   

[4yuckfous]

 

[the_engineers]

Yeah, some of the metric sizes can have as many as 3 different thread pitches for a given bolt size.  I believe M10 or M12 are that way.  Found that out when I had to retap a hole, guess which of the three taps I ddin't own or could find easy?  

US or SAE threads are the same way...most are available in two sizes, UNC (Coarse) and UNF (Fine) and some are available in UNEF.

Here's a link that may help with the confusion.
http://en.wikipedia.org/wiki/Unified_Thread_Standard