Grip length for NAS1352C4-12

[Steve6511]

Does anyone have the grip length for NAS1352C4-12 Cap Screw?

NAS spec refers to ANSI/ASME B18.3, and we don't have this spec.

 

[rikman]

Steve,

If I've read the part number correctly, this is a fully threaded fastener so it won't have a recognised grip length as such. I think that where the spec refers to grip length, they mean for those screw lengths where the minimum thread length leaves part of the shank unthreaded.

yours,
Rikman

 

[Steve6511]

The note on NAS1352 states "Screws which have a grip length less than the minimum basic thread length, shall be threaded as close to the head as practicable. For screws that have a length greater than the minimum basic thread length, the body and grip length shall be in accordance with ASME/ANSI 18.3."

 

[rikman]

Steve,

My copy of the spec may be out of date (1996): the note on mine states:

(C ) SCREWS WHICH HAVE A LENGTH LESS THAN THE MINIMUM BASIC THREAD LENGTH, SHALL BE THREADED AS CLOSE TO HEAD AS PRACTICABLE. FOR SCREWS WHICH HAVE A LENGTH GREATER THAN THE MINIMUM BASIC THREAD LENGTH. THE BODY AND GRIP LENGTHS WILL BE IN ACCORDANCE WITH ASME/ANSI 618.3.

Regards,
Rikman

 

[yates]

Steve6511,
Rikman is right, grip length for your NAS1352C4-12 screw is zero, since total length is .750 inches and minimum basic thread length for size 4 (1/4 inch) screw is 1.000 inch. ASME/ANSI B18.3 only helps you with tolerance on grip length if total length is greater than min. basic thread length. By the way, min basic thread length, as defined by B18.3 is from end of screw to last full thread. So total length minus min. basic thread length leaves you with a wierdo call 'Grip gaging length' - not exactly the same as grip length, the difference between the two being the imperfect thread length.Last issue of NAS1352 is 9 dated 31 May 1996

 

[Steve6511]

Thanks guys, for the help.