NA Miniature metric fastener question

[MadMike08]

For some reason I cannot find actual fastener dimensions and tolerances for miniature metric fasteners. I have a fit probelmn with miniature components, where a few thousandths makes a difference.
How do I find the tolerance for the threaded length of a mini metric fastener? It's an M2 x 6mm SHC screw. I would like to know what the range is for the thread length in a tight application.

 

[KENAT]

For fasteners, the 'nominal' length is almost always the maximum length (I've never seen different).

What spec are your fasteners purchased to?

If not purchased to a spec then you'll never get a meaningfull answer.

I'm not aware of differences in length tolerance between North American and rest of the world screws but there are differences in some head dimensions.

KENAT, probably the least qualified checker you'll ever meet...

 

[MintJulep]

From ASTM B18.3.1M:

Nominal Screw Size M1.6 through M10
Nominal length up 16 mm: Tolerance on length = +/- 0.3mm

 

[MadMike08]

The fasteners are purchased to the NA spec. (NA0069-020006.

I had assumed that the nominal length was the maximum, but I wanted to confirm that.

As far as the minimum length is concerned, I've not seen it specified.

I have a situation where no tolerance analysis was evidently performed, since I have fasteners bottoming out in precision slides. The problem is that in such a case, if the fit is line to line, and it seems adequate in assembly, failures in vibration and thermal can occur. There can be minimal clamping force.

3mm of thread going into a 2.5mm threaded hole.

Thank you for the info....

 

[KENAT]

Thanks Mint, interesting I've never seen +-, always just - on screw thread lengths. Guess I'll have to look again.

KENAT, probably the least qualified checker you'll ever meet...