Threaded hole specification

[mattheus]

thread gurus (or better still, machinists), tell me everything you can from the following spec (on a drawing):

7-TAP M3x0.5-6H THRO'


I'm listening ...

[alexnharvey]

7 don't know, possibly the item reference number on the drawing.
TAP a tapped threaded hole
M3 diameter, 3mm.
0.5 mm, thread pitch.
6H tolerance of the work, 6H is average quality of fit between the threaded parts.
Thro, abbreviation of through, as in the hole penetrates the part rather than being 'blind'

[Brucey]

sounds reasonable to me.

FWIW proper drawings are done to standards. It should say on the dwg what standard it is done to, and then the meaning should be unequivocal, provided you use the standard.

cheers

[mattheus]

thanks chaps!

[hayers]

The "7" might also be the number of holes - would more commonly be shown as "7 x tap m3..." or "ta m3... 7 places" but I've seen lots of variations. Used to avoid cluttering the drawing labelling every hole.

Of course if there's not 7 holes jn the OP's part this isn't the case here...

[mattheus]

The "7" might also be the number of holes - would more commonly be shown as "7 x tap m3..." or "ta m3... 7 places" but I've seen lots of variations. Used to avoid cluttering the drawing labelling every hole.

Of course if there's not 7 holes jn the OP's part this isn't the case here...

That is indeed correct for the OP's part - it has 7 holes