Threaded hole specification

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mattheus
Posts: 1542
Joined: 29 Dec 2008, 12:57pm
Location: Western Europe

Threaded hole specification

Postby mattheus » 5 Feb 2020, 10:51am

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
Posts: 951
Joined: 10 Jan 2014, 8:39am

Re: Threaded hole specification

Postby alexnharvey » 5 Feb 2020, 10:58am

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
Posts: 37472
Joined: 4 Jan 2012, 6:25pm

Re: Threaded hole specification

Postby Brucey » 5 Feb 2020, 2:55pm

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
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

mattheus
Posts: 1542
Joined: 29 Dec 2008, 12:57pm
Location: Western Europe

Re: Threaded hole specification

Postby mattheus » 5 Feb 2020, 8:08pm

thanks chaps!

hayers
Posts: 130
Joined: 27 Apr 2016, 1:50pm

Re: Threaded hole specification

Postby hayers » 7 Feb 2020, 5:00pm

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
Posts: 1542
Joined: 29 Dec 2008, 12:57pm
Location: Western Europe

Re: Threaded hole specification

Postby mattheus » 9 Feb 2020, 9:01am

hayers wrote: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 :)