ISO dimensioning
ISO dimensioning
(OP)
What is the ISO standard for calling out holes? I have a new boss, and he likes symbols for everything. My old boss didn't care too much. I used to dimension holes this way:
4x M3X0.5, 5 DP
PREHOLE 6.5 DP, C0.3
My new boss says ISO standard uses symbols for depth, and countersink and diameter for the chamfer.
Is he correct
4x M3X0.5, 5 DP
PREHOLE 6.5 DP, C0.3
My new boss says ISO standard uses symbols for depth, and countersink and diameter for the chamfer.
Is he correct





RE: ISO dimensioning
Check out forum1103: Drafting Standards, GD&T & Tolerance Analysis.
From what I have seen of the ISO specification, I strongly prefer ASME Y14.5M-1994. The symbols are very similar.
JHG
RE: ISO dimensioning
RE: ISO dimensioning
It says the Counterbore, Countersink and Depth symbols are 'proposed' for ISO. So in 1994 I guess they weren't yet in the ISO, not sure about now.
I will say this, according to ISO you don't normally show the pitch for standard 'course' pitch. So M3x0.5 is normally just M3.
Also I'm not entirely sure what you're saying in the second part of the callout. Is this meant to be the lead in? Countersinks are usually given by diameter and angle, even in Iso as I recall.
KENAT, probably the least qualified checker you'll ever meet...
RE: ISO dimensioning
Examples:
M6 x 20/φ4,8 x 24
Which means a hole with ISO metric thread, 6 mm major diameter, 20 mm thread depth, initial hole diameter was 4.8 mm, and total hole depth is 24 mm.
As stated by KENAT, pitch is not always specified (although it doesn't hurt, and is not discouraged).
There are symbols for countersinks, whether holes are drilled in a workshop and fitted on site, or drilled and fitted on site, etc.
Regards,
Cory
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RE: ISO dimensioning
I don't remember doing the second half like that in UK but maybe I've been americanized now!
KENAT, probably the least qualified checker you'll ever meet...
RE: ISO dimensioning
RE: ISO dimensioning
Yes, the second part of the above call out is for the drilled prehole depth. This must be a Japanese thing too. The US and Japan can't agree on anything. Japan uses JIP and the US uses ISO....can't we all just get along?
RE: ISO dimensioning
RE: ISO dimensioning
No everyone can't just get along, cause ISO sucks in some areas
Per American, and in fact as I recal, UK convention you don't put the tap drill info on the drawing as that's specifying a process etc.
I guess the japanese like it.
Hmm, which is the more dominant engineering force...
KENAT, probably the least qualified checker you'll ever meet...
RE: ISO dimensioning
I know the US uses ASME, I was referring to the Japanese owned company I work for in the US.
As for the dominate engineering force....I say it's the one who holds all the cards and signs my paycheck!
RE: ISO dimensioning
Matt Lorono
CAD Engineer/ECN Analyst
Silicon Valley, CA
Lorono's SolidWorks Resources
Co-moderator of Solidworks Yahoo! Group
and Mechnical.Engineering Yahoo! Group
RE: ISO dimensioning
In an application where I was forced to really care about the thread strength I might specify a percent of thread, which would define the tap drill within limits.
Some thread inserts (Keensert) are installed in a hole tapped to a standard screw thread, but a larger than std tap drill absolutely must be used.
RE: ISO dimensioning
So generally you want to define what thread form you need to end up with.
KENAT, probably the least qualified checker you'll ever meet...