# Thread: "D10"tolerance on a bored hole

1. ## "D10"tolerance on a bored hole

Anyone have the conversion of this tolerance call out "D10" it is being used on a bored hole 30.025 diameter????????

2. check this out....

regards

3. ## Thanks for the direction

I also found another web site after posting "Maryland Metrics"

4. 30.025 mm hole and a D10 (+80/+180) tolerance????????
Typical for somebody not knowing his way around metric. 30 D10 would be just fine.
One can see how much being illiterate in metric is costing us. I hope they do not sent this to any other country - not a good presentation of American engineering.
Juergenwt

• Actually the information is in thousands of mm so the tolerance would be +.080/+.180mm

Best regards

Bruno

• Bruno -look at it again. Juergenwt

• juergenwt,
nominal diametre sizes are in mm, tolerances are in .001mm.
I took you +80/+180 for granted and I shouldn't have.

A 30.025 mm hole is in fact a 30mm nominal hole with a tolerance of +65/+149 the fundamental lower deviation is +65 for a D tolerance the IT grade is an IT10 of +84:
MAX hole size = min hole size + IT => 30.065mm + .084mm
MAX hole size is : 30.149mm

you can refer to machinery's handbook 27th ed page 684 "British Standard Limits and Fits" and page 687 "British Standard Fundamental Deviations for Holes"

If you transfer back the min-MAX hole sizes to the 30.025mm hole the tolerance is +40/+124 microns (.001mm) so the min-Max hole are as above.

This is how I've learned it, If I tripped over something, please let me know where I did.

Best regards

Bruno

• Hello Bruno-direct from the ISO tolerance table: D10
Over 18mm and up to 30mm - +65µ / +149µ
Over 30mm and up to 50mm - +80µ / +180µ

30 D10 is over 30mm.
The +80/+180 tol. applies.

Sorry Bruno - I do not have a British Standard available to me in the US.
Pls. let me know if you agree.
What I really think is that somebody not familiar with metrics wanted to cover his rear and put these dim's (30.025 D10) on a print. It happens quite often in the US and I can understand why. People can not think in metric and it will take a generation to overcome this problem - providing we can get past our politicians and change our school system to teach nothing but metric. But that would be asking a lot.

Thanks Juergenwt

• Juegenwt,
Tolerances are applied to the NOMINAL diameter, a bored 30.025mm IS a 30mm NOMINAL hole size tolerances are +65/+149. That's theory.

Practically D10 is only half of the puzzle, the hole will mate to a shaft according to a specific shaft, if the shaft is a purchased item, then a reverse calculation must be made according to the fit tolerance and then the hole tolerance must changed according to the fit tolerances. Confused?. It's part the "YOYO" calculations required for getting the correct fit. That not only applies to ISO standards (metric) but also to ANSI standards (imperial).

The only thing that is really complicated in the ISO standards of measurement it's fit tolerances in both shaft and bore tolerances, there are too many exceptions you would believe they were written by politicians.

Best regards

Bruno

• Originally Posted by juergenwt
Hello Bruno-direct from the ISO tolerance table: D10
Over 18mm and up to 30mm - +65µ / +149µ
Over 30mm and up to 50mm - +80µ / +180µ

30 D10 is over 30mm.
The +80/+180 tol. applies.

Sorry Bruno - I do not have a British Standard available to me in the US.
Pls. let me know if you agree.
What I really think is that somebody not familiar with metrics wanted to cover his rear and put these dim's (30.025 D10) on a print. It happens quite often in the US and I can understand why. People can not think in metric and it will take a generation to overcome this problem - providing we can get past our politicians and change our school system to teach nothing but metric. But that would be asking a lot.

Thanks Juergenwt
NO... 30 D10 is NOT over 30mm. It is equal to 30mm. So it would seem that +65/+149 applies. But 30.025 IS over 30mm. In that case, +80/+180 would apply.

That implies one cannot simply write 30 D10 instead of 30.025 D10 because they mean different things.

Ken

• I guess the real question is whether 30 D10 is over 30.000 or not. If the nom. dim. is 30.000 than it looks like +65/+149 is the correct answer. I would like to thank everybody for taking part. Thank you - juergenwt