I do understand that GD&T defines surface outline better than Coordinate. Yet something like this is in Wikipedia "According to the ASME Y14.5-2009[2] standard, the purpose of geometric dimensioning and tolerancing (GD&T) is to describe the engineering intent of parts and assemblies. The datum...
Seem this issue as caused quite a bit of confusion. I found in another topic in the forum while looking for more information.
"I talked with Paul Drake (author of Dim & Tol Handbook (McGraw Hill)).
His suggestion is to use the same general tolerancing method as we always have and ignore the...
Hmmmm maybe I'm reading wrong or in the wrong forum. "If the print is designed per the ASME standard then the parts are out of spec. If you design to a different standard which incorporates the rounding rules you specified, then you would be correct, as long as it's clearly spelled out what...
http://faculty.uml.edu/bkim/22.201/tolerance1.pdf shows difference between metric and inch tolerance dimensions. Some place I when searching was only listed as chapter 5 and all prefixes on chapters started with 5 but the above show the same and implies decimal significance.
10% of anything is...
Hope it fits is not an option. Made to print parts fit or print is wrong! I have looked online and can't find much of the ASME Y14.5 but what I do find does not support unlimited decimal places. In chapter 5 it states for example 5.250 +/-.010 is correct but 5.25 +/-.010 or 5.250 +/- .01 is Not...
Consider the following hole diameter tolerances that might appear on a drawing:
.505 +/- .005
.5050 +/- .0050
.50500 +/- .00500
Do you agree that these all mean exactly the same thing? If not, please explain why.
+/- .005 implies no 4th place so .0054 estimated 4th place is .005...
My point is simple. Why is there significant decimal rules if they are not used. I'm not talking high production but 100% inspected parts made to a print that has a general tolerance listed that's associated with the number of decimal places unless otherwise specified. You list the 1/10 rule but...
The problem with a digital caliper is they are flimsy, not ridged like a much higher price Vernier caliper! I have the latest version of Starrett Digital Caliper and will not measure to .001 with it! Yet the display on most digital calipers is 4 places! Yes I know about the ratchet stop, 3...
I am very familiar with rounding of numbers. If anything those to the right of a decimal place and to the significant decimal place I target. Reading that site was rather simplistic nor does it explain the rounding of 5. 1,2,3 and 4 are rounded down to 0. 6,7,8 and 9 rounded up to 1 (10) But 5...
Using a Dial Caliper to measure 3 place decimal is not good and rounding 4th place when there is very little space between the 3 place graduations. If I had a machinist using a dial caliper for 3 place decimals I'd fire him! Then comes the next piece of junk the digital caliper. Though more...
No I don't think less accuracy is good! Rounding as in significant numbers is not being less accurate, Possibly more accurate. Quite a few examples when Googling Significant figures state the a measure number is accurate to the number preceding the last digit. If using a micrometer (the typical...
So what your saying is if a hole for a bolt is dimensioned in Inches, not mm .505" +/-.005" to fit a bolt that is deminesioned .500" +.000"/-.005" the part is to be rejected if the hole measures .50501". To be honest it would be stupid to measure that hole that accurately! Plus if it were and...
Yes I'm talking about measured dimension. Not that a number on a drawing can be interpreted differently. Simple example Print dimension of a shaft is 6.000" +/-.005 When completed shaft is measured by customer it is 6.0051", is this acceptable? Or is it rejected? Pushing that farther it's...
Yes I understand that, the meter is "fractioned" into dm,cm,mm,um and nm but inch isn't. Decimals are a means of division by 10. Nor am I speaking of Automotive high production large facility operations. The small machine shop keeps the small companies operational. A shaft for a conveyor belt...
I'm the same, I calculate the limits, I do not pick a number out of a hat. But typical drawing and a dimensional tolerance chart like .XXX = +/-.005 When calculated tolerance is lets assume +/-.006 I use the listed number. The added cost limiting the tolerance .001 will not increase the cost...
I have seen that designation 12.2 means 12.000..00 and so on in some other thread but later in the thread it mentioned it was for metric which I can understand because metric mm is 1/25.4 of an inch. Also above 10% was mentioned so that contradicts 000....000. I'm also thinking that 10% would be...
Don't misunderstand my questing, I'm acting as devils advocate. If I were to tell a machine shop their part was rejected and provide the example give with the 1/10 of tolerance range I envision their reply being where is that proven. Significant figures are well defined in many Googled sites...
Then would that be a conflict with significant numbering? Significant numbering is used quite a bit in other Engineering. If an error is made and that is what tolerance is because nothing can be made perfect! If in fact like my previous example it did not make a difference requiring measurement...
That's assuming the drawing is for quite a few parts. If on 10 items I wanted .003" clearance between a pin and hole and use +/- .005 as tolerance then at maximum material condition I would have to dimension a size difference between the pin and hole so at MMC there is .003" if the parts came...
New here, Long time Engineer currently retired. But often asked to provide answers. The typical topic often asked is the definition of significant numbers in interpreting dimensions on drawings.
If an item dimension is 3 decimal paces on the drawing with a unilateral 3 decimal tolerance I...
