A quick question on total runout
A quick question on total runout
(OP)
My question is this:
If I specify a total runout of 0.05mm on an OD of 6.05 +/-0.05mm, does that mean when it gets inspected by QA the maximum allowable diameter is 6.15mm or 6.1?
If I specify a total runout of 0.05mm on an OD of 6.05 +/-0.05mm, does that mean when it gets inspected by QA the maximum allowable diameter is 6.15mm or 6.1?





RE: A quick question on total runout
RE: A quick question on total runout
Powerhound, GDTP T-0419
Production Supervisor
Inventor 2008
Mastercam X2
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II
RE: A quick question on total runout
Dave D.
www.qmsi.ca
RE: A quick question on total runout
RE: A quick question on total runout
Powerhound, GDTP T-0419
Production Supervisor
Inventor 2008
Mastercam X2
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II
RE: A quick question on total runout
Thanks for your answers, it comfirmed what I thought was the case.
RE: A quick question on total runout
Powerhound, GDTP T-0419
Production Supervisor
Inventor 2008
Mastercam X2
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II
RE: A quick question on total runout
I've specified a straightness tolerance on the tube axis of 0.2mm diameter. The tube axis is the datum and runout is relative to that datum.
RE: A quick question on total runout
Powerhound, GDTP T-0419
Production Supervisor
Inventor 2008
Mastercam X2
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II
RE: A quick question on total runout
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: A quick question on total runout
Believe it if you need it or leave it if you dare. - Robert Hunter
RE: A quick question on total runout
I believe that an axis is by definition straight.
I think what you are attempting to control is the 'derived axis' per the committee. NOt sure whether or not the proper method used.
RE: A quick question on total runout
RE: A quick question on total runout
Your part could have zero runout (perfectly straight centerline and circularity) but be too large or small diameter. Your part could have perfect nominal diameter everywhere but be bent so that it has excessive runout.
http://www.EsoxRepublic.com-SolidWorks API VB programming help
RE: A quick question on total runout
If I specify a dimension eg 10mm +/- 0.2 then when it comes to QA inpection any measurment between 9.8 and 10.2 is acceptable. However what I have been having are variations in the diameter depending where that feature is measured, could be 10.1 at one end and 9.9 at the other - still within spec.
It may be the manufacturer but the previous issue of the drawing had a GD&T paralell tolerance on that diameter and that didn't cure the problem, and we're talking over a length of 25mm.
Rant over.
Any other suggestions of alternatives to Total Runnout?
RE: A quick question on total runout
First off in this case when dealing with a diameter, Total Runout controls simultaneously form (cylindricity), orientation and location of all surface elements of the diameter relative to the datum axis. It does not control size!
You say in a subsequent post that
"I'm having problems getting a tube manufactured without variations in a diameter making assembly more difficult than it should be, the diameter varied depending on where you measured the part, but still within the specified tolerance band."
So what you are describing as the issue during assembly is the actual local size measurement of the component. Perhaps the specified feature of size tolerance range is your problem here and it has nothing to do with form, orientation or location.
Please clarify so that we can best assist you.
RE: A quick question on total runout
"the drawing had a GD&T paralell tolerance on that diameter"
Parallel to what?
Believe it if you need it or leave it if you dare. - Robert Hunter
RE: A quick question on total runout
Yes, you are mistaken. Runout is independent of actual diameter. Runout is a measurement of the "wobble" of a revolved surface.
Picture a bent or bowed rod of perfect uniform diameter.
RE: A quick question on total runout
The part is used in an assembly where a copper coil is wound around part of the 10mm diameter, so it doesn't have to fit into anything.
Variations in the diameter along the length of the feature cause problems getting the coil to operate within spec. The result is the coil winding company spends time re-measuring the part to confirm the best place to wind the coil.
The dimensional tolerance of the part is chosen to meet the requirements of the coil, it is the variations in diameter along the length of the feature that is causing problems.
If I was to use only a dimensional tolerance I would be looking at 10 +/- 0.025mm and that will be getting expensive
RE: A quick question on total runout
RE: A quick question on total runout
Here's an example: You have a shaft of Ø10 ±0.5. You need outer surface to vary only within 0.1 band, but the size tolerance is larger. Applying a cylindricity of 0.1 would accomplish this. Your size tolerance is large, but the amount of variation along the entire length of your cylinder is restricted, i.e. you could allow variance of Ø9.7 to Ø9.9 or Ø10.3 to Ø10.5, but you could not allow variance larger, like Ø9.7 to Ø10.3.
In application, cylindricity is a little more involved, but it accomplishes your goal. You may still be able to use runout in a similar fashion, but keep in mind that there are differences.
RE: A quick question on total runout
Hope this helps.
RE: A quick question on total runout
I'm off to buy a GD&T book....
RE: A quick question on total runout
MacomMech,
I have some slightly used GD and T books for sale. Reasonable. Is there a way we could hook up?
RE: A quick question on total runout
Ringman where are you based, I'm in sunny Glasgow UK.
RE: A quick question on total runout
I can't remember if this is one of the areas ISO (hence British Standards) differ from ASME Y14.5 but seeing rule #1 referenced made me think.
I believe most of the above posters work to the ASME specs.
KENAT, probably the least qualified checker you'll ever meet...