Alignment gage for seperated cylinder diameters.
Alignment gage for seperated cylinder diameters.
(OP)
I have an application where two seperated 1.000 x .475dia bored cylinders muct be within .005in TIR. The logical mechanical inspection technique would be to engage a snug fit gage pin into one of the cylinders and rotate the part on the gage pin with an indicator reading the other cylinder runout. Using a CMM is the a simple procedure but I would like to design an alignment pin gage. By taking the smallest toleranced cylinder diameter minus .0025in should represent the .005 TIR in theroy. Of course the actual design would not utilize the entire .0025in and also incorporate the cylinder diameter concideration. I am on the right track, correct?





RE: Alignment gage for seperated cylinder diameters.
What is the exact callout on those two bores? Does the print say "TIR" or is there another term or symbol used?
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
RE: Alignment gage for seperated cylinder diameters.
RE: Alignment gage for seperated cylinder diameters.
One cannot have a hard gauge for either circular or total runout. It must be checked with a variable gauge of some sort and a CMM also may not be appropriate since it only takes a number of readings about the feature.
I would probably use a divider head or chuck and chuck one of the features and zero it out at the end of the feature with a dial indicator. The axis is now set. In other words, you have created a datum. I am now contacting 100% of the surface rather than taking a few readings with your CMM.
Take your indicator (on a stand) and zero up at the lowest point on the circular feature. Rotate the chuck and record your TIR. Perform this measuring action in a couple of other spots and report your worst condition.
Again, one cannot have a hard gauge with a TIR call out.
Dave D.
www.qmsi.ca