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True position on a hole with a basic angle and basic length location

35 Dodge

Plastic
Joined
Jan 15, 2008
Location
Claremont, NH
I would like to know what the correct method of checking true positon of 6 equaly spaced holes that are drilled radial. The first hole is centered on the print the second hole is 60° basic to it. There is a basic length location of .225 from Datum B which is a plane. The hole size is .025 +/-.002. the feature control frame states true position, with a cylindrical tolerance zone, .035 tolerance, to Datums [A]. Other than using a CMM how could I go about inspecting these features. What I have is gauge pins a vision system and a comparator to use.
 
Can't answer that without some missing info. Is the baseline of the angle (i.e., zero degrees) parallel to datum A through the center of the first hole? Does MMC or LMC apply, or is the tolerance regardless of feature size?
 
Yes the baseline of the angle is parallel to datum A and goes through the center of the of the first hole. Also it is regardles of the feature size
 
35 Dodge, I don't know if you got an answer or figured this out, but without seeing a sketch or drawing, it's hard to tell exactly what you have. I am picturing a flat round disk, with or without center hole, with six holes drilled into the circumferential edge at 60-degree increments. I imagine the datum A is the diameter, and datum B to be one flat side or the other. Assuming this is close to your reality, My choice for your task would be the comparator and a proper reticle for angle measurement for the 60 degrees, using pins stuffed into the holes. I will note that the .035 tolerance you indicate is about like pushing a radio flyer wagon through an airplane hangar door tolerance-wise. You could almost eyeball that level of error and know that the part is OK, depending on the scale of the part and other features, of course.
 
Go online to the "Tool and Die Guy". He has a series on layout and measuring that I believe will answer your question. I would try but probably mess it up as I may be slow, but eventually I do get the job done!
 








 
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