Why out-of-round holes?
Why out-of-round holes?
(OP)
We're finding some bores in our parts aren't very round (as measured with a 3 point bore gage). They are 1.125 Dia x .375 dp in aluminum. The bore diameter varies by .005. I'm surprised this could happen as the bores are made with a boring head on a mill. Has anyone seen this before? How could they be so out-of-round with a boring operation?





RE: Why out-of-round holes?
RE: Why out-of-round holes?
Manufacturing Freeware and Shareware
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RE: Why out-of-round holes?
What size is the bit?
What are the feed rates?
Or any other information about the tooling.
RE: Why out-of-round holes?
RE: Why out-of-round holes?
It could be the aluminium is not that stable and “moves” after the bore is finished, maybe a finishing cut on the bore as the last operation (if practical) would solve the problem?
RE: Why out-of-round holes?
RE: Why out-of-round holes?
"I think there is a world market for maybe five computers."
Thomas Watson, chairman of IBM, 1943.
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?
RE: Why out-of-round holes?
RE: Why out-of-round holes?
RE: Why out-of-round holes?
RE: Why out-of-round holes?
RE: Why out-of-round holes?
If a spindle has enough play in it to cause a finishing cut on a bore to be .005” put of round then it should be in a scrap yard.
Boring is far more accurate than reaming, if a spindle has that much, the reamed hole will be a real mess.
RE: Why out-of-round holes?
Neither do I.
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RE: Why out-of-round holes?
RE: Why out-of-round holes?
Scott
RE: Why out-of-round holes?
RE: Why out-of-round holes?
This is a good lesson in resolving problems if something has been working and quits all of a sudden. The first question always is "Has anything changed?" and push for answers.