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Sent: 	Tuesday, May 13, 1997 10:44 AM
To: 	[log in to unmask]
Subject: 	FW: Acronyms



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Sent: 	Monday, May 12, 1997 12:01 PM
To: 	John Parsons; [log in to unmask]
Subject: 	RE: Acronyms

"TIR" stands for "total indicated runout" or "total indicator runout" on a 
drilling machine. The measurement is usually made by inserting a precision 
measuring pin into the chuck and measuring runout using an indicator gauge or 
dynamic measuring device [such as those manufactured by Lion Precision]. The 
measurement is generally done at 1/2" or 3/4" from the nose of the chuck, and 
if the measurement is dynamic, then the rpms at which the measurement is taken 
is generally given. Runout of the spindle shaft is sometimes measured, but 
since this measurement does not take into account the effect of the chuck or 
collet, the more common practice is to measure runout using a masuring pin. 
There is a fair amount of literature on the subject, such as IPC technical 
papers: IPC-TP-774 ["Dynamic Measurement of High-Speed Spindle Runout" (1989)] 
and IPC-TP-844 ["New Developments in Dynamic Spindle Runout Measurement" 
(1989)]. If you would like additional information or publications on the 
subject, please let me know.

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From: 	John Parsons
Sent: 	Monday, May 12, 1997 2:57 AM
To: 	[log in to unmask]
Subject: 	GEN: Acronyms

Good Monday Morning,

I am looking for the full meaning of the following acronyms:

NEMA

TIR (with respect to true position dimensioning)

Thanks

John Parsons




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