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(OP)
Dear friends,
What it exactly means "finishes=125; tir=0.005"; I saw on the drawings.
I am an non english reader.

Thanks   

RE: Ask for Term

lly,
In my experience what this means is that the surface finish is called out to be 125rms with a +/- .005". There is a gauge to measure this which most of the machine shops do have. In short this means that they want a fairly smooth surface finish, I believe this is standard for many valve seats. Hope this helps.

RE: Ask for Term

125 probably means 125 µin RMS.  (Microinches root mean square)

TIR is total indicated runout.  It is measured by rotating the cylindrical member and measuring the runout using a dial indicator.  It can be rotated either on precision centers or v-blocks.  There are pluses and minuses to each approach.

RE: Ask for Term

butelja,
Thank you for that correction, I have dealt with this before, it has just been a while.  

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