[PSUBS-MAILIST] O-ring groove machining

[Alan via Personal_Submersibles]

Am cutting some small o-ring grooves in aluminum, 3.4mm x 2mm deep for
a 2.5mm D o-ring. ( 10th of an inch) What is the best way to remove the sharp 
corners of the grove? I have read that you can spin your work in the lathe
& sand with 200 & then 400 grit sand paper. Is this right?
Have been having fun making the tool for this & don't think I have done a 
good job! Am I best to buy a carbide tool specific for this job.
Thanks, Alan

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