The Lead engineer here has asked me to reduce the hole sizes for a few
components on our through hole designs. The component leads in question have
rectangular cross sections, and he has reasoned that if the hole is a bit
small we will get a "pressure fit". These components have been known to
"float", but up till now we just lived with it. I should mention that we
switched to new assemblers who use hand loading instead of auto insertion
for their through hole jobs.
        So my question is (were you beginning to doubt I had one?) how small should
I go so as to not break the fingers of the assemblers, but still getting the
"pressure fit" he wants? 0.001" of overlap? 0.003" of overlap? .005" of overlap?
If the holes vary by +/- .003" and the leads by … oh, I don't know,
.002"??…then could I expect nasty anonymous letters from disgruntled assemblers?

Oh yea, 2oz copper on a .093" 2 sided board, and a 1oz copper on a .062" 2
sided board.

It seems to me that I should be fine with a close fit, but with no overlap.

Any books or articles cover this kind of a situation?

Is the lead engineer off his rocker? (not that I would tell him, if he was ;)

Thanks,
        M. 
-------------------
Martin Spizman
 MEYER SOUND LABS
  (510) 486-1166
    [log in to unmask]

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