Marking sheetmetal

"Ernest Christley" wrote in message m...
: RST Engineering wrote:
::
: I *BEG* your pardon? In my part of the world, 0.0 is within 50 mils, 0.00
: within 20 mils and 0.000 within 5 mils.
:
:
: I have only a couple measurements on my set of plans that call for a
: specific tolerance. One is for the pins locking the gear leg halves
: together. The other is for the wing lock pin. The rest are just
: measurements with the smallest being with 1/16". Everything broken down
: into feet, inches and fractional inches. But no "plus or minus"
: anywhere. So I asked a recently retired machine shopman and sheetmetal
: worker, because, heh, if you can't trust somebody that's been doing it
: 40yrs, who can you trust? He told me 1/32" if not specified. Does the
: difference come down to how the numbers are specified? Fractional
: inches resolve to 1/32, and decimal inches have the tolerances you state?

Where I work , unless otherwise stated, we tolerance to:
Fractions ±1/64
0.0 ± 0.010 (10 mils)
0.00 ± 0.005 (5 mils)
0.000 ± 0.001 (1 mil)
We do make assemblies where we hold clearances of 50 micro-inches (µin) (Oh no, not another one!)

Blueskies, you and I are in the same world. When something finished product
is only six inches long with 4 bends and four corner notches, if you can't
hold ten mils your product looks like it was built with Bondo.

As for Mr. CHristly's measurements (and I'm glad he likes the little box; we
sure sell a hell of a lot of them) when he doesn't have the original
dimensioned print in front of him, and is making measurements with
envelopes, how he can say a measurement is off by so many mils without
knowing what it is SUPPOSED to be is beyond me.

If he is referring to the corner gap, I just went out and looked at a sample
of 10 from the last batch of 100. THe corners are water-tight to the point
where I can't see sky through them. How he has a 30 mil gap in his is
somewhat of a mystery.

Jim




".Blueskies." wrote in message
...

"Ernest Christley" wrote in message
m...
: RST Engineering wrote:

Where I work , unless otherwise stated, we tolerance to:
Fractions ±1/64
0.0 ± 0.010 (10 mils)
0.00 ± 0.005 (5 mils)
0.000 ± 0.001 (1 mil)
We do make assemblies where we hold clearances of 50 micro-inches (µin)
(Oh no, not another one!)