I've bought 6061 T6511 from several vendors. Is there a spec I can look
up for what what should be considered acceptable?

1. One consistently provides out of flat stock. Sometimes more than
..015 across a piece of 1/2x6 flat bar. (ACROSS)

2. One has certain sizes that are from 0.003 to 0.050+ over size, but
mixed. Some a little over. Some a lot over. I can't grab two bars and
cut them to length and use them together even for rough work unless I
also size them on all dimensions.

3. Another sent me some stock that is from .005 to .01 under size on
all dimensions.

I mentioned the problem to number 1 and they said its within spec and
sent me a spec number. That was a long time ago, and it was easier to
just stop buying from them at the time. Other vendors did not provide
stock in the same sizes warped to the same degree.

I also asked about the huge stock size variance from number 2, and they
said I should just machine it to size. They are partially right, but I
due a fair amount of work that doesn't need all six sides machined if
the stock is nominally close to the same size. I didn't quit buying
from, but I don't buy much from them due to price. Also instead of
stocking or bringing in a requested size stock for me they want me to
buy larger more expensive stock and just machine off and throw away the
rest. "Bring in the right size stock? No just buy bigger and throw
away 25% of it."

I have not said anything to number 3, but I recently tried to run some
stock in a pre-made fixture plates and found myself having to add shims
to my edge clamps to hold the stock. They are an order of magnitude
better price than number 1 or 2 and have the best overall selection.
All of the stock I have gotten from them has decent flatness. I still
would like to continue buying stock from them on a regular basis, but
I'd like to know what the spec is for 6061-T6511 acceptable dimensional
accuracy before I say anything. O/+ seems like it would be acceptable,
but (-) I would not think should be at all. Its shaving pennies off
value to increase profits.


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