6061-T6511 - Dimensional and Flatness Tolerance
 

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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6061-T6511 - Dimensional and Flatness Tolerance
 

"Bob La Londe" wrote in message ...

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

Does this help?
https://www.mkmetal.net/images/uploa...0Tolerance.pdf

6061-T6511 - Dimensional and Flatness Tolerance
 

On 2/21/2021 1:25 PM, Jim Wilkins wrote:
"Bob La Londe"Â* wrote in message ...

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

Does this help?
https://www.mkmetal.net/images/uploa...0Tolerance.pdf




It could. Thank you.

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6061-T6511 - Dimensional and Flatness Tolerance
 

On 2/21/21 1:11 PM, Bob La Londe wrote:
I've bought 6061 T6511 from several vendors.Â* Is there a spec I can look
up for what what should be considered acceptable?

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

2.Â* One has certain sizes that are from 0.003 to 0.050+ over size, but
mixed.Â* Some a little over.Â* Some a lot over.Â* 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.Â* 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.Â* That was a long time ago, and it was easier to
just stop buying from them at the time.Â* 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.Â* 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.Â* I didn't quit buying
from, but I don't buy much from them due to price.Â* 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.Â* "Bring in the right size stock?Â* 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.Â* 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.Â* 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.Â* O/+ seems like it would be acceptable, but (-) I
would not think should be at all.Â* Its shaving pennies off value to
increase profits.



Just as one comparison point McMaster Carr shows a thickness tolerance
of +/- 0.009" for 1/2" x 6" x length extruded 6061-T6511 in both sheets
and bars. No mention of flatness, just "all other tolerances ASTM B221".

--
Regards,
Carl

6061-T6511 - Dimensional and Flatness Tolerance
 

On 2/21/2021 3:13 PM, Carl wrote:
On 2/21/21 1:11 PM, Bob La Londe wrote:
I've bought 6061 T6511 from several vendors.Â* Is there a spec I can
look up for what what should be considered acceptable?

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

2.Â* One has certain sizes that are from 0.003 to 0.050+ over size, but
mixed.Â* Some a little over.Â* Some a lot over.Â* 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.Â* 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.Â* That was a long time ago, and it was easier to
just stop buying from them at the time.Â* 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.Â* 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.Â* I didn't
quit buying from, but I don't buy much from them due to price.Â* 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.Â* "Bring in the right size stock?Â* 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.Â* 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.Â* 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.Â* O/+ seems like
it would be acceptable, but (-) I would not think should be at all.
Its shaving pennies off value to increase profits.



Just as one comparison point McMaster Carr shows a thickness tolerance
of +/- 0.009" for 1/2" x 6" x length extruded 6061-T6511 in both sheets
and bars.Â* No mention of flatness, just "all other tolerances ASTM B221".


I always forget McMaster Carr for stuff like that. They are a great
information resource.



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