In a message dated 04/02/2009, rog@.......... writes:
<=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>8020 is=20
6061-T6 aluminum in an extruded erector-set like form that seems to be a=20
standard. This type of extruded aluminum seems optimal for stiff=20
seismometer like structures. It is easy to configure and quite=20
inexpensive as well.
ht=
tp://www.automation4less.com/store/categories.asp?cat=3D1116=20
I am curious if others have used 8020 in seismometer=20
designs.
Hi Robert,
You would need to use the larger sections, but=20=
they=20
may be relatively expensive. You need HT30 triangular plates at the corners=20=
to=20
make the structure rigid enough. Aluminum is ~3x as flexible as steel. The E=
Q1=20
used 1.5" square from memory.
I prefer standard U channel, 3" x 1" x 1/8" for=
a=20
Lehmanm and 2" x 1" x 1/8" for an AS1 type vertical. These work fine.=20=
The=20
corner plates are cut from 5" squares. I put the open U on the inside of the=
L=20
frame.
I use Stainless Steel nuts bolts and washers. I=
f=20
you put mild steel or brass in contact with Aluminum, it corrodes very=20
rapidly.
I suggest that you cross check the material pri=
ces=20
and let us know?
Regards,
Chris Chapman