Re: [CAD_CAM_EDM_DRO] Hot rolled router frame: added note

I had previously mentioned using ASTM A-500
welded tubing... but it was either ASTM A-513
(hot rolled) or A-500 in a stress relieved grade.
It was dark with mill scale and had seen some heat.
I had only specified "hot rolled welded tubing".
Anyway, it had some residual stress- particularly hoop.

One other thing might be considered: A-500 and
A-513 can be had in stress relieved grades, although
i'll bet it is expensive. It might be cheap to do heat
treat on the sticks BEFORE assembly, but I still
would not blanchard one face only without using
Tacked on 1018 pads or something. Grouted on pads
as I and others use are even better in my opinion.
There are pictures and descriptions on my engineering
web site. Virtually no machining is required, and the tubing does not have
to be straight.

I did look up the straightness spec: it is 1/8" times
the length in feet divided by 5. So a six foot piece
would be within 6/5 x 1/8 = 0.15".

I
Leslie M. Watts
L M Watts Furniture
Tiger, Georgia USA
http://www.alltel.net/~leswatts/wattsfurniturewp.html
Engineering page:
http://www.alltel.net/~leswatts/shop.html
Surplus CNC for sale:
http://www.alltel.net/~leswatts/forsale.html