Re: [CAD_CAM_EDM_DRO] steel tubing strenght formulas ??

On 10/2/04 10:15 PM, turbulatordude wrote:

>One of my concerns is a 5 foot lenght and how much it will bend under
>cutting pressures.
>
>Does anyone know how to calculate this ? or is there software that is
>available ?

Here's a slightly more interesting calculator with examples:
<http://www.aps.anl.gov/asd/me/Calculators/ElasticBeam2.html>

The examples are in metric, but you can use inches and pounds. The
wikipedia gives a Young's modulus value of 30,000,000 psi for steel. To
get a moment of inertia for square tube, take (OD*OD^3 / 12) - (ID*ID^3
/ 12). For 2" square 11 gauge, that gives you moment of inertia of
.5518. Using case 4 (ends free) that gives you about 1/16" of
deflection for a 250 pound center load for a 5 foot length. That's
about what I came up with using my SOTP calculator.

If it was me, I'd add a good fudge factor and the understanding that
mechanical steel tubing is not entirely consistant in quality or
temper, even if you're buying it from the mill.

Hal Eckhart - Casa Forge - Minneapolis MN - <http://www.casaforge.com>