Drilling holes in steel tubing

On Fri, 30 Sep 2005 21:24:47 -0700, Smitty Two
wrote:

In article .com,
"wright1902glider" wrote:

If you're paralleling the tubes for six inches or more, and you filled
the notches between them top and bottom with a fillet of serious
industrial epoxy, (not the five minute stuff) I'd think you'd be able to
support more of a cantilevered load before the glue sheared, than you
would before the tubing folded at the bolt holes.

From a strenght issue, I agree; most adhesives I've worked with will
fail from the concentrated peel forces in an application like this.
What he wants to do is taper a wedge, probably of wood, over a few
inches so the load is unifirmly imposed. No, I cannot do a sketch.

(EMT isn't very
strong, and you're going to need a 0.187" hole for a #10 bolt.)

I want to see how hard he has to drive to get a 0.190" fastener (#10)
through a 0.187" hole ...

In reality, I agree with you. Most #10 are specifically on the low
side of tolerance so they can fit the 3/16" spec, and most drills
drill oversize.

Anyway, I can see you like the bolts. You could make your own clamping
fixture, a combination of the V-block idea and the two by four idea. If
you have a table saw, you could cut stepped grooves in two 6 or 8 inch
long wood blocks. The inner step has a width and depth of 1/2". The
outer step has a width of 1" and a depth of 1/2." Drill some holes for
drill bushings, available at the industrial hardware store, press them
in, clamp the two halves around the three tubes, and drill.

And leave the v-grooved blocks installed, extending past the fasteners
in the loaded direction.