Bill Dube' wrote:

I put two hems on the top edges (instead of flanges.)

Dave McC replied:

Hi Paul and Bill,
On the original beam; instead of removing metal at the center for
flywheel clearance,  could you not roll the flange over into a hem in
this area, (or even the whole length) to provide clearance and still
retain the buckling strength?  Thereby avoid all these messy weldments
with their attendant heat affected zones etc. Love this stuff, BR Dave
McC

Paul Lamar replied:

4130 is not like mild steel. It must be bent with a generous
radius. It will be a long time before we make any more but
I am thinking about it.

Perhaps you've already thought of this: fold the existing flange over a
rod of appropriate diameter (to guarantee minimum bend radius), then
slide the rod out (since the flange/hem will spring back slightly,
thereby releasing the rod).  Of course, Bill will need to run another
stress simulation to see whether there are any issues. (But don't do it,
Bill, until Paul replies).

Russell Kent

Before we do any more of these things sometime in the future
I will need to confer with my friend with the NC press brake.
He has years of experience bending all sorts of metal.
I know just enough about it to know what I don't know :)

Paul Lamar

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