Jerry, the 4130 box beams are almost done.  Here is a 4130 test
sample to check for spring back. The final version will
be perfect with 1.312 holes punched in the ends for the rubber
bushings.

My buddy George had to make a special tool.
George is not the cheapest guy in town so
you might want to make this up for your local supplier
when you reorder box beams. It consist of a 1/4 inch
steel plate with 1/4 round bar welded on the bottom and two 1/8
inch
doublers welded on the top so it fits the 1/2 inch tool clamp in
the CNC press brake. You should save your supplier some time and
money doing this for him.

On the other hand makes sure you included George (Talins in
Torrance
CA)
when it comes time to reorder. He already has the tool and knows
how to make them.


Paul Lamar

Looks good thus far.  By all means we should  stick with George
since
he knows how to do it.    What is the finished outside width?
Jerry

Knowing George it will be exactly like the drawing I gave him.

Paul Lamar

I admit that I have not been following this "box" beam thread very
closely,
but when you leave that slot full length, you no longer have a "box"
and
the torsional stiffness is almost zilch, and the buckling strength
severely compromised - Vance

Yes all true but there are no torsional loads to speak of. The bending
strength is higher than the 1-1/2 inch high hat section beam  Jerry
static
tested by supporting his pickup truck because it is now two inches
high.
Think of it as a two inch high hat section with the flanges bent
inwards
rather than outwards.

Never the less having said all that it is easy to beef it up by
capping the top
with a short length of flat 4130 sheet  outboard of the ring gear
slot. Namely directly
over the two bolts that fasten it to the engine and beyond a couple of
inches.
This is the area of the highest stress.

Jerry can also lower his pickup truck on this one as well.

Paul Lamar

No more truck tests.  I certainly will weld a  cap  over the bolts.  I
am assuming that the remaining .035  width will be shimmed out.   If
the box is exactly ,270 wide a piece of 2" .035 4130 will do the job. I
got my fingers crossed.  If necessary,  we can add a little extra and
have the beams ground.  What is the tolerance on the width?       Jerry

No shimming required Jerry. The steel bolt spacers are made on the lathe
to be exactly 3.050 long. Since the beam will be 2.70 wide that gives
you a corner  weld fillet on each end of the spacer (3.05-2.70) / 2 = .175 high or long.

The tolerance on the beam width is +/- .05 on the width but if I know
George it will be closer than that.

Paul Lamar
 
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