The aluminum billet version was getting expensive. The material
alone was $66. I know I just bought some today. I had to pay $16
just to have it cut to length.
Then I was having trouble finding suitable 10 mm 1 mm pitch metric
screws. I never found any I was completely satisfied with.
Making our
own was getting expensive.
The welded version can use the stock 10 mm 1 mm pitch bolts as it is
only .125 thick which can replace the stock clamping plate
The light really went on when I thought of welding the walls directly
to the steel spline plate.
No bolts or screws needed to bolt the spline plate to the coupling.
The spline plate is half the coupling.
Nothing could be easier or simpler.
The walls are rectangular .75" by 1.5" 4130 tubing from Aircraft
Spruce. I have some in stock.
There must be only three walls because there are six 10 mm bolts.
Here is what it looks like. It fits the stock 2 rotor flex plate but
does not stress it. All torque is transmitted by the six 10 MM
bolts.
I will weld one up and send it to you for testing Mark.
Paul Lamar
What amazed me is the coincidences. The rectangular tubing just
happened to be the right dimensions. There are only two choice's
from aircraft spruce. 3/4 by 1 1/2 is one of them. This leaves
plenty
of room for a couple of needle thrust bearings between the spline
plate and the gear box adapter plate.
BTW asymmetric rubber bushing might work out to be the best
configuration. Most of the rubber on the compression side. The acid
test will be the lowest engine RPM that does not cause resonance.
That does not mean it is not mitigating destructive torque pulses at
higher RPM's. The kind that shear bolts and pins.
Paul Lamar
Carrie Beasely was right. Powdered metal. I won't weld to powdered
metal. Back to 2 pieces 4130 sheet metal. Hard as heck. I ruined a
band saw blade on it. It came with all this stuff inside for $37.
Hack saw in the lathe does not work well.
Schabs Parts 12715 old plank road New Lenox Il 60451
Paul Lamar
This fixes the clitch. New 4130 welded sheet front coupling. The
4130
2.75" OD tube .120" wall
clears the big nut and keeps the rubber from getting chewed up
by it.
This is what I will build. No welding to the powdered metal
spline plate.
Separate 4130 front coupling weldment.
Paul Lamar
4130 heat treats itself to file hard in still air if over heated.
Do not
use abrasive saws to cut the pieces. Use a bit of oil and go slow
in the band saw and all is well. Welds in 4130 should be drapped
with ceramic cloth to cool slowly. Small parts dropped into a Lime
box (Metal) to cool slowly. In thicker sections think about
preheating
the pieces before welding and then cover to prevent local air
movement
from chilling the welded area. If a 4130 or similar part fails
right beside
a weld bead, it may have cooled to quickly.
You can salvage an abrasive cut piece by reheating to dull red then
standing in a Lime box until cold. Then you can use regular tooling
without damage. The Lime box needs a course screen above the bottom
to keep pieces from touching the bottom. Lime is a poor conductor of
heat, so cooling takes a long time. Never quench welds in water,
or with a wet rag. A good idea if you do not know the material at
hand
even if it turns out to be 1010 or 1020 steel.
Lynn E. Hanover
It was not 4130 I was cutting and ruined the saw blade.
It was powdered metal.
What does that do when you cut it with abrasive?
People tell me it can be welded but it has to be done exactly
right. I am not willing to risk doing it wrong.
BTW it is getting better. It deflected more than I expected before
it cracked. My guess is about 5%. I can see why it is getting
very popular in the auto industry. A very complicated part can be
mass produced very cheaply compared to machining it out of high
strength material.
http://www.pmdatabase.com/global/guidelines.htm
"Effect of Density the density of PM parts varies according to
the pressing pressure used. It is also affected by some of the
other processing parameters. It is important to recognize that,
in addition to mechanical properties, some key physical
properties are also affected by density. For example, elastic
modulus and thermal conductivity increase significantly with
increasing density; Poisson's ratio and thermal expansion also
increase, although more slowly. "
"Apparent Hardness * because of differences in structure, gross
indentation hardness values (Rockwell or Vickers) of wrought
metals and PM materials cannot be compared directly. The indenter
penetrates further into the porous PM structure, thereby giving a
lower hardness value than the intrinsic hardness of the metal
itself. Hardness values for PM materials, therefore, when
obtained on macro-hardness testers, are referred to as "apparent
harness" and represent the combined effect or porosity and the
metal particle hardness. For example, a heat-treated PM steel may
measure an apparent hardness of 30 Rockwell C while the actual
material measures 54–58 Rockwell C. "
Paul Lamar
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