[Rhodes22-list] Reply to Mark Putnam about Motor Mounts

[Rob Lowe]

Ed/Rummy,
I'm not sure cutting the plywood differently would have mattered much.
Plywood is strongest in shear or compression, but lacks strength in tension,
bending, and has poor "punch (or pull) through" strength.  Not sure how the
motor is installed on this backing plate, but I'm guessing the plywood
started to bend and then the adhesives would pop loose.  The steel plate you
added resists the bending forces.  I like the idea of using plastic or solid
metal.  Either way, we see the importance of having a safety cable. - rob

----- Original Message ----- 
From: <R22RumRunner at aol.com>
To: <rhodes22-list at rhodes22.org>
Sent: Tuesday, November 07, 2006 9:12 AM
Subject: Re: [Rhodes22-list] Reply to Mark Putnam about Motor Mounts


> Ed,
> Thanks for finally posting. I've been thinking about your problem and I
> believe I know why the piece of truss snapped. In general trusses are made
from
> oriented strand plywood. I believe that if you had cut the truss
differently,
> say 45 degrees different, the grain would have been different and you
wouldn't
>  have been able to break it.
> I had some hair line cracks show up on my mount a couple of years ago and
I
> added a stainless steel backing plate cut to the same shape as the mount
for
> additional support. No problems with it since.
>
> Rummy
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