[200q20v] Re: 200q20v digest, Vol 1 #73 - 14 msgs

[Bernie Benz]

George, If I may critique your message (butt in) with my .02:

First, I assume that your message refers to the fab and implementation of my
"Benz Brace" strut to strut brace design on your 200.

> From: George Sidman <sidman at montereynet.net>
> Date: Wed, 07 Mar 2001 11:30:37 -0800
> To: 200q20v at audifans.com
> Subject: [200q20v] Re: 200q20v digest, Vol 1 #73 - 14 msgs
> 
> Dale:     I believe this little project has a lot of
> promise, and I am interested. Naturally, I can't help but
> fiddle with the engineering, and have a couple of thoughts.
> In the interests of keeping this simple, however, you may
> want to ignore these ideas, and proceed as planned, in which
> case I remain interested.
> 
> 1.    It seems to me that if the clearance is available between
> the hood and strut, that making the neck of the nut about
> one half inch longer, with a spacer, no notching would be
> required of the washer or across the plenum. I will check
> the space available and report ASAP.
Why risk strut rod failure at the main rod to threaded diameter, the sharp
internal radius at that transision is prone to bending stress failure and
your idea will unnecessarily increase this stress.  Further, there is no
good reason not to knotch the the cupped washer, as it has no usefull
purpose, short of keeping the strut from falling out of the tower should
rubber bushing disinergrate in full rebound condition, equally well
acomplished by a knotched washer.  Keep the brace as low as possible.
(Gotta watch these EEs all the time!)
> 
> 2.    EMT is aluminum and not very strong, either in flexing or
> resistance to crushing at the jam nut. I intend to use a
> stronger steel tube, and weld the rod end at one end.
> Insofar as Bernie's solution works only in compression, it
> seems that getting a more positive grip at the adjustable
> end would strengthen the installation in both compression
> and tension, possibly reducing the metal fatigue which
> appears to eventually introduce the crack. I will research
> the parts to get a threaded adjustment which is
> bi-directional positive.
Stick to silicon.  Apparently, you don't know your mechanical materials.
EMT is Zn plated steel.  Inasmuch as all steel has the same modulus of
elasticity, there is nothing to be gained with a stronger steel.  Why weld
the tube at one end?  I guess to save the cost of one jam nut.  Good idea!
but just leave it off, without welding.  How could welding just one end add
strength in tension?  The nature of the type 44 chassis is that of excessive
negative camber.  The brace will never see tension if you do your camber
alignment correctly.

Rather than over engineering an optimum design (IMHO), do a simple worst
case compressive force calc for the brace.  You'll find that it is in the
order of 200 lbs.  No big deal.  No need to guild the lily!

Bernie
> 
> Fun Stuff, and probably a very good and inexpensive addition
> to a well appreciated car.............
> -- 
> George Sidman, President
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