[T3] Type 1 to type 3 tow bar adpter

[dlstiefel]

On 2016-12-17 13:51, Jim Adney wrote:
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> Dennis,
> 
> Thanks for the video; now I see how your attachment was made to work.
> 
> A couple years ago, Gary Forsmo and a friend made up a fixture so
> that he could tow his Type 3 behind his RV coach. I helped them with
> the design and the work and it seemed to work quite well, although it
> was designed to work strictly with the towbar that also worked with
> his Honda, so it wasn't something that you could have used.
> 
> About a year later, and after towing that car to the NY Invasion,
> Gary's front axle beam suffered a rust breakdown that was unrelated
> to the towing but required replacement of the front axle beam. When I
> removed the beam I wanted to harvest as much of the old internal
> parts as possible, so this meant bandsawing the old beam into little
> pieces.
> 
> What I found was enlightening. We had similar U-bolts over the bottom
> section of the beam, but with better spreading of the U-bolt forces.
> Even with that spreading, the box section of the axle beam had
> collapsed as much as 1/4" under where one of the U-bolts rested.
> While this didn't affect the functioning of the axle beam or the tow
> bar, it pointed out that we were expecting too much strength from
> that steel. It just wasn't designed to be strong in that direction.
> 
> I gave Gary the cut cross section of the axle beam that shows the
> crushing. If he still has it, perhaps he can post photos somewhere.
> 
> In your case, you're also asking the lower pinch weld to take all the
> force of towing. I doubt if it will hold up. Keep in mind that the
> metal there is probably completely soft, made to be pressed into the
> 2 halves of the axle beam body. Plus IIRC the pinch weld isn't welded
> with a continuous weld, so you're likely to pop the spot welds.
> 
> One more thing: on Gary's car the left pan horn that comes forward to
> support the axle beam appears to have been bent slightly upward. We
> don't know if this is new or if it was long term, perhaps due to rust
> weakening. It's possible, however, that it was caused by the force of
> towing, which was, like your design, applied in a line below the
> support horns, so the towing force would have applied a torque to the
> axle beam and support horns.
> 
> Sorry to be a wet blanket, but I think you might want to know about
> these potential problems before you start your testing.

Oh no now that I think of it I think I based this idea for this on some 
photos Gary sent me a few years ago. Wow this is bad with all the time 
and effort we have put in it but thanks for the heads up. I thought the 
only problems he had was rust issues in this area. Since my car has 
spent all its life in Alabama I thought it would have this issue sounds 
like you are saying this metal is just a thin covering and not as thick 
as a T-1 beam in this area. Maybe I can come up with an idea to 
reinforce this like a thick steel sleeve that can go between the u-bolts 
and the beam or something. I hate to know we wasted all this metal and 
time. If you have any pictures of this damage I would like to see it. 
Maybe it would give me an ideal of a posable remedy to salvage this 
project.
-- 
Dennis