Monday, December 6, 2010

Adjustable chassis supports fabricated

The last week has been annoyingly lacking in productivity due to unmerciful and tactless intrusion of the “day job” into my Boss restoration play time.  The nerve!
Anyway, I did manage to fabricate a pair of chassis supports that will allow removal and replacement of the cowl panel assembly with the car in the rotisserie.  Now, these rather rudimentary creations are far from stylish, but they should work quite well for the relatively short time they will be required.  Further to that, I made good use of a spare basement jack post I had kicking around.  I figured if it could hold up the floor of a house, the Mustang body would be no sweat.
The idea in all of this was to use the spots formed into the lower torque box area known in certain circles as the “buck” pad locations.  These are flat pockets formed in the chassis where the lower pieces of the unibody structure are located in the body “buck” as the car starts to take shape along the production line.  These points are generally strong and flat and make good places to support the body when doing work like this.
The first step was to make some simple wooden “shoes” that fit the contours of the buck pads neatly.  Then it was a simple matter of measuring to the ground on both sides, adding the measurements together and dividing by two to get the exact length each post would need to be.  Of course, one side could be fixed length and the other made with the screw adjuster to add a bit of preload.  I cut down the width of the mounting plates to match the wooden shoes and welded one to the top of the fixed tube (driver’s side) and the other to the top of the adjuster screw.  Normally, these plates just sit on top of the post/adjuster screw.  However I felt it better that they were welded to ensure a small margin of safety.  This presented a small challenge where the top of the adjuster screw was concerned, but the solution I came up with was to weld a large washer to the top of the screw pilot.  This allowed the plate to be retained securely, yet still allow the adjuster screw to turn freely.  Simple and effective.
To the bottom of each post, I welded a 7” long piece of 2.5” square tubing to act as a stable “foot” for each post.  Once all the welding was done, I simply screwed each mounting plate to the wooden shoes and set each post in place.  With a little twist of the adjusting screw, the body firmed up quite rigidly in the rotisserie and I can now move toward the task of replacing the cowl and addressing the firewall, inside and out.
Diver's side wooden "shoe" fitted to buck pad.

Passenger's side shoe with jack screw.  Easy to adjust preload with an adjustable wrench.

To keep the adjuster screw freely rotating within the mounting plate yet still secured, I welded a large flat washer to the top pilot of the screw in the location indicated.  This allowed the freedom of movement that was required and the security of a welded assembly.

I added a broad 2.5" square tube "foot" to each post.

It ain't pretty, but it seems to work just fine.

1 comment:

  1. Good solution Sven! I love re-purposing things like that. :-)