Frame Shortening Tip
Date: Tue, 6 Oct 1998 12:17:26 EDT
I just read your outline re shortening a VW pan, and thought I'd pass along a
tip on aligning it that I read in a buggy mag a couple of decades ago. . . .
if you're interested. Being a Manx dealer, I was always on the lookout for a
better way to build the things, and this is one of the better tips that I ever
read. It sure beats all that measuring with a tape from corner-to-corner,
Before cutting, make three sets of exactly equal-length "X" or "cross" marks
on the frame, one set on top of the tunnel, and one set on each side of the
frame (I made mine on top of the raised channel that the body bolts to). Of
course, the equal-length marks must be made far enough apart and spaced so
that they will still be on the frame after the 14 1/2 inch section is
removed! The "taper" of the side channels will somewhat dictate the distance
between the marks, but I think 16 1/2 - 17 inches was about what I used. Also
scribe a center line on top of the tunnel. After cutting, pull the two frame
halves together, align the tunnel by using the scribed line, and tack-weld it
at the top-center of the tunnel. Then (with a jack centered under the tunnel
and spanning the two cut-lines) raise-lower the jack and shift the side rails
until all three pairs of marks are exactly equal again. It doesn't matter
what the distance is as long as all three pairs or sets of marks are equal.
Then tack the side rails, recheck the dimensions, and finish welding.
Being an engineer, you probably understand the triangulation principle
involved. The three marks, one being on a different plane from the other two,
assures alignment as long as the pairs of marks are exactly the same distance
apart before cutting and after cutting.
Pace (just outside Pensacola), FL