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rick-l rick-l is offline
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Join Date: May 2002
Location: St Louis
Posts: 4,213
Originally posted by Tim L
I use the laser technique also. I think I can easily achieve that tolerance. The procedure I use is as follows:

1) I use a laser attached to a bar that rests on my rim edges. the bar has a relief to clear the hub. I use a simple bungee to hold it in place.

I thought WOW this is a great idea and I was playing with this last night.

I cut out a piece of plywood to put the level on and apply it the wheels (get the beam out beyond the fenders). Something was not working. The toe in was way off.

After thinking about it for a while I wondered if the laser came out of my $3 harbor freight level parallel to the base. I set a piece of I beam I have on the floor (parallel edges) and placed the plywood against the web and made a mark on the wall 10 feet away. I then flipped it to the other side of the I beam and made another mark on the wall. The distance between the two should have been the thickness of the I beam web + 2 * the plywood fixture + 2 * the height of the laser above the base. It was 2 inches off. I started sanding but now I don't have a square surface.

I think I'll go buy some aluminum and build an adjustable fixture.

edit: doing some geometry I am trying to adjust 100ths of inches. Maybe I'll make a calibration fixture, measure the error, and use the error in a spreadsheet.

Last edited by rick-l; 02-17-2007 at 10:48 AM..
Old 02-17-2007, 09:27 AM
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