Here are a few pics of the caster fixture I use to do front end alignments. The beauty of this fixture is that you don't need turn plates to use it, as you are directly reading the caster through the center line of the ball joints. I use this fixture to set dirt track cars, road race cars, drag race cars as well as street cars:

You first need a piece of tubing that slips over the upper and lower ball joint studs. Measure the distance between the two ball joint nuts and cut the tube 1/16" smaller than the measurement:



The tubing now needs to be notched so that one end of the tube can slide over the lower ball joint stud once the tube is slipped over the top ball joint stud:



Cut a piece of 1/2" square tubing about 6-8" long:



The square tubing will be welded to the center of the tube. Make absolutely sure that it is welded 90 degrees to the round tube:



The cotter pins are removed from the ball joint studs and the fixture is slipped into place. Since it is slightly smaller, one of the ball joint nuts can be backed off to tightly hold the fixture in place. An angle finder is placed on the square tube extension, and you are directly reading the caster of the spindle:

 

Excellent!

I'm a little lazy so I would skip the welding part and use magnetic digital angle finder directly on your pipe.

I can measure caster directly on driver spindle but passenger spindle is to rough for consistent reading. If I ever have spindles out I will clean vertical for direct caster measurement.

 

just make sure the angle finder is perfectly parallel to the tire and the tire is parallel to the rear tires

 

That's brilliant! I think I may try that. I align my front end about 12 times a year using the Fastrax gauge. But this may save me some time. Thanx.

 

The way I understand this one, the upper and lower ball joint studs need to be the same size. Otherwise the tube won't be parallel to the bolt center axes. Being parallel to the outsides of different size studs is meaningless. Judging by the length of the tube, a 1/16" difference in stud size would result in about half a degree error. If there is a difference, and you know what it is, you can account for it with a little math, so it's not a deal-breaker by any means.

Otherwise I like it.


Norm