Does anyone have one of these? A friend loaned this device to me.



The instructions are moth eatten, but can be understood. The kit is missing something call the 20 degree folding gauge. From what is left of the pictures, this gauge looks like two pieces of sheet metal that are hinged. The edge of these plates are cut at a 20 degree angle. The gauge is used to set the wheels so that the angle of the wheels can be measured. I'd like to get the deminisions of this gauage so that may be a new gauge can be made. Also, has anyone had any experience using this thing? It appears that the two cast iron spindle adapters connect to the spindle bolt and the level slips into one of two drilled holes of the spindle adapter. Then by moving the wheels 20 degrees and measuring the angles, the caster, camber and king pin inclination result. Thanks
Mike

I have a much later set of Weaver gauges that my step dad used when he did alignment. Usually the camber is simply a measure of the angle of the spindle bolt with the wheel aimed straight ahead while the caster is measured by first turning the wheel hard to one direction at a specific angle (it was measured on a ball bearing plate that the wheel sat on in my dad's alignment shop) and then setting a level bubble to a zero setting. Next the wheel would be turned in the opposite direction hard to the same angle on the ball bearing plate. The caster is then read on a calibrated scale that compensates the caster angle measurement for the wheel turn angle. If possible to turn the wheel 45 degrees in each direction then the caster would essentially be the angle difference between each of those extreme settings since they would be 90 degrees apart. If you think it through you will see how this can work. Hard one way tilts the spindle inward at the bottom while hard the other way tilts the spindle outward at the bottom and the caster is the difference between those 2 angles but corrected for the amount that the wheel was turned left and right with regard to turning position angle. I probably have not explained it very clearly but I could demonstrate it on my dad's Weaver gauges if someone was watching. I suspect this device works on the same principle.

I think I understand. The gauge plate that is missing is the device used to swing the wheel in and out the same amount. I would think that this is rather subjective. Must have been difficult to get the wheel to swing exactly the same amount both ways.

I was thinking about this in looking at mine Mike. You're right with the angle plate being subjective. A workaround would be to attach a laser level to the rim and aim it at the wall. Figure out the math on how much lateral swing 20° will be for the distance from the wheel to a wall and mark that spot off from 'straight-ahead'. Then go on with the normal checking.

Garnet

Garnet:

It isn't totally subjective in that the angle must be the same in both directions and then the measuring device (usually a bubble level on a scale) has to be calibrated in units that correspond to the total angle. The wider the angle the greater will be the movement of the bubble and the corresponding scale markings must be calibrated for the angle used in the measurements. I recall BEAR brand ball bearing wheel plates had the angle and pointer to it clearly marked in each direction. I think it was something like 30 degrees but very nearly the maximum that the front wheels would go in each direction. BEAR gauges were calibrated to this angle but Weaver gauges used the same angle since I know my dad used both of these gauges interchangeably. The Weaver was easier to use since it was fastened to the end of the threaded axle just behind the front wheel nut while the BEAR gauges had to be placed against the edge of the rim at top and bottom so it was necessary to also find the true part of the rim for the gauge to rest against. This BEAR gauge also had to have its height adjusted for the rim size height. I remember watching my dad set the alignment on many a car, truck, and even school buses. THe ball bearing wheel plates are a must or the front wheels will not be fully relaxed and you will get erroneous readings. Moving the car ahead and then back to relax the spindles and bearings would also do the same thing when doing the wheel alignment with a home brew garage setup.