Tonight I built a tool for checking front end alignment. It's pretty primitive, but it's pretty cheap, and it works. I did not take any digital photos. I can if you'd like, but I will try to explain it so you can duplicate it if you want.
It consists of 6 pieces:
4' of 1/2" EMT (Thin walled conduit)
4' of 3/4" EMT.
A compression spring that will fit inside the 3/4 conduit, but not nside the 1/2" conduit.
A hitch pin clip (Overgrown hair pin)
2 end pieces to plug the ends of the conduit
The two end pieces I made from aluminum. I turned them both down to approximately the OD of the 3/4 conduit. I turned down 3/8" of it to fit inside each of the two sizes of conduit. The other end, I turned to a point at an 80 degree angle. I tried 90, but it was too fat, so I sharpened it a little. If you do a good job of turning, you can press them down inside the conduit for a good tight fit. If you're like me and do a poor job of turning them, you might have to pin them in place. If you don't have a lathe, don't worry, you could make these pieces from wood on awood lathe, or even carve them. They just have to fit in the ends of the conduit and the points need to fit between the tire and the edge of the rim. Note that the very end should not be a sharp point. Round it over a little to keep from damaging the tire.
My spring was rather short and stiff, so I was afraid I would need some adjustment to do various cars. For this, I drilled several holes at 1/2" increments through the 3/4" conduit near the plug end. The hitch pin clip goes through one of these holes. Next put the spring inside the 3/4" conduit. Let it slide down against the hitch pin clip. Next slide the 1/2" conduit inside the 3/4" conduit. Now you're ready to go.
To use it, place one pointed end plug on the tire bead where it meets the rim on the back side of the tire, just below the radius rod. Compress the spring and put the other end in a similar location on the other tire. Adjust the hitch pin clip as necessary to get the spring tension right. Once you get it on the car, measure the distance from the end of the 3/4" conduit to the back side of the end plug on the 1/2" conduit. Make note of this measurement. Roll the car to the rear until the tool is on the front side of the tires. Make the same measurement again. This one should be 3/16" to 1/4" less than the first measurement.
Yeah, I know that just below the radius rod is not exactly the farthest point aft on the tires, but it's dang close. Also, the book says to make the measurement on the felloe, but my position is easier for the tool to stay on. Helps make up for the discrepancy of the radius rod thing too. If you want to be EXACT, you can calculate the differences and compensate, but I'd bet this is close enough.
If you intend to use it all the time, you might want to make a scale and an adjustable pointer to keep from having to measure and subtract. Just zero the pointer on the scale and read the toe in directly.
This photo shows the 1/2" counduit inside the 3/4 conduit and the plug in the end. Leaving the plug as large as the 3/4 conduit gives a good surface to measure against.
This photo shows the hitch pin clip through the 3/4" conduit which holds the spring in the proper location for my front end.
This photo shows the tool installed on the truck.
This one shows how the plug's point fits in the groove between the tire and rim.
Excellent tool, Hal!! Makes adjusting the toe-in a one man job.....something I need. Even my Model A buddies could out of the ditches with this tool!!
That looks like a good tool. I am too lazy to make one, however my method takes two people. I use a tape measure from Felloe to Felloe. It isn't that precice a measurement as the adjustment is one full turn. I just use the first turn of the tie rod end that causes the wheel to toe in instead of out. Any other adjustment would take bending a part.