Checking Nail Axle Run-Out

I have built scout cars for a while and have always used the straightest nails I can find to polish. However, when I recheck the run-out a second and third time, I keep getting different results.

I realize this is because I don't have a good way to accurately check the run-out.

I use a dial indicator on a stand and have chucked the nails up in just about everything I have with a chuck on it. Dremel, another Dremel, miniature imitation Dremel, Drill, wood lathe.

I am looking for suggestions on an accurate way to check the run-out on a nail.

 

Do you have a tuning board? Every BSA axle has runout. It’s important to get the bend pointed straight up. I tune my rear axles by giving them a small twist and seeing how fast it goes down my tuning board.

 

I do have a glass tuning board and I will try your method.

 

You’re going to drive yourself nuts trying to find axles with no runout. Like Reece said, twist them when tuning to find the best combination. If you’re going to choose the best three, measure them with calipers and see if you can get ones that are bigger in diameter. The best scout axles are probably about 0.088in Most end up being 0.087in.

 

I don't expect to find scout axles with no runout. I just want to know where the high point is so I can understand the results I am getting from the test track. I can use the 16-position rear axle test to get the best results, (or the tuning table method above that I haven't tried yet) but it is important to me to understand what the reason is for that position performing the best. If getting the 'bends' all turned straight up is the answer, then knowing where the high points are is an advantage. After I posted the question, I went down and drilled an additional hole in the wheel runout jig for an axle nail and turned the nail with my axle plier against the dial gauge. As primitive as that is, it does seem to give repeatable hi point information.
I know the larger diameter nails are best and I am working to improve my axle polishing procedure also.
We turn in two cars tomorrow for this year's Pack race. 3/5/23

 

If you have a hobby drill press, chuck up the axle run it on slow. You can see it.
Sometimes you run across a race that won’t allow bent axles or wants 4 wheels touching & the bad ones can come in handy. Just sayin