How much of my spline should be showing?

More specifically people will ask "How much of the blue should be showing?". The blue doesn't matter, it doesn't always start in the same spot so you should really be looking at how much spline is showing. The answer though depends on the type of spline you have. For Tom Wood's drive shafts there are mainly two types of spline; the S spline and the X spline. If you have the S spline, there should be about 1.5" of the smooth bar showing. For the X spline, there should be about 2.5" of the cut spline showing. As long as you are within a half an inch or so of these numbers, consider your shaft a good fit. If the amount of spline you have visible is much more or less than what is recommended, you may need to have your shaft lengthened or shortened. Below are some photos that should be helpful.