First off I wanted to use a DD shaft because they are easy to make and don't get beat up too easily. A 3/4 DD shaft from a GM vehicle is usually*** (but not always) a 0.750 inches diameter shaft with two flats cut 180 degrees from each other with a distance of 0.550 inches between them. This means the flats are 100 (thousanths) deep. Or 0.100 inches from the original radius. For those that don't want to weld bits together or use adapters from one shaft type to another, here is what I did... What you need: -3/4 round bar for steering shaft -Wood block (for a 3/4 shaft a good 2x4 is acceptable) the length of your flat. -Drill bit, 3/4 for a 3/4 shaft. -Small chunk of 3/4 DD shaft -Grinder with flap disk. I used a worn out 60 and 80 grit -A set of calipers, No need for the micrometer here -A good straight edge -Scribe -A Fine tooth file Cut off a chunk of wood a little longer than your flat needs to be. Now drill a 3/4 hole in it with a nice straight bit. No wobbly bits this time. Then cut off one end just into your hole. Both have been done here already. Now Jam it on the end of your scrap piece of DD. The shaft should be a very tight fit. Take your wood rasp or saw and get the wood close to level with one flat of your existing DD shaft. Then take a medium file and remove wood evenly and slowly till you are scraping the existing DD flat. The Key here is to go slow so your wood piece makes a nice straight pattern to work from later. Remove your pattern from the existing DD and put it on your 3/4 round bar. This should leave a small portion of the bar protruding from the wood pattern. CAREFULLY grind this down (or file it if you are patient) till it is close to the pattern. Make deliberate, but slow and even passes with the grinder for best results. Stop before you get into the wood and watch how you hold the grinder so the center cut is not deeper than the ends. Once you get close, get out the fine-flat-file and work it evenly and parallel with the wood. The block can move around at this point and it isn't a big deal, but try to keep from getting the wood till you are almost done. You will need the practice when you start doing the other side. Now for the hard part... After you are satisfied with the first flat, the other one needs to be cut! Don't panic, or move the wood block pattern yet. Take your scribe and good straight edge and make THREE lines across the center parallel with the first flat. Just in case you are off the three lines will help you guess. Trust me it is more accurate than you think. Extend the lines onto your wood pattern but not as aggressively so the line is thin. Flip 'er over and start grinding again! Same deal, stop a little early and take the time to file. When you are taking wood from the pattern and satisfied it is filed flat, with the marks still aligned, you need to start measuring. The pattern will get you close but you really need to get the calipers out for a good solid mating surface. They also let you know if you are out of parallel and generally a good tool to have. If needed, put the wood pattern back on and align the marks before filing. The pattern will keep you parallel and keep from ending up with a flat that isn't.... well.. flat! With this method, this shaft seen in the photos was within +/- 2 thousandths and parallel enough that I couldn't see light coming through the caliper jaws. Even my machinist friend was impressed. Here is the final result. I only needed an inch but the extra length helps when filing diagonally to make a really flat area. I even shoved it into a new U joint. I had to lube it up because the first time was a tight fit. No slop and I barely got it off with my hands. The End.
A cheap and effective way to make DD shaft, a little patience and you're gold. This is basically the same way I make mine. Nice job.
Almost forgot to add. Make sure that you follow manufacturer instructions of the joint you have, whether it be a set screw type, weld on, or through hole!
Nice post. Check out Austin's build thread. We should all have his patience and persistency. In an equipped shop, you'd be dangerous!
Thanks for the comments. I really appreciate the kind words. I figured now was the time to post something useful after all the good ideas I have picked up here!
Wow thanks for the compliments! I'm sure a lot of you guys have already done the things I'm learning, but hopefully the next young guy can put it in his 'toolbox'.
The most important part of Tech Week to me, is a least a few people will see something that starts them on a life of making things yourself, and then end up pushing your own limits. Good thread.
This method works very well--even for me. I just went very slowly and measured often. Thanks for a great tip!
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