making a drive shaft, need info

Thanks for the details Bob I appreciate all the help I can get

 

I think you want tubing not PIPE.

 

In MY driveline shop, over half of the home built driveshafts brought to us to be balanced have to be recut, straightened, rewelded, then balanced.
Even some local machine and welding shop stuff has to be treated the same way.
Just having a square cut on the end of the tubing doesn't make for all the answers of a straight and true shaft.
My tolerances? Straighten to with .003", better at dead nuts zero. Check the center of the tube, within .020". Then tack and weld. Has worked for me since 1989. THEN go to the balancer, look at the center of the tubing again while spinning at 800 rpms. Start balancing.
Yeah, I bet I could do a good garage job if I had to, do it scientifically. But I don't do it.

 

a buddy of mine used 2 1/2 inch dom 120 wall tubing for one.... if you dont have a long one to shorten then the dom is the way to go if you buil your own... i spent the 250 and had one made...

 

what's a good source to have one made? anyone besides driveshaft shop?

 

The only time I had a pro do a driveshaft it vibrated. Follow the directions here and you should have no problems. Just remember to leave the factory balance weights on.

 

My brother used to weld them up by rolling them slowly across a flat concrete floor while welding them. Then, we would use radiator clamps to balance them, through trial and error.... LOL.... Not really a recommended way to do it, but he sure seemed to get them to balance out and not vibrate. LOL.... I don't think I would do it any more.....

SpeedAddict001

 

I had an all new driveshaft built for my Divco at a local driveline shop for $250. I would like to do my own on the next project (cruiser not a racer). I didn't see anyone mentioned what kind of weld. MIG, TIG or Arc?

 

Mig is probably most common, tig is overkill but would work great, arc works just fine.

 

I've done a lot of home made drive shafts by simply scribing a line down the length. Cut near an end. Chamfer the edges and clean to bare metal back about 1 inch inside and out. Line the 2 pieces up on a straight length of 3x3 angle and clamp them with a 1/16 gap. I use Tig and tack 4 places. I do a root pass even on the thin stuff. Lightly vee grind smooth check for cracks and do a final weld pass. No undercuts permitted. The process is exactly the same as some weld tests I've qualified on.

The last one I made, I made just because someone said it couldn't be done at home. Put it on the Willys and laid all 500 hp to it. It's still there. I had to take it out as the race tech guys needed a pro made one. Haha. Big deal I went and got one made at Clutch and U-joint for $250. Nice piece. Looks just like my home made one except I have better looking welds. haha

 

There was a thread on here a few weeks ago on home built driveshafts - do a search!
Before you do your tack welds, install a new U-joint and install the shaft in the car. Trans in neutral, dial indicator on the end nearest the proposed weld, rotate shaft to find run-out and correct as necessary - then tack weld. Check again for run-out. If OK, remove shaft and do final welding. When done this way, your shaft has been centered on the actual bearings that it is going to run on! And the chances of vibration are miniscule.
My experience with assembly-line driveshafts (factory) is that they were welded off center (but within factory tolerance [intolerance?]) and therefore required a big blob of weight to correct the imbalance. Most red blooded hot rodders want to improve on the factory assembly-line quality. Don't we?
I am convinced that with your skills developed in the pipefitting trade this project for you will be a cakewalk. There is enough info here to do it yourself correctly.

 

Here is a pictorial on how to shorten your driveshaft. You may need to shorten your driveshaft because of a tranny change, rear end change or in my case, because I had no driveshaft at all for the '65 Mustang I am working on. This may be one of those projects people shy away from because they think that there are special procedures, tools or black magic involved. I am here to tell you that I have shortened dozens of driveshafts this very way, and very very few have needed to be balanced.

The car I am working on had no driveshaft at all, so I went to the driveshaft vault and found a suitable core. In this case it was a Ford driveshaft out of an un-known vehicle, but it was a 3" O.D. shaft that had 3 1/4 yokes that would accept 1 1/16" U-joint cups, which is what I would be using. I inspected it for dents and rust or any other damage and deemed it suitable for shortening.

The first step is to measure for the new driveshaft. The procedure I use is to push the slip yoke all the way into the tranny, and pull it out 1 1/4":



With the weight of the vehicle on the springs, I measure from the flat of the rear end yoke:



.......to the center of the front U-joint. In this case the measurement was 51 1/2":



We now need to cut one of the yokes off. I try to cut opposite of the balance weights if I can. I grab my 4 1/2" angle grinder with a thin cut off wheel and cut the edge of the weld towards the center of the shaft. You need to cut only as deep as the tubing is thick so in our case, slightly more that 1/16". It is better to cut a smaller amount than needed than to go too deep:




With the cutting done, the yoke should come right out with a couple of taps of the hammer. If it does not come out, you need to cut a little deeper:



This is the yoke after is is out of the shaft:



We now need to shorten the tube. The shaft I was cutting was 56 " center to center, so 4 1/2" would need to be cut off. I use a thin wall tubing cutter because it cuts perfectly straight. You could use a cut off saw, but make sure that the cut is perfectly square:



Here is the tube after the cut and after de-burring with a file:



The yoke can now be tapped in to the tube and the center to center measurement adjusted. I like to leave about 3 /32" of a gap for welding into. I also place both flats of the end yoke on a flat surface to make sure that they are both in the same plane. You can adjust the yoke wherever you want it with a couple of hammer taps:



The front U-joint and yoke can now be installed, as well as the back U-joint. The driveshaft can now be bolted into the vehicle. At this point you might be thinking,"He forgot to weld the yoke on." I didn't forget, I do this so I can check the run out with a dial indicator. I mount a dial indicator on the rear end, and set it against the drive shaft tube to measure the run out. You can now adjust the run out with a few well placed hammer taps. I try to achieve the smallest amount of run out possible, in this case about .004" which is pretty good. With the driveshaft still bolted in the car, I tack weld it in four places:




The driveshaft can now be removed from the car in order to be welded. I would strongly suggest that you have at least a 185 amp MIG welder for the next step. If you are not comfortable with your welding skills, take it to someone who is qualified to weld it:





A little paint, and we now have a finished driveshaft. As I said before, I have shortened dozens of driveshafts just like I describe, and only a few have needed to be balanced, but even if you need one to be balanced, you have saved a considerable amount of money shortening it yourself:

 

Senior member "Drive Em" ...... excellent "how to shorten a driveshaft" seminar.

 

One of the machine shops in town balances shafts for $50 cash... you could probably find the same deal. Try one yourself, if it shakes, balance it, if it still shakes, figure out why and try again. You'll get it right. By the time you're done, you will also have the knowledge and confidence to go at it again one day. Great investment!

 

I have shortened several myself and I always put the shortened end at the rear end. Reason being if you dont do a good enough job of welding it or if it vibrates so bad it comes apart, you would much rather have the rear one fail than the front one. I have never had one fail but still do it anyway. I have a lathe I use to cut the tube and line it back up with a dial indicator then wire weld it.

 

Nice Job!!

 

Pipe is for POOP, you want tubing!!!