Have You Shortened A Driveshaft?

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bob w

Still crazy after all these years!
Joined
Jan 2, 2008
Messages
13,153
Location
Stillwater, MN
Usually I take driveshafts to a specialist. But, I have 2 to do. One for Zacho's truck and one for "Big Dodge". Prices around here have gone up a lot and my cash reserve is reading close to "Empty".

Have any of you shortened a driveshaft at home without benefit of a lathe? Some hints would be appreciated.
 
I have not done it but I believe that a guy over at the Club Hot Rod forum did. I think it's in one of his build threads. His user name there is J. Robinson. I'll look at up and post the link if you can't find it.
 
I have done a bunch of them, it is way easy. It is a little hard to explain.
I had an old time welder guy show me this trick 30 years ago, and it has worked well for me. You could grind off the old weld and clean that shouldered end up enough to get it to fit back on your square re-cut drive shaft.
Or cut the section out of the middle that you don't need, and split that waste section lengthways, hopefully you are cutting out at least 6-8 inches, longer is better. I use a plasma to split the waste piece, and I usually cut it on it's seam. You may need to cut out 1/8 to 3/16ths. Now the tricky part. Squeeze the waste piece down until it fits inside the old drive shaft. Tight. Put half of it in one end, and half in the other. Match the seam in the good piece to the split in the waste piece. Time the shaft, and weld it up. I usually seperate the two ends about 3/16ths and weld deep, to all three pieces. If this does not make sense, ask me questions. I started doing these for off road applications, but they snuck into street trucks with no ill effects thus far.

Disclamer: The previous statement was made by a professional driver on a closed course, your mileage may vary, not available in Alaska or California. For a complete list of all rules, watch your mailbox.
 
Thanks Gastrick. I tried Club Hot Rod. Even signed up. But, I couldn't find anything on driveshaft shortening. I searched J. Robinson and found posts but not on this subject. I'll keep exploring.
Bonehead, I've not heard of your technique. But since it works for you it will work for me. I'm excited to try it. I'm sure I understand your description of what to do. The removed section is split to resemble a big, long roll pin and then pilots the two halves.
BTW, I got my SLEEPERS t-shirt today and I reall like it. Thanks very much for the artwork and setting up the Cafepress arrangement.
Bob
 
Yes, you have it. When I said middle, I really don't mean dead center. I usually figure how long the waste length is and cut the shaft half that distance from the end. That way you slide that end in first, and it stops when it hits the end.

Glad you got and liked your shirt.
 
I’ve always taken mine to a driveline shop.
If you shorten it yourself, don’t you still have to take it somewhere to be balanced?
 
If you take your time, it should turn out okay. You could take it and get it balanced, but if it is wrong you should know it as soon as you go down the road. The most important thing is timing it when you weld it back, meaning lining up the flats of the U joints at each end. I do this on my steel welding table.
 
Okay, I read it. I have done it that way also, but I guess I am lost on re- attaching the weight. If the weight is there to balance the shaft why would it go back in the same place once the shaft was rebuilt?
 
Mark IT

I have done several shafts. Before cutting mark the shaft so you can put it back in same alignment. Each piece should be maked with lines that are easily seen. I cut it about 6 to 8 inches in front of back ujoint. Insert tube as Bonehead said and weld back together. Leave a small gap for the weld to penetrate. Grind weld same roundness all the way around shaft. It works for me and I'l do it again.
 
Regarding balancing, the shop that did the last 8 or 9 driveshafts for me doesn't balance them. On my Anglia I had a vibration that drove me crazy for a year. I took the unbalanced driveshaft (done by the shop mentioned above) to a different shop to have balanced. They said it was within specs the way it was. So, I had all those unbalanded shafts with no problems.
 
Gastrick, Thanks for looking up that thread on Club Hot Rod. I read the driveshaft shortening part. That is the technique I was planning on using, I just was reluctant because I didn't know if I could get a good result. Now, I have choices, which is bad for me. I'll fret about this for a few days and then do it one way or the other. It's only metal, right? I'm going to read the whole thread on the T build up. He's quite a home builder. Lot's to learn there.
Thanks,
Bob

Thanks to everyone that has contributed to answering my question. Truely, the RRR site rules!
 
An easy way to squeeze the waste piece is to use a pair of screw type hose clamps. This also works well when I want to fab a tapered collector for a set of lakes headers.

Ron
 
I've done a few for off road like roundy round racers. First mark a line on one side, then I just cut as close to the weld of the rear yoke as I can with a hacksaw, clean up the weld on the yoke with a grinder. After you measure several times and have determined the length of the tube, mark it. I have a pipe wrap but you can use a sheet of heavy paper and wrap it real straight around, tape it if you want. Use the paper edge to mark your cut. Take your time and get the cut straight. Check the cut in several directions with a square and do any touch up needed with the grinder. Now line the centerline/indexing mark up and put it together. Tap the yoke in as far as you can and make sure it is straight. Make a small tack weld, recheck for straightness, make another 180 degrees, recheck, another at 90 degrees, recheck, go another 180 from there and start welding it up.
 

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