J I love the write up on the drive shaft! Very sound information and well written.

Years ago I started setting aside drive shafts as cores just to have on hand when I did various swaps (I’ve probably got 50-75 in the back shed). A lot of times I had something on hand that would fit with no mods, just the right combination of U Joints. Something I learned over the years was to use a paint pen to mark the end of the drive shaft with the U joint number so I didn’t have to go thru the measuring to figure out what joint I had used (especially if it was a conversion joint).


I used to have a local shop here that would shorten a shaft for under $100 and it was just easier to send a drive shaft in to him than building my own. Unfortunately like a lot of things the guy was older and retired several years ago. The guy he sold the shop to was pretty much incompetent and he went out of business in a year. So I was back to building my own shafts…..something I had done years before.

I do mine a little different than you do. I’m one of the guys who uses a big tubing/pipe cutter to shorten the shaft. You’re absolutely right that it “squeezes the tube and reverse-flares the cut end”. The trick I found is to go slow with the cuts which minimizes the squeezing and then using a die grinder to get rid of the flare. I prefer the cutter as it leaves a square 90 degree cut (provided the blades are tight and sharp. Then when the yoke is hammered in and the shoulder seats to the shaft you’re almost assured the shaft is straight (assuming you are using a straight donor shaft to begin with). I usually try to start with a shaft that has no balance weights if I can find one. All I can say is that I’ve been real lucky doing it this way.

If it doesn’t vibrate when I drive it I call it good, and fortunately (at this point anyway) there is now a good drive line shop in Tucson who can straighten and balance for me at a reasonable cost.

The one that I'll hopefully find out how well I did with is in the 37 Dodge. I figure with the 4.56 gears it should really be humming at 75 MPH. Any issues with it being straight and balanced should show up real quick




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