Another Build Thread - My '32

[timothale]

I always try to find a drive shaft that doesn't have any weights, or very small, better chance of not having a balance problem

[J. Robinson]

Now don't go lopping the rear yoke off with a chop saw or you'll ruin the whole thing. What we have to do here is grind the factory weld down so it's smooth and then cut through the outer tube only so we can knock the yoke out of the tube. After grinding the weld, I use a piece of thin aluminum wrapped around the shaft so I can mark a straight line around it. Poster board would also work just as well. After marking, the tube can be cut with a hacksaw, panel saw or whatever you have. I use a thin cut-off blade on my grinder to cut around the line about 3/32 inch deep. A firm rap with a hammer on one side of the yoke and it pops right off. Now you can see why I didn't want to just chop off the end.

[NTFDAY]

How do you keep the end caps on the u joint from falling off? Seems as though if I breathe on one it falls off.

[J. Robinson]

Measure from the open end of the tube the amount to be cut off (in this case 11 5/8 inches). I used my chop saw now to cut the shaft, but it could be marked and cut with a hacksaw, panel saw, grinder, or whatever. I don't recommend using a tube cutter because it squeezes the tube and reverse-flares the cut end making re-installing the yoke a real challenge.

If you are using one of the special adapter U-joints, now is the time to install it in the yoke. Regardless, if you haven't done so already, wrap the U-joint with a few rounds of masking tape or electrical tape to hold the bearing cups in place... because we're about to get violent! Seriously, on some drive shafts (this one included) the yoke is an extremely tight fit in the tubing. On these Camaro/Firebird shafts the yoke actually creates a slight flare in the end of the tubing, as we will see.

The yoke will not go in the tube with a gentle tap; it will start enough to hold just a bit, but it will not go in far enough, so... after getting it started with the yoke aligned on the scuff mark I made earlier, I pick up the shaft and slam it vertically against the concrete floor to seat the yoke. This usually take 3 or 4 good hard slams, but it will go eventually. Once it's in there, put ONE tack weld on it someplace, preferably where it's not seated tightly against the shoulder. This will allow it to move a little for adjustment.

[J. Robinson]

Finally! Now I put the drive shaft in the chassis and bolt the rear U-joint into the rear end yoke. I clamped a piece of 1/16 x 1" aluminum strap to the truck arm to use as an indicator. (You could use about anything, wooden slat, heavy wire, etc.) If you have one, you could use a dial indicator, but it isn't necessary.

With the transmission in neutral and one rear wheel off the floor (both wheels if you have a posi rear), I rotate the wheel slowly while watching the shaft. If it's out of alignment (it was... slightly) it will show by touching the indicator on one side, leaving a scratch, and having clearance on the opposite side. Turn the "high" side to the top and rap it with a hammer (Not too hard! It moves fairly easily.). Try to hit it where the yoke and tube come together; hitting just on the tube will dent it and ruin the shaft. Keep turning the wheel/shaft and tapping with the hammer until it's perfect. Take your time - this is the most critical part of the entire process. You may need to move the indicator a few times to get a new scratch line. When you have it as near perfect as possible, put a tack weld opposite that first one. Now check it again. If anything moved, adjust it again with the indicator and hammer. If/when it's perfect put a third tack weld somewhere between the first two and check again. It should be good to go by now, but if anything moved fix it. If you have 4 tack-welds on it and it's still straight and true, weld it solid all the way around.

The last step is replacing the balance weight we removed earlier. After reshaping it a bit with a hammer and vise, I aligned it with the scuff line I made earlier and put 3 small tack-welds on it. We can call this one done.

[J. Robinson]

NTFDAY - Ken, I was busy typing the next post when you asked, but I think I answered your question there. If I have trouble with the cups falling off I wrap them with tape.

[NTFDAY]

NTFDAY - Ken, I was busy typing the next post when you asked, but I think I answered your question there. If I have trouble with the cups falling off I wrap them with tape.

Thank you for the reply, why I hadn't thought of that is beyond me.

[53 Chevy5]

I brought my drive shaft to local machine shop to get shorted. I marked where the weights went, but then I lost the weights. As long as I stay 65 or under it runs smooth. It's on the winter list to fix.

[40FordDeluxe]

nice work there and nice write up! The first one I cut way back when I stuck the drive shaft in the chop saw and figured out why you don't do that real quick.

[J. Robinson]

Believe me, Ryan, I have done things like that before, too. I was lucky with drive shafts, though. Years ago I saw a picture in a magazine of a drive shaft being made and there was a picture of the end yoke. All I had to do then was figure out how to get it apart. I had no idea about the balance weights and getting the U-joints in phase. Probably more luck than knowledge back then. I cut that first one with a hacksaw, welded it with a stick welder and it worked fine. The rest, as they say, is history.

[Mike P]

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




.



.

[40FordDeluxe]

Luckily I have a really good competent drive line shop that I take mine to. The last one I had shortened was $90. I can't mess with it for that and then I know I have it balanced too. I have shortened a few drive shafts but then took them to have finished. These tricks sure help though.

[J. Robinson]

Thanks. I wrote this for those who want or need to do their own. Where I live, for instance, it can take several days to get a shaft made or shortened. There is only one automotive machine shop in town and they stay pretty busy. Get in line and wait... and I hate waiting. If I'm not stopping to take pictures every step of the way I can knock one out in about an hour. In the time it takes me to drive down there, explain what I want, and get the work order, I already have it done.

[figure8]

thanks for the good tech

[53 Chevy5]

Some times I take all the shops around me for granted. I live by Rock Valley Ia, and I've been told by more than one source, more steel gets shipped in to RV than the whole state of South Dakota. Not sure if it's true but it could easy be. Lot's of machine shops, production shops, and black smiths around our area. You still have to wait in line though.