building a 34 drive shaft

[cas3]

bad day at skips drive shaft shop. i loaded up all my parts and headed off to the pros, to have them weld and balance. my memory failed, and they do not have a chuck on each end of they're fancy pants machine, its a face plate with only the jigs to do modern drive shafts, grabbing on the u joint. they said they could do it, but would have to fabricate a way to hold a round shaft, at 3-4 hundred dollars, as opposed to a 50 dollar balance job. i went home and called every drive shaft place in the mpls-st paul metro, and it seems they all have the same machine, cant do it. so, i then called a few street rod shops, who told me to call all the folks i already called. i suppose all they're banjo rears are on the scrap pile. i then looked up industrial shaft repairs, and found a place that works on large pumps and fan shafts, and like 34 bill in post 32, they can spin it on trunions, wheels, but would weld it by hand. so, i put my new male end in the tube, zeroed it in the lathe, tacked it in 4 spots correcting it with each tack, and then welded it up. 14 thou run out at the front end of the bearing surface, held with a steady rest, and chucked at the rear, so i'm sure way more than that on the end spines where the u joint should be happily spinning true. not good, so i flipped it around and grabbed on the male end bearing surface with an aluminum sleeve so as not to wreck the surface. wow!!! 14 thou turns into about 250 thou 5 feet down the road. so using the pea spot heat method , cooling it with snow (sorry, i know you southern guys are jealous again) i got it closer and closer, but it took many times. i soon realized the aluminum was weak and would change my readings, even after i had a breaker bar on the 4 jaw chuck screws it seemed to move. at one point i was only 30 thou out, but the next times made it worse. i quit for today, i need a steel sleeve to grab on the shaft, or brass? way to much time in a simple thing. i have made "modern" drive shafts before, with only one failure i can remember, but never done the male splined end before. tomorrow's another day

 

[JSeery]

Thanks for the update! Sounds like loads of fun.

 

[cas3]

well, i got as close as i am gonna get, 15 thou out, but at 5 feet thats nothin. it took about 20 times of heating. and after about ten times of only gaining 5 or 10 thou( remember i started out needing about 250), i started to add some weight on the shaft to persuade it some, as in the photo. i hope all this heating and cooling has not wrecked my home made and already questionable male end. amazing what snow will do, even at room temperature you put a hand full of snow on the shaft and watch the dial move 50 thou. another interesting thing here, while i had the lathe set up already, i checked the other 3 drive shafts i have. with the rear centered in the 4 jaw, steady rest at the end of the tube, and indicator on the farthest front point, they were .025, .035, and .040 !!! crazy! i thought mine freshly welded at .014 was bad. these were all taken out by me, not laying around for decades. so, ford let them out like that?

 

[cas3]

nearly a month, and i am still fighting with drive shafts. headed out to the industrial shaft place, shermco, big outfit, they have shops in about 20 cities, on monday morning. i got about 25 miles from home and the timing belt went on my salt encrusted winter beater. (good cars hibernate in winter). when they say 60k miles, they mean it, this one had 65k on it. back on the road today, 130 mile round trip. shermco and i had a long discussion on the phone, even put the operator of the machine on a 3 way chat, we all knew what i had, what i had done, how straight it is and must stay, and yet they never asked how much it weighed. it turns out they do great big electric motor armatures, and the machine will not read out accurately at less than 25lbs. they say it will give a reading, and when you correct it, it will give another nonsense reading to correct again. we had the shaft on the machine, golly, it sure looked true when spinning, i was proud papa, but no balance. they told me about another shop that had the machine to do it, but last year the owner retired. they went on to say they tried to buy the machine, but the owner chose to keep it, saying he may do some small jobs yet. perfect! i thought who is the guy whats the number. they gave me the number--its dead. so, as i sit 65 miles from home i call my buddy who spends too much time on line, and googles and gives me the address, and also we google again at shaft repair. i get 3 places to call, first 2 say no, too light, 3rd place says, "if you are at shermco, and they cant do it, and cant tell you who can, then it cant be done". so, on the way home i drive to the address of the retired guy. northeast mpls used to be the polish part of town...but times have changed. i should have caught on when everyone i saw for the last 20 blocks was wearing a burka. when i got to the address, it was "the nigerian center for health and wellness". i sat there...pondering...would they know anything about the former owner? its a big building, maybe he has a spot in the back. so i went in, no they knew nothing, i did not mention balancing for fear they would have thought how much can they balance on they're head. so back home again. i have one last resort, my friend who has a static balance thing we use for model t shafts, and flywheels. my concerns with this is, the tube has a seam. if it show a heavy spot that is not on a seam, you might be doing something. if it stops on the seam you are done, and i am going to just put them in and see what happens. now, if i was to do this again, heres my thoughts. first, i have 5 shafts here, and no visible marks that ford ever balanced anything. i like to think its important, but did he get away without it? and how did they keep it straight when made new? remember all my other 3 shafts were about 30-40 thou out at the male end. i talked about this at shermco and they had no idea, weld makes heat, heat makes things move. how did they do it? now, if you have a perfect tube, like 4130 seamless, then many engine builders have a dynamic balancer for crank shafts, but not very long, so the tube must be perfect as they will run on the tube, not the machined ends like i was trying for. so, the way to do it is like ken showed us, using new tube, new rear, good front???where the heck do you get them? to recoup, i hired the pro welder to tig my ends, and he migged it. i went to two places that said they could tig and balance, and neither could do it. i try so hard, and then you hear about the guys laying it in a piece of angle iron to weld it and it goes just fine! so one more attempt in the static rig, then i am done, i need to proceed on. and how many drive shafts can you balance on your head? i had a hard time carrying two into the shop. rant is over, one more update tomorrow.

 

[rotorwrench]

I balance rotors as part of my profession in the helicopter service & repair business. The key thing about balance is how far the mass of the rotor or shaft extends from it's rotational center line. The larger the shaft gets in diameter, the more important the balance is. Runnout (turning off center) is also very important on a shaft. If it turns more than .004" off center then it can have a balance problem. If your shaft turns with no more than .001" runnout, you shouldn't have much of an imbalance even with seamed tube.

When static balancing on knife edges, find your seam and set it up on the balance knives with the seam facing either right or left then let go and see if it moves. Make sure your knives are as level both ways as you can get them. They have to be Very level. If it turns, then the seam will require compensation to prevent any rotation what so ever. If you get it there, that's about as good as you can get it. My old Chadwick Helmuth balance equipment could be rigged up to balance it dynamically as long as it can be turned at a known rpm but any masses turning with it have to be balanced as well so it would be a job to get it done and I don't think you will have to worry about it unless you feel an imbalance when you drive the vehicle. If you get it statically, that should be good enough.

 

[TerryOH]

Had to modify the pinion end of the shaft, when changing gear ratio. Had all the parts machined for a very tight fit and aligned on a long bed lathe to have both ends of the shaft very close about .005 then tacked the new pinion end to the shaft and rechecked alignment. Then welded using a crank shaft welder with first pass in the V-grove between the two pieces and then two additional overlapping passes. See photo below. I was not too worried about final balance since the shaft was seamed tube. and such a small diameter. I have not seen balance weights on any of the original shafts. I have about 1K miles and do not notice any vibration.

 

[40 Deluxe]

Looks like that Nigerian prince with all that money to give away has a Minnesota branch! Or maybe this is where the "mover" brings all the cars and parts they buy on Craigslist with those hot checks!!

 

[cas3]

Terry, did you bore the pinion end, or replace the whole part?. nice job with the crank welder, hadnt thought of that. well today i went to the static balance operation. funny the one with my home made front was right on! nothing done, spun to a different spot every time. the other however is bad. this was my best ford front, and i change the rear. it had a bad spot of corrosion on the tube, i didnt like it, but did not think it would create such a problem. we had two 3/8 nuts taped on the light side, no change. so then grind a bunch off the coupler at heavy side, no change. next start making it uglier, and uglier welding blobs on to replace the two nuts, and ended up with this gross looking thing. its close now, but the fact is i should buy a new 4130 tube and start over. there must be a lot of material missing from the rusty spot. score is one win, one loss

 

[TerryOH]

I replaced the pinion end of the shaft.

 

[JSeery]

Terry, did you bore the pinion end, or replace the whole part?. nice job with the crank welder, hadnt thought of that. well today i went to the static balance operation. funny the one with my home made front was right on! nothing done, spun to a different spot every time. the other however is bad. this was my best ford front, and i change the rear. it had a bad spot of corrosion on the tube, i didnt like it, but did not think it would create such a problem. we had two 3/8 nuts taped on the light side, no change. so then grind a bunch off the coupler at heavy side, no change. next start making it uglier, and uglier welding blobs on to replace the two nuts, and ended up with this gross looking thing. its close now, but the fact is i should buy a new 4130 tube and start over. there must be a lot of material missing from the rusty spot. score is one win, one loss

Looks like the tube itself could be a lot of your problem here.

 

[cas3]

yup, the tube is worse than i thought. even this ford front while it has a nice smooth finish, it does show a couple thou wear. any one have some 35 fronts they cut off to make megaphone pipes?