782D CV driveshaft

[Jeff in Pa]

I made a set of adapters so a forum member could convert his 782 diesel over to a CV driveshaft.

Since this was first for me, I sent the adapters to him and he measured a distance of 15-3/8" between the adapters. He purchased a complete 1440 CV driveshaft assembly from a guy and had it sent directly to me.

The 1440 driveshaft assembly had an assembled length of 21.375 ( 21-3/8" ) After removing the CV joints off each end ( one slips off, the other is held in place with a snap ring ), the overall length measured 21.308

After a quick phone call to Sam Mac ( nice talking with you again ) , it was decided that an 1/8 of slip/movement would be used.

I chucked up the driveshaft in the Monarch CK12 lathe and cut off one end at what would be the middle. Then I cut off the other end one inch "too long".

The correct length section was drilled and reamed .3745. The inch too long section was turned to .3755 for one inch and then pressed into place with my arbor press. Both pieces also had an 1/8" weld chamfer cut into them.

After verifying straightness in the lathe, I tig welded the driveshaft back together. After cooling, I skimmed the weld to the .750 driveshaft diameter.

I was going for a 15.250 overall length and I ended up with 15.245

Jeff

[darkminion_17]

Very nice Jeff, just like you did for me, I wonder what hydro fan he is going to use?

[Alvy]

That's nice Jeff. Great work as always. Have a couple questions as there's a guy by me that makes custom drive shafts and for some reason I've never asked him but have watched some of his methods.

How do you control run out when it's done? I'm assuming the ends of the lathe and supposed to be perfectly straight so the shafts lining back up with each other isn't a problem because of both being chucked?

I would think that, but I'm not sure, do you use the lathe at a super slow rpm at the end to do a continuous weld around it with a mig or did you tig the final pass and do it a different way not using the lathe to spin it?

[Jeff in Pa]

Originally Posted by darkminion_17

Very nice Jeff, just like you did for me, I wonder what hydro fan he is going to use?

The one that came with the driveshaft. He's getting one of the fan supports from me too.

I used the same process on your driveshaft.

[Jeff in Pa]

Originally Posted by Alvy

That's nice Jeff. Great work as always. Have a couple questions as there's a guy by me that makes custom drive shafts and for some reason I've never asked him but have watched some of his methods.

How do you control run out when it's done? I'm assuming the ends of the lathe and supposed to be perfectly straight so the shafts lining back up with each other isn't a problem because of both being chucked?

I would think that, but I'm not sure, do you use the lathe at a super slow rpm at the end to do a continuous weld around it with a mig or did you tig the final pass and do it a different way not using the lathe to spin it?

I don't weld in my lathe as I don't want to take a chance on arcing on the bearings.

I make sure the parts are running as close to perfect as possible before machining and the check the pressed together assembly. A couple short TIG welds before I go completely around so it doesn't pull.

[Sam Mac]

He should be able to use a Cyclops fan

[Oak]

Nice work as always Jeff. I have a 782d in the on deck circle so I may be having you do one of those for me.

[Jeff in Pa]

Originally Posted by Oak

Nice work as always Jeff. I have a 782d in the on deck circle so I may be having you do one of those for me.

We'll do a two part like this one to make sure your engine is 15-3/8" between the adapters too.

Thanks
Jeff

[DieselDoctor]

Another well engineered project, Jeff. You do fantastic work!

I did the same upgrade to my 782DT (turbo) although I did a slightly different joint. I turned down the outside diameter of the two shortened pieces of driveshaft by a few thousandths to true the external diameter and made a 4" long by 1/8" wall sleeve to go over the joint. I assembled everything in the tractor and tack welded it. This way, I was sure to have the length dimension correct, and short enough to allow easy shaft removal. I then removed the shaft, checked run out in the lathe and did the final weld.

As Sam, mentioned the Cyclops driveshaft mounted fan for the hyd pump will work on the 782D and is what I used along with one of Jeff's fan reinforcement plates.

[Jeff in Pa]

I have the tools and the experience to do it for a "factory" look. Your way works well too.


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Regardless of which way is used, checking runout before and after welding is important.