The Stovebolt Site Forums The Shop Area Driveline PTO driveshaft machining

Gentlemen,

The rear section of the PTO driveline on my 42 dumptruck is missing. The shaft is a solid 13/16 inch rod with a woodruff key slot on one end and a approximately 5 inch slot on the other end to accommodate a slip joint. Both the woodruff key and slot are 1/4 wide. Having trouble finding the correct shaft as most modern applications use different diameter shafts. How difficult would it be to machine the slots, and is this something that a driveline shop can accomplish?

Thanks,

Paul

Woodruff key machining tools are readily available, not something driveshaft shops can handle, need a Bridgeport or other milling machine, plus knowledgeable operator. Are you sure the rod is not a common .750 size? Anyway, a crs shaft of the correct size can have both ends done be the same tool. Look for farm PTO people or truck people, might have to supply your own cutter if they don't have your size.

Grigg on here in VA might know someone, or he could do it.

Ed

I'd choose to use a larger diameter shaft, maybe 1" or larger, and turn the ends down in a lathe to fit the hardware. Another option would be to weld correct-diameter stub shafts into a piece of heavy-wall tubing like Schedule 80 steel pipe. You're going to need a machine shop to mill the key slots anyway, so the added machining time to turn a larger shaft down won't add a great deal to the cost. Small-diameter PTO shafts have a habit of twisting, getting the U joints out of phase, and setting up destructive vibrations and stresses on the couplings.
Jerry

13/16" seems an odd shaft size to me as well. are you sure that's the diameter?
If so are you trying to stick with that and be "original" or have you considered an entire new shaft and joints from say 1"?

I'd look locally for truck equipment dealers/installers, they may have all the parts you need in stock and might be cheaper on the keyway cutting cost than a job shop machine shop.

Have a look in this catalog, they do list 13/16" components.
http://www2.dana.com/pdf/U330.pdf

Grigg

Thanks for the replies, I was hoping the resident Stovebolt machinists would read my post. Jerry now that you mention it, the parts manual does show the rear shaft (the one I need) is a larger diameter and turned down at both of the yoke mating areas. I will see if the machine shop has a lathe that can accommodate a 51 inch rod. Do you think it is really necessary for a retired truck...this old girls hard working days are behind her? The shorter front shaft (31 inches) is not a larger diameter, 13/16 from one end to the other. Grigg, yes it is an oddball diameter of 13/16. Shafts on the PTO and ram oil pump are also 13/16. I found some 13/16 round stock available at Fastenal, and a machine shop that can cut keyways. Could either of you SWAG a shop time it should take to do this little project?

As long as they have a lathe with a center hole in the spindle big enough to accommodate the size shaft you choose, it's easy to support most of the shaft on V blocks and just stick a few inches out of the chuck, machine it, then reverse the shaft and do the same thing on the other end. 1" diameter round stock is easily accessible, and cheap.

Just for cutting the keyways, I'd guess about 2 hours' time, max. Maybe less if your machinist is quick at getting set up to make a cut. That's a pretty simple operation, and regular 1/4" key stock could be substituted for the Woodruff key, which would make setup time even shorter.
Jerry

I'd say have them cut for the woodruff key if you want to, it's not really any longer or shorter either way so long as they have the cutter for that width and diameter key.
The same cutter and setup in the mill will allow them to cut the longer keyways.
2 hr max, might come in under an hour if they're proficient at it and have the tools handy.

Find your local gear and bearing supply shop. They will likely have exactly what you need in stock. Including any U-joint parts.

I think I may have found a suitable shaft that already has a keyway cut along the entire shaft. Do you all think a 0.125 deep x 0.250 wide slot is suitable? The slot is the correct depth/width for the sliding yoke side, but it is cut shallower on the fixed end yoke side where the woodruff key would have been employed. The woodruff key is 0.375 high so the slot on the shaft would originally have been 0.250 deep on that end. Do you think a length of 0.250x0.250 key welded in the shaft will be suitable on that end?

Thanks for the Spicer/Dana link Grigg as it produced a viable (although obsolete) part number. The vendor was surprised to see interest in a part that has languished in a corner for decades. If it works, this alternative will be much less expensive than the other alternatives. I still have not purchased the shaft as the young guy on the phone wanted me to wait until the "old guy" at the parts desk came back to work as he "remembers when this old stuff was actually used".

Stovebolt rocks!, thanks for the great intel.

For such a long shaft I would not want a continuous keyway. Slightly weaker, more risk getting wrapped up in it too because not smooth.
It would be fully functional.
It'd look wrong to me.

Since the shaft is obsolete, and it's been on hand for years, they might be willing to make you a racehorse deal on it. The square key instead of the Woodruff key should work just fine- - - - -I ran a heavy-haul wrecker with a 35 ton belly winch for several years and used nothing but square keys on the PTO shafts. A few got loose and fell out, but I never sheared one off, even when making some extremely hard pulls.

Braze the key into the shaft, don't weld it. If you want to smooth up the groove between the yokes, fill it with J-B Weld. I really doubt that's going to be necessary, however.
Jerry

Jerry,

You think brazing would be preferable to MIG welding at each end of the keys? I was thinking that a quick MIG bead would not build up as much heat on the shaft.

Still waiting on pieces and parts. Had a yoke/key disagreement on one of the shafts and needed to hunt the correct end yokes so the shaft was in phase. Why on earth were there so many different configurations for yoke and set screw locations? At least now I can identify a 12 o'clock keyway and 9 o'clock set screw yoke at a glance...

Either way would work. When I'm cutting my own keyways I use a center-cutting round milling cutter, and make a plunge cut without extending the keyway all the way to the end of the shaft. Then I radius the ends of the key to match the shape of the slot, and the key retains itself. Obviously, with a shaft that's slotted all the way, that's not an option. Another trick is to use a setscrew with a cone point, and drill a dimple in the key for the point to fit into. That doesn't work on a sliding yoke, however.
Jerry

Hey all,

Following up on my PTO driveline question. After sourcing yokes from Michigan and Massachusetts, keyway stock from Georgia, and the elusive new in packaging Spicer 13/16 diameter keyed shaft from Loisaiana; I have finally gotten this portion of the project toegether. Oh, a couple of small parts like u-joints came from my local parts store here in North Carolina.




This is the first time this dump bed has functioned since the 70's. The PTO and pump actuator levers, and rods had to be fabricated as they were absent when I became the caretaker of this 1942 WW2 truck. After repacking the ram, pump, and actuator rods; the original Hercules cylinder/pump works quite well.

Enjoy!

Paul