looking for a sprocket for my front PTO

[barts]

I'm looking for a 12T x 40 pitch splined sprocket (18 mm, 22 splines) Kubota part number 70050-01100. Messicks and my local Kubota dealer tell me this is not available, but lot of folks list it. It's basically a sprocket for a chain coupling, broached w/ the special spline to fit the front of the engine crankshaft.

I want to connect a front-mounted hydraulic pump so I can run the loader on my little B5100.

I can bore some 1.5" round to go over the spline and tighten down several 5/16" pointed set screws into the splined shaft, but that seems so... brute force. I'm not up for single pointing the spline w/ a slotting head in the Bridgeport. Any ideas where I might be able to locate the original sprocket?

Thank you for any leads!

- Bart

 

[coachgeo]

If the front PTO has splines on it like a typical rear pto see if you can get a spline adapter or anything else that has a matching female spline on one portion of it and then have a machine shop cut the female portion that fits the shaft and cut up a generic sprocket that match your parameters in order to mate/weld the two together.

Before that though of course check with McMaster Car to see if they have a sprocket with splines that match the shaft.

 

[BadDog]

I think what he's talking about is more like a timing or primary chain that functions somewhat like a lovejoy joint for drive misalignment. Basically a double row chain sized to match the sprocket, one roller per tooth valley. The drive shaft sprocket fits in one row, the driven sprocket is captured in the second row. Something like these...

 

[barts]

If the front PTO has splines on it like a typical rear pto see if you can get a spline adapter or anything else that has a matching female spline on one portion of it and then have a machine shop cut the female portion that fits the shaft and cut up a generic sprocket that match your parameters in order to mate/weld the two together.

Before that though of course check with McMaster Car to see if they have a sprocket with splines that match the shaft.

Thanks for the response. I've not found anything w/ a suitable spline; there's quite a history of people looking for such because the PTO adaptors wore out quite quickly as they were apparently too soft and the oscillating torque of the little diesels hammered out the splines after a while.

- Bart

 

[Diydave]

Coupla thoughts: Try searching for a splined connector at surpluscenter.com.

There's also a used compact tractor dealer, in Shippensburg, Pa, Weaver's, I think the name is.

Since a lot of Kubota engines have been used in other makes of equipment, you might find one on a paver, excavator, golf course equipment or other industrial equipment dealer's lot, or on the shelf...

 

[ShaunBlake]

barts, have you considered getting a sprocket with the correct teeth and having a local machine shop (or trade school) bore it if necessary, and broach it?

 

[OldeEnglish]

I agree with Shaun, a good machine shop will fix ya right up. It might be better off to have them mill the sprocket end of the saft down to a keyed bore that can easily be found.

This thread may be of some help to you.

http://www.orangetractortalks.com/forums/showthread.php?t=17284&highlight=B7100+hydraulics

 

[barts]

I agree with Shaun, a good machine shop will fix ya right up. It might be better off to have them mill the sprocket end of the saft down to a keyed bore that can easily be found.

This thread may be of some help to you.

http://www.orangetractortalks.com/forums/showthread.php?t=17284&highlight=B7100+hydraulics

Yup; that thread was inspirational .

The 'end of the shaft' is the engine crankshaft; that's staying in the tractor for now w/ any luck. I've got a good lathe and mill, rotary table, etc, but forming a spline of unknown pattern is a nontrivial project for me.

I'll look for a better kludge... prob. take this to the Fab forum.

Thanks for the help, folks!

 

[ShaunBlake]

...
This thread may be of some help to you.

http://www.orangetractortalks.com/forums/showthread.php?t=17284&highlight=B7100+hydraulics

Sure helped me! I hadn't seen that one, and I've been snarling at the hoses keeping the hood from opening since the third day I got the sweet thing.

 

[BadDog]

Sounds like you should be able to manage the splines with either the lathe or the mill. Maybe easiest on the mill with the rotary table to handle spline indexing, or rig the lathe spindle for indexing the required number of steps. You basically make a cutter by reverse engineering the profile from your stub. Then start with the first spline by locking spindle (holding hub on the lathe, or cutter on the mill) and traverse the cutter through the opening (saddle for lathe, quill or knee for mill depending). In feed per pass is generally going to be only a few thousandths. Keep going till you get to depth, then index to next spline. It's slow and tedious, but can be done.

The problem is hardness. This shaper/slotter technique only works with relatively soft hub material and ground HSS bits. You can do harder hubs with carbide, but now shaping the profile into the bit becomes more problematic. If you make something like this in soft material, lifespan may be an problem. So then you have to figure out either going with tool steel and harden/anneal, or case harden (nice hard surface for wear but remains tough); either in your shop or send it out.

 

[OldeEnglish]

Well that's quite handy to have some machining tools on hand! I'm still searching, but I remember seeing a post where someone made their own shaft with a larger female hub and a pipe flange. They welded the hub and shaft together, to the pipe flange, and bolted it to the crank. I did come across one post that someone used a love joy clamped on the splined shaft.... I'll see what I can find and link it.

What I have for my k48 mowing deck is an adapter that slips that 18mm spline and makes it a 30 mm spline (I think 30 but not positive). I'll post a pic of that later on, I have a spare.

That piece is part # 66704-88530
I found that pipe flange fix but its on tractorbynet.
http://www.tractorbynet.com/forums/hydraulics/244417-b6000-kubota-front-pto-2.html
A 3/4" weld pipe flange would. Making the holes workable would be the hardest part I believe. You may be able to find a blank flange, or make your own.

Maybe that will spark a few ideas

 

[MagKarl]

I wonder if you could marry up a spline socket with a sprocket. Turn to fit and weld together. Anyone use a spline socket to turn their crank? I was wishing I had one for mine a few weeks ago when I adjusted the valves.

 

[barts]

I've been giving this some thought, and I think I'm going to try some 5/8" hydraulic hose with sturdy clamps as a coupler between the two shafts, which will abut each other. This hydraulic pump doesn't take a lot of power, and this should work fine. The clamps, etc. will all be well out of the way, so no danger of getting something hung up on a spinning shaft.

I was considering the set screw approach I mentioned earlier, but the shaft still has the factory paint (365 hours on the meter - not bad for a B5100 that's 30 or more years old, so something less brutal seems appropriate.

- Bart

 

[North Idaho Wolfman]

I've been giving this some thought, and I think I'm going to try some 5/8" hydraulic hose with sturdy clamps as a coupler between the two shafts, which will abut each other. This hydraulic pump doesn't take a lot of power, and this should work fine. The clamps, etc. will all be well out of the way, so no danger of getting something hung up on a spinning shaft.

I was considering the set screw approach I mentioned earlier, but the shaft still has the factory paint (365 hours on the meter - not bad for a B5100 that's 30 or more years old, so something less brutal seems appropriate.

- Bart

Think again!
The damage that that will do when (not if) it comes off could cost you some serious $$$, radiators are not cheap.
The force that the coupling is under is very extreme, and it's not because of the pump it's because of the way the motor fires.