Sickle mower blues

[TraderMark]

Last summer I bought a used JD 350 sickle mower for mowing around the pond banks.

I got it home, made some adjustments and did a lot of head scratching on how to hook it up correctly to my 1720 Ford.

It did a fantastic job mowing the 3 times I mowed last year, although I thought the wobble box was a little noisier than it should have been.

So I greased it up good every time I mowed, thinking that the PO probably didn't grease it often enough.

I thought I'd probably rebuild the wobble box some time this summer.

I got it out last weekend and made a trip around the pond, just grinning as all the weeds and things fell like crazy and left the pond almost picture perfect. But on the way back to the shelter, I decided to mow along the lane as well. Nothing but Bermuda grass there so what the heck, after all, this thing was MADE to cut Bermuda grass.

I went about 10 feet. The wobble box got a little louder, so I slammed my foot down on the clutch and looked back, only to see the pulley that USED to be attached the main shaft of the wobble box rolling down the lane.

I thought, "Oh GREAT. The nut's come off that pulley. Maybe that's where the noise was coming from, but I don't remember it being loose at all."

I should be so lucky.

The shaft itself broke! :mur:

I picked up the pulley, turned it over and there's the nut, tight as ever on the end of the shaft sticking out of the pulley. The other side showed a nasty break in the tapered portion of that shaft.

The shaft is EXPENSIVE!!!!!! More than I paid for the whole mower.

SO ..... does anyone know where I might find a used wobble box for a JD 350 sickle mower????


Mark

 

[Gordon Gould]

I don't know what the shaft looks like so this might sound dumb to you but here goes. If you take the shaft to a machine shop or a friend that can do machining you might be able to get one made alot cheaper if it is not to complicated. I had a shaft break on my trail mower and that is what I did.

 

[TraderMark]

Thanks Gordon.

That was my first thought as well.
But it turns out that the pulley fits on the shaft via a tapered fit. Machine shops around here are few and far between and to find one with a lathe that will turn a taper would require a trip of at least 100 miles.

Mark

 

[jbooth]

Thanks Gordon.

That was my first thought as well.
But it turns out that the pulley fits on the shaft via a tapered fit. Machine shops around here are few and far between and to find one with a lathe that will turn a taper would require a trip of at least 100 miles.

Mark

That taper should be very short and would probably be easier to cut by feeding with the compound rather than using a taper attachment.

 

[TraderMark]

Ya gotta love Craigslist! :laughing:

I found a sickle mower in my price range, within a distance I was willing to drive.
The seller left no contact info on Craigslist other than the email link assigned by Craigslist.
So I emailed, asking for more information, i.e. model number, make etc.

He must have gotten some overwhelming responses.
The same ad this morning has the price increased 150% ($300 up to $450 obo):mur:
but now lists a phone number to call.

 

[trueblue1963]

I've rebuilt lots of these mowers.You might want to tear it completely down, it may have other parts that are broke. If so your talking big bucks!!!!!!!!

 

[zzvyb6]

If its any help, the same part number shaft is used in 450 and 3700 model mowers (H62210). What are the chances of having it welded back together?

If you have any junk New Holland mowers around, they also use a wobble drive to crank the sickle bar. Maybe you could adapt a NH box and be a hero in JD Mower World.

My only question would be what made it break? A sickle drive actually uses very little power so there is not much torque on this shaft. If it was a bending load, how did that happen?

 

[TraderMark]

trueblue:
That's my biggest fear too. What ELSE is broke. I'll find the answer to that question this weekend I hope.
Rough estimate from JD for the parts for a MAJOR overhaul of the wobble box was ~$2200.00


zzvyb6:
I've been wondering the same thing. I don't see how there could have been any bending load on the shaft where it broke. The only thing on that end of the shaft is the pulley. Granted it's a heavy pulley, sorta like a small flywheel to help with momentum, I assume. The break doesn't really look like a shearing break to me either. But, I'll know more this weekend. I'm gonna tear down the box and see what the chances of repairing that shaft are and what else I may need. I'm pretty resourceful when it comes to sourcing parts so maybe I can rebuild this box for just a little more than I'd have in another used mower??



Mark