HELP HELP WITH A BROKE BUSH HOG

[Anonymous Poster]

I was at a tractor and equipment auction a couple of weeks ago and found a 6’ rotary cutter that first appeared to be in rough shape. Being in need of a larger cutter I was immediately drawn to the possibility of a “diamond in the rough” at a bargain price.

The tailwheel frame and assembly was extremely heavy built as was the front 3ph frame. As a matter of fact the whole thing was built like a tank but the top was completely rusted out – you could see the ground in several places. The only thing I could figure someone must have parked it in a cow lot or under a shade tree where cows congregated and their discharge caused the top frame to rust away.

Well, I looked under it as best I could, turned the driveshaft and checked the gearbox for excessive slack and smoothness. It felt smooth as silk! I could tell that the bottom seal was gone in the gearbox as there was several layers of oil and grease all over the blade carrier.

Well, cutting to the conclusion and question – I bought the “hog” for $130. When I got it home I hooked it up to my tractor and it operated like a champ. The gearbox was smooth and quiet and it cut like a dream. The top is so bad though I was afraid that the gearbox was going to fall through the top.

I called my local foundry for some ¼” plate, heavy angle and some flat metal to build a new top. It came to less than $200. HMMM - $130 plus $200 equals $330. for a 6’ cutter built like the titanic. Sure it would be a lot of work but I enjoy projects like this and I’ve got plenty of time before it’s bushoggin’ season. I even found a new one ($1350) that I planned to steal their design.

I planned to take the gearbox off first, followed by the tailwheel frame and finally by the 3ph frame, then basically scrap the rest. PROBLEM – After wiping the grease off the nut holding the blade carrier to the main shaft I discovered it had been WELDED to the shaft. I don’t mean just tacked either – it was welded all the way around.

I can’t find a name on the hog or the gearbox but I admit I haven’t cleaned the gearbox real well. Like everything else it is rusty and coated with crud but I am pretty sure it doesn’t have any kind of plate on it.

If I cut the nut off the shaft then naturally it (the shaft) is ruined. Does anybody know how many manufacturers of gearboxes there are. I remember someone saying one time that there were only 2 or 3 manufacturers of gearboxes and I remember that person saying that Borg-Warner made most of them. Does anyone know if this is true??? I am pretty sure Howse makes their own. It stands to reason that if they make theirs then the others probably make their own too.

I welcome your advice. Should I sell this thing for scrap or is it worth trying to fix the main gearbox shaft?? I though about trying to get one made at a machine shop but this is not a part that you would want to fail and the cost would probably be enormous.

 

[Anonymous Poster]

Post a few closeup pictures of the gearbox and cutter and I'll try to ID it for you...

Some of the more popular gearboxes are OMNI... {most rotary cutter manufacturers don't make the gearboxes...}

How do you expect to change the output shaft seal with the way it's welded...? {you can replace the output shaft but you'll approach a new cutter with the amount of dollars you could end up investing...}

But lets see some pictures first... /w3tcompact/icons/smile.gif

 

[bky]

is the metal good around the gear box? If so couldnt you cut the metal around the gear box and then weild it on to the new metal?

 

[jasonf]

I would think you would be able to grind off the weld with a angle grinder, or a Oxy Acetelyne torch. Any welding shop should be able to blow off the weld and a machine shop could remake the threads, seems like you will have to do this anyway to get at the shaft seal. Lets see some pictures like John said so we can see what is going on. You may be able to open the gearbox from the top and remove the pins/clips and be able to remove the shaft with the blade attached from the bottom making it easier to work on and transport. It may still be worth doing.......

 

[Steve_in_Ont]

It is possible to get most welded nuts off without destroying the threads. It takes:

1. Luck
2. A good hand with a torch, and
3. Did I say "Luck"?

I have a '52 M37 (military version of a Dodge Power Wagon), that some bozo had welded the steering wheel onto the shaft... Very carefully & with alot of heat, we where able to get the old steering wheel off and save most of the threads.

Good luck!

 

[JerryG]

Noname,
Like was said before I would try to remove the weld. You could use a grinder and go slow or get someone that is good with a plasma cutter to cut the weld out.

 

[rbargeron]

The question is "why is the nut welded?" Maybe the threads on the shaft or nut are stripped. Maybe the seal is leaking because the bearings are worn and allowing too much runout. Is there play in the main pivot?

On the better-quality gearboxes, the main pivot shaft has tapered splines and is hardened. It is possible the weld isn't that well adhered and might come away clean. Maybe the nut could be split with a die grinder and the shaft can be saved.

I re-shimmed an old Massey gearbox once to get the play out - it stopped leaking and ran fine for several years.

Good luck

 

[looch]

<A target="_blank" HREF=http://www.hubcityinc.com/>Hub City</A> in Aberdeen, SD made the gearbox on my tiller.

Also, the output shaft on my snow blower's gear box broke. I brought the two pieces to a local machine shop (my father in-law) and they made me another.

 

[TBone]

JM3 and all the other helpful folks,

First I apologize for the NoName post. I was on someone else's computer last night and when I tried to post under TBone I got a message that the name was already being used (Yeah, by ME). Anyway I didn't have time to figure out what to do and I was anxious to get some advice so I posted under NoName.

JMIII - I am not digitally blessed so it may be a while before I can post some photos but will try to do so if I can. As you noted I can't change the seal or anything else until the nut is removed and its removal will definitely ruin the shaft. If I were lucky enough to identify this gearbox as an OMNI for instance, where could I purchase the shaft and do you have any idea of the cost? P.S. The hog has a heavy duty clutch just like my neighbor's Rhino but the gearbox does not look like his.

bky - No I'm afraid there is not enough good metal around the gearbox to use either.

jasonf - That is an idea if the shaft is pinned to the gear. I might be able to unpin it and drop it out the bottom. I haven't pulled the top off the box to see if it is made that way. Some of them are built with the gear all in one piece I believe. If it does come out the bottom is this going to allow me to change the rear seal?

To all the other helpful folks - I'm afraid there just ain't no way to save this shaft. The nut is just one big glob of weld and the end of the shaft is completely burned away. I am fairly handy with a cutting torch and I am going to cut it as best I can but I think saving the shaft is hopeless.

As always I am impressed with the level of knowledge and ideas on this board. Thanks to all for the input.

TBone

 

[beenthere]

I thought the suggestions to grind the weld off and/or blow it off with a torch or plasma cutter would be options for you. You however don't seem to think they will work? Is it because of something you see that we don't?
Also, splitting the nut apparently won't work, as you see it, either?