Slasher swing back blades binding up

[Parakleta]

I've just taken delivery of a new MF GC2400 with a 4in1 FEL and 4' slasher and I'm having some trouble with the slasher.

I was trying to adjust the slip clutch on the slasher but every time I engage the PTO one blade swings back and jams folded up. The vibration at this point is fairly severe and I shut down the tractor. I have to use a 3lb hammer to free the blade. I am engaging the PTO at minimum engine throttle.

The blade assembly is two parallel plates with two blades bolted between them, one at each end, and the top plate has the vertical shaft through it and welded. It appears the blade is riding up the weld and wedging between it and the lower plate. The lower plate is now bent and the weld is damaged. Both blades have done this.

I don't know if there is something misadjusted, or if I am doing something wrong, or if this is just an issue of faulty manufacturing or poor design. Anyone have any suggestions?

 

[Gordon Gould]

or if this is just an issue of faulty manufacturing or poor design. ?

It could be that one or both are against you. Is it assembled correctly?

The blades should swing free and never jam up.

 

[Parakleta]

Is it assembled correctly?

I don't know. It is now how it came from the dealer. I cut about 350 lineal metres when it was first delivered last night, and then went out today after I'd read all the manuals to check everything over and setup the clutch when the problem started. The manual for the slasher only says how to check the oil and adjust the clutch, nothing else.

The blades swing freely when I've unjammed them, the issue seems to be that when the shaft starts turning and the blades are stationary momentum is going to make them swing all the way back and they hit the bottom of the vertical shaft with some force.

Is anything supposed to limit the swing back at engagement?

 

[Gordon Gould]

I have never seen one where the blades couldn't swing all the way around 360* . Seems strange to me they should hit like that but I am not familiar with that design. Sorry I can't be more help. Does it happen even when you engage it at slow speed and then increase speed slowly like you should ?

 

[greg_g]

every time I engage the PTO one blade swings back and jams folded up. The vibration at this point is fairly severe and I shut down the tractor.

The folding back part is normal, the vibration starting up is normal. The blades normally straighten out from the centrifugal force, and - once both are equally extended - the vibration stops (typically within 5-6 seconds). What's not normal is that it remains jammed. I believe that's related to the fact that the stump jumper is damaged. But what caused it in the first place is going to have to be between you and the dealer.

I'd first try to see if the dealer would fix it under warranty. If they refuse, take off the stump jumper and try to repair the damage. Hopefully that will stop binding the blade(s) in the first place. But you'll still have to learn to adapt to the initial vibration upon startup.

//greg//

 

[Parakleta]

What is a stump jumper?

 

[teg]

A photo is worth a thousand posts... Got one of yours???

Stump jumper is the round part that the blades attach to... in the middle.

 

[Parakleta]

A photo is worth a thousand posts...

You should be able to see from the photo that the bottom plate is now bent, and the dent where the blade has swung back against the end of the shaft.

 

[gwdixon]

You should be able to see from the photo that the bottom plate is now bent, and the dent where the blade has swung back against the end of the shaft.

I haven't seen that design before but it is apparent how the blade could bind in that gap. Also, the blade could certainly not rotate 360 degrees.

If it were me, I'd weld a small piece of metal, maybe a large nut, onto the top of the blade about 4" or so from the attachment point to prevent the blade from rotating back into the gap. Some will not like this solution because of welding onto the hardened blade metal.

Rotate the blade until just before the bind point and decide where on the top of the blade the nut needs to be welded to prevent the binding. Do it to both blades to keep the balance.

Further, the mower (slasher) doesn't have a "stump jumper" and the head of the bolt is exposed to the damage that can be done on uneven ground. A quality mower has a rounded head on the bolt and is secured with a key in a reinforced shaft. Can't tell if that is the case from the photo.

If something is struck the blade will not rotate all the way out of the path but it wouldn't anyway with that design. I'd have to say that the design is not the best.

If it is possible to exchange that mower for a better constructed / designed one it would be advisable.

 

[Glen Watkins]

I would be talking to the dealer about it. Either it is assembled wrong or it is a terrible design. Look at Tegs photo and you will see how the blades are able to swing freely.