Cutter shakes like crazy

[bindian]

So, snow is gone and finally got to do some serious hogging on the field. Took the 5035HST out with the 7' HD Mahindra cutter and for the next couple hours it was smooth going. Then, all of a sudden the thing starts shaking like crazy. I didn't hit anything, it just starts shaking. I shut it down, lifted it up and there is nothing tangled in the blades, no missing parts, no broken blades, no bent blades, nothing, perfectly clean, it just shakes like ****.

Any ideas?

If a new cutter was cutting fine and smooth for a few hours then started shaking..............I would go over it and tighten every nut and bolt I could find. Sure sounds like something came loose.
Check the 3PH over for something loose also.
hugs, Brandi

 

[madmax28]

I've had the same problem on my smaller setup. What I found to fix mine was changing the rear height of the mower. The driveshaft u joints didn't have enough angle on them and after running a while the driveshaft was causing vibration. After stopping it and looking everything over I noticed the driveshaft was almost straight from the tractor to the cutter gearbox. Adjust the tail wheel height and its ran good ever since. Good luck.

 

[Ram4x4]

Ok, an update. Last Saturday I decided I was going to remove the blades and weigh them to see if there was a big difference in weight. I got out the impact wrench (and I did have a socket big enough for the nuts on the blade bolts), loosened them up, but found that the blade bolt/studs are evidently pressed in as well (or some sort of very tight fit). Decided I didn't want to pound them out, so I put the nuts and lock washers back on and tightened them back down.

I then backed the tractor in and hooked up the cutter. Crossed my fingers and fired it up. Voila, no shake. So, I mowed for a couple hours and after I was done, I lifted the cutter and now there was some shake, not near as bad as previously, but some shake none the less.

Weird. It was dead smooth when I started, and then shaking some after mowing. Nothing built up on the blades, totally clean underneath (very dry weeds and grass, no mud, so makes sense).

I've gone over the cutter and checked every bolt and nut, nothing loose. The shaft is not bent (OMG that plastic safety housing is a beotch to get off), U-joints are all good, no bent blades, no missing sections of blades, no big gouges in the blades, nada.


So, I guess as long as it doesn't start shaking like it did the first time, I'll just use it. Just strange that it starts out totally smooth, then starts shaking after use.

 

[pjbci]

I know you said you chked every bolt and nut. Did you check the blade bolt again to see if one of them may be working loose? Im sorry if this is a stupid question, just find it odd that it didnt shake after you tightend em but shook a little after use. A problem like that would drive me bananas trying to solve it.

 

[Ram4x4]

Actually, yes. Everything is tight. The parts that should be loose are nice and loose (blades swing freely and easily, tail wheels, etc). U-joints have no play and don't bind. No evidence of heavy clutch slip on the drive line (actually, I think I may need to adjust the slip clutch as it looks like it is tightened to the max and there will be NO slip).

Yeah, it is kinda driving me nuts. I hate stuff like this. Even though there is not much shake, I mean, it's not exactly a precision piece of equipment, I don't expect it to spin so smooth I feel like it's a cadillac, but any shake like something is out of balance is just adding stress to parts somewhere.

In affect all I have done is remove the blade nuts, put them back on and re-hook it up to the tractor (meaning the collar splines on the cutter's shaft are probably not in the exact same splines on the PTO shaft as last time).

I'll see what happens next time I hook it up. If it doesn't shake on start up and only has a very slight shake after use like the other day, I am just going live with it. The 6' cutter and old David Browne 880 I had when I was in Texas shook and that thing never gave me one problem in the 12 years I had it. Sheared a few bolts on the drive line, but the cutter never broke down once...and I abused the **** out of it.

 

[SPYDERLK]

Ok, an update. Last Saturday ... ... I then backed the tractor in and hooked up the cutter. Crossed my fingers and fired it up. Voila, no shake. So, I mowed for a couple hours and after I was done, I lifted the cutter and now there was some shake, not near as bad as previously, but some shake none the less.

Weird. It was dead smooth when I started, and then shaking some after mowing. Nothing built up on the blades, totally clean underneath (very dry weeds and grass, no mud, so makes sense).

Could be a driveline oscillation due PTO angle. Does it shake worse the higher its lifted?
larry

 

[Ram4x4]

No, when it is shaking it doesn't matter if it is sitting at cutting height or lifted all the way up, shake doesn't change (doesn't get worse or less).

 

[crackercap]

I think the problem is it's out of balance and I have this problem occasionally I follow the procedure that Aching Back mentions and usually that's the solution. It sometimes takes a try or two by bringing it up to rpms very slowly.

 

[woodway449]

Maybe one of the pto shafts is out of balance or has a u-joint out or going out.