Procedure for engaging rotary cutter?

[JimParker]

So what's the best method for engaging my MX5 rotary cutter? I read one place to engage the PTO at lower-than-normal RPM, and then bring it up to speed. Another place says to engage it only at full PTO RPM. I don't want to burn up the slip clutch (the nominal reason for engaging at lower RPM), but I also don't want to overstress the engine (engaging at full PTO RPM really seems to "lug" the engine down a bunch). I've asked my dealer (waiting on e-mail reply), but wondered what you folks would recommend, and why?

Thanks - as always - for helping to further my education!

 

[RogerH]

My advice is to engage it at a lower engine speed then raise the throttle to operating speed. The must have enough speed so that engaging the PTO doesn't kill the engine (or almost kill it) which you will have to learn through experimentation.

My reasoning is that the start up shock load on both the tractor and implement are reduced at lower engine speed. And if a problem with the machine is encountered (perhaps it isn't clear of an object, there is an imbalance in the blades, your dog or kids appear on the scene) you can be more aware of your surroundings and get the PTO shut off quickly if the engine isn't at its loudest and fastest setting.

I don't think that turning the PTO on at full engine speed will hurt the tractor, but could lead to broken shear pins in any implement. I also follow the same procedure on my riding lawn mower. It reduces the shock load on the belts and they last longer.

 

[rdln]

Engage at lowest rpm and bring up rpm, its a good habit. I dont know how a 3320 pto engages but my GST meshes a lot quieter at low rpms compared to full tilit and another issue is the blades on RC may have relaxed and swung towards center when you last shut it off, if you engage at full pto the blades centrifuge so quickly the RC bangs and shutters violently.

essentially what Roger said but I have more posts so I must know more than he does........hahahahahahahahahahaa

 

[orlo]

I have an LX5 and for it and other implements they recommend engaging it at a low engine RPM and then speeding up.

I have to admit though that when I run any PTO implements I wish for a manual implement engagement clutch (Like the 2 stage on the 790/990) to ease the implement up to speed. The electric clutches used on all the newer tractors and even lawn tractors seem to engage much too quickly. I'd rather wear out the engagement clutch a little faster and stress the engine and implement less but that's not possible.

On this note, does anyone know if there is some sort of damper on the electric PTO clutch that you can adjust to slow down the engagement? I'd love it if I could adjust it to engage over say 2-3 seconds instead of just 'wham'.

 

[rico304]

Engage at lowest rpm and bring up rpm, its a good habit. I dont know how a 3320 pto engages but my GST meshes a lot quieter at low rpms compared to full tilit and another issue is the blades on RC may have relaxed and swung towards center when you last shut it off, if you engage at full pto the blades centrifuge so quickly the RC bangs and shutters violently.

essentially what Roger said but I have more posts so I must know more than he does........hahahahahahahahahahaa

hahahahaha

 

[RoyJackson]

Engage at a low (1200-1500 RPM) and have your foot on the throttle if the engine starts to stall. You can "blip" the throttle to prevent stalling.
Leave the RPM at 1200-1500 RPM for 8-10 seconds to allow the blades to extend and balance.
Increase the engine RPM smoothly to PTO speed and engage the gear your intend to operate in. If you're new to rotary cutters, I'd suggest you use a lower gear until you feel comfortable. If you're mowing an area you're not familar with (or have cut previously), use a low gear.
I really like using the cutter, but it's potentially dangerous. One is operating in an area that may contain a lot of debris under the brush. There may also be ruts or rises that can overturn a tractor (only time I ever came close to rolling a tracor was running up a sudden rise on one side while dropping into a shallow rut on the oppoite side..this is why one goes slow when running in brush)

 

[JerryG]

The electric clutches used on all the newer tractors and even lawn tractors seem to engage much too quickly. I'd rather wear out the engagement clutch a little faster and stress the engine and implement less but that's not possible.

On this note, does anyone know if there is some sort of damper on the electric PTO clutch that you can adjust to slow down the engagement? I'd love it if I could adjust it to engage over say 2-3 seconds instead of just 'wham'.

There are some tractors that have soft engagement. The engagement is actually staged so that the shock to the tractor and implement are greatly reduced. Both of the MF compacts that I have owned, you can start the PTO at full speed and the engagement is not abrupt. I wouldn't recommend starting it that way, but it still doesn't shock the tractor even if you do. Massey Ferguson and other AGCO family compact tractors are that way. I don't know if any other brands have this system or not. It would be interesting to find out if there are.

 

[JimParker]

Thanks for all the feedback. I just knew it couldn't be good for the tractor or the cutter to engage at PTO speeds... It just "felt" wrong.

And I already intend to operate in "low" range (HST) and go pretty slowly as I cut for the first time, and with the FEL lowered almost to the ground, with the bucket slightly curled... Last weekend I found a hole (fox?, coyote?, ??) that was abandoned, but it was a bit scary. The thing was nearly 2 feet across, and almost 2 feet deep. When the wheel went in the hole, I got a pretty good jolt (even though I was going pretty slow), but I was on relatively level ground... Made me realize (again) how dangerous that could have been on a slope, or at higher speed, or with the bucket full... I looked for the critter, but the hole was empty, so I filled it in. We'll see if it's dug back out when I return...

 

[Maxfli]

Maybe this goes without saying but I think the opposite is true as well. When Dis-engaging the Rotary cutter, I first slow the RPM way down, and then turn off the PTO. I don't have and overrun coupler on my PTO so that makes it easy for the unit to spin down.

 

[RalphVa]

Good advice from everyone. My owner's manual says to start slow, about 1500 rpm, and then speed up. Says starting at full speed could break the shear bolt.

I got in the habit of slowing down to engage the PTO on my old Gravely, whose engagement was a gear mechanism. It just wouldn't go in unless you slowed down. On the Gravely, one had to slow it down to stop it, too. Otherwise, the bloody blade would absolutely spin forever!

I do this engagement and slowdown to shutdown on my chipper/shredder, too. It's easier on its belt drive that is used to run the speed up on the hammer mechanism. The belt slips a lot if you don't slowly slow it down before release from the PTO. Actually, what I should do on it is to put the PTO into the "mid" PTO selection, this would allow the PTO to free wheel.

Ralph