Identify this rotary cutter please.

[rickdowe2]

Hi, I have a rotary cutter that I bought years ago and attached it to my John Deere 50. I was young and stupid and decided I could mower heavy brush. I spent the next few years with the tractor broken in half repairing the transmission. It does have a shear pin but who knows if it is the correct one and exactly how do I know how much pounding this tractor can take before it needs to shear. One thing I have not checked yet is if the shaft connection is seized where the shear pin is located . I will be looking at that soon. There is a tag with numbers stamped each corner ( 225044……99379) but no other markings. The box is a lot larger than the blade. The blade measures 60” across. If anyone has one like it and could give me the information on the shear pin that would be helpful. Any help or thoughts will be appreciated.Thanks

 

[38 Sears Roebuck]

Two things here. Number one is that graded bolt on the mower shaft gear box needs to be replaced with the correct shear bolt as you have stated. Number two I would be running an over running clutch attached to the tractors pto shaft. Just my 2 cents.

 

[rickdowe2]

Hi, I concur with both those statements. I took a quick glance at clutches in tractor supply a while back. Are those preset to a certain torque? Is there a scale that you use like on ski binding for the tractor you are using it on?

 

[38 Sears Roebuck]

 

[38 Sears Roebuck]

I'd try this before you go tearing up the pto on the tractor again. You'll need to make modifications to your pto shaft. Don't ask me how I know that. I tore up a system on a Ford 2000 one time pulling a pto driven manure spreader.

 

[BarnyardEngineering]

Slip clutches are adjustable so you can tune them to your exact needs.

The shear bolt is currently a Grade 5, as denoted by the three tick marks on the head. Rotary mower shear bolts are commonly Grade 2 or Grade 5. If yours did not break it may require a Grade 2 (no tick marks on the head).

Also consider that your John Deere 50 is approximately 70 years old. It has seen some things and done some stuff. There is a good possibility that the PTO shaft was on the verge of giving out.

 

[rickdowe2]

I have no desire to do heavy bush hogging with it mainly keep down the grass and shoots that pop up. I am thinking the slip clutch selection might be based on the output shaft rated hp and if it is than I would select a lower hp clutch.

 

[Jim.ME]

To install a slip clutch you will need to rework the driveline at the gearbox end. A slip clutch is mounted on the implement gearbox, not the tractor's PTO shaft.

You change the torque required to make the clutch slip by adjusting the bolts with the springs on them.

Use a grade 2 bolt to make your shear pins and be sure the yoke is not frozen to the gearbox shaft.

 

[rickdowe2]

The best I can do is to use the existing shear pin as a guide and use grade 2 like you said and cut the grooves deeper than normal( i have a lathe) and try if it shears sooner than I think, than redo the pin with a shallower cut. Thanks for the info on the slip clutch and thanks to everyone for your input.