Rotary Cutter rotary cutter question

[HD Labs]

Thanks Soundguy and CDsDad. I do understand how it works a bit better now. I will be using the cutter with a Ford 8n and Massey 240 (23HP-34HP I belive). DOes that have any bearing on slip clutch shear bolt issue? would one be better over the other with the HP tractor I will be using vs. cutter/gearbox size?
I am beginning to beleive that for my application I will be better off with shear bolt. Thanks again.

 

[woodlandfarms]

So, can you double your protection by using a slip clutch and some sort of sheer pin together?

 

[Farmwithjunk]

So, can you double your protection by using a slip clutch and some sort of sheer pin together?

Which ever one is "set" to let go with least effort will win out. no real advantage gained IMHO.

 

[CDsdad]

If your slipclutch malfunctioned a shear bolt would prevent damage.

If your bolt didn't shear a slipclutch would prevent damage.

I've never seen anything with both, though. To me the ultimate protection is a shear bolt as long as it's the proper grade. I do own a bushhog with a slipclutch, though. I've never had a problem with it, works fine.

 

[Soundguy]

As Farm and CD points out.. When a stoppage occours.. whichever is the weakest of yuor driveline components will let go first. That may be the shear pin if the clutch is stuck or misadjusted.. It may be the clutch. So.. yes.. i guess you could say a clutch held on by a grade 2 bolt gave you the benefits of both devices, and the limitations of both devices.. with the exception that if the slip clutch malfunctioned.. the bolt would shear.

IMHO.. the engineers that design the torque limitation on a device know about the device. That is.. if the engineer set it up to be shear pin protected.. then.. I'd have to think that the shear pin met at least -minimum- protection standards.

FWJ is correct when he points out that you see slip clutches on many o fthe HD mowers.. and virtuall all mowers over 6' - 7'.. etc.

My take on that is that the larger the mower.. the larger the tractor.. and the more torque the driveline will be under when cutting... thus making a shear bolt less effective as it may pop too soon when experienceing a heavy load while cutting thick material..

The biggest thing to remember is that you MUST service your slip clutch at regular intervals to keep it functioning correctly.. and.. it is a friction based device... DO expect it to eventually wear out.. just like brake pads.. or transmission clutches.. ( I'd expect to get alot of service years out of a slip clutch that wasn't abused heavilly, and was maintained correctly.. )

Soundguy

 

[RalphVa]

My Gravely brush hog had a slip clutch. My current JD LX4 has a shear bolt. Went the shear bolt route because my neighbor's 30 year old bigger JD uses only a shear bolt, and it didn't break any gears,etc. with lots of different people using it over the years. I've only had to replace the shear bolt twice in 2 years on my LX4. It's a really simple job once I cut the silly plastic sheath away that projected over the U-joint and back over where the shear bolt is. The first time, there was no bolt to remove or anything. It was just gone. The second time, the main part of the bolt was still in the shaft. Just had to poke it out with a screwdriver.

Slip clutches just work like the clutch on your car, pickup or old tractor. I just has a disc held in place against rotation by some springs. The spring tension is adjustable with some lock nuts. You need to carefully follow the instructions for resetting the spring tension. I never had to do this on the Gravely, neither on the internal slip clutch built into it nor the couple of slip clutches on the older implements that I used it on.

Ralph

 

[Neophyte]

If you are only cutting a couple of times a year, I wouldn't worry too much about which rotary cutter you choose. An economy model should work fine for your needs. You may even want to look for a used cutter.

Slip Clutches can easily be added later on. Save your money and try the shear bolt route. If you don't like it, you can add the slip clutch later.

I will say that in the past couple of days I must have gone through about 7 shear bolts while rotary cutting (rocks, 2" trees, ground, etc.). Having to stop so often can be pretty frustrating. I was using Grade 2 bolts on my Howse 500 even though it actually calls for Grade 5. Many people out there will use Grade 5 bolts even without a Slip Clutch. I couldn't take it any more, so I finally ventured to Grade 5. Start with Grade 2 and if you find yourself replacing them too often, then you can always move up to Grade 5 . Whatever you do, don't venture beyond Grade 5.

Like others have mentioned, keep some spare bolts on your tractor along with the tools you need to change them.

You may need to special order them online or through your local fastener company, but you could also find a Grade BB bolt that falls somewhere between a Grade 2 and Grade 5. Does anyone know of a good source for Grade BB bolts?

Whichever RC you get, make sure it has guards on the front and rear. If the cutter does not have them, you can make some on the cheap using cut up mudflaps (Soundguy's good advice).