Chipper What happens if I hook up too much HP to a Woodland Mills Chipper?

[JethroB]

I was going to let this go but I can't help myself.

The question isn't if that scenario will take weight off the front axle, it's when will it take weight off the front axle and when will it add weight to the front axle? Use your scenario but add an additional 20,000 lbs. to the bucket. The fulcrum just changed from the back axle to the front axle and your 10,000 lbs. on the back added to the weight now on the front axle. But we all know it is absurd to think anyone would ever actually put any amount of load in the bucket of their tractor.

Back to your regularly scheduled program.

Interesting counterpoint and example. The weight is going ‘somewhere’. Thankfully the engineers are ahead of us with the hydraulic relief valve.

 

[Reb954]

I'm glad to see folks have a sense of humor.

 

[5030]

Before I sold it (for what I paid for it), I ran one of those Chinese chipper on the back of my M9000 Kubota which is 82 PTO horses and the chipper was rated for 30 PTO input maximum. I just added a Weasler slip clutch to the chipper input and set it to slip at a moderate input. 3 years and never an issue. I did have to add extension legs to the chipper body as it sat too low for the M9's output stub as it was built for a compact tractor.

 

[CoyPatton]

That really isn't true...

The smaller hp tractor most times will slow down a bit before shearing a pin. Many times it gets through the rough spot before the pin shears.

With the much higher hp tractor, for the same size shear pin, is has to much hp on tap, it shears the pin much faster and you go through more pins.

I've seen this happen many times...

SR

Agreed, while there is some truth to the shear pin protection from HP, I expect that you will shear pins frequently with near double the HP.
As for running at a lower RPM, you certainly can, but unless the tractor is equipped with an economy PTO feature, you will not obtain 540 RPM PTO speed. You may be fine with not being there but then again you may not!
You are in the position that you can play to see if it will work at an acceptable performance level and only lose the cost of some shear pins. If that is ok try it, but also start shopping for a chipper in the HP rated area of your new tractor. That way the decision making on purchase is at least jump started.

 

[Steelkilt]

Thanks everyone for the great information. I looked on the Woodland Mills website for shear pins as it seems I will need some for this experiment. Surprisingly, I did not see any available for sale. It was already after hours so I left an email. My 50hp tractor already burned one pin so I am on the last supplied of the two that came with the chipper. I'll find the WC68 manual tomorrow and look at the remaining pin in the PTO shaft to try and figure out what size is needed.

 

[Citydude]

With the hydraulic drive feed rate, I wouldn’t be concerned about the HP at all.

 

[oosik]

Regarding shear pins/bolts. Some chippers, like my Wallenstein, recommend use of Wallenstein shear bolts only. It's a specially designed bolt with a grove cut round it. This is where the bolt will shear. Some will specify their own bolts or an equivalent grade machine bolt.

By far - the equivalent grade machine bolt will be MUCH less expensive. The special Wally shear bolts are around $6.75 - as I remember.

If you are going to be snapping many shear bolts - it could be worth your while researching this.

 

[Egon]

Agreed, but the post I was quoting was so general, it just needed to be corrected.

Using a chipper, other than when first starting out, a bigger hp tractor shouldn't be a problem. You just have to be carful not to engage the pto too forcefully.

SR

Nothing vague about the post. When the shear pins rating is exceeded it breaks. It really doesn稚 matter what the HP is.

 

[CobyRupert]

The question becomes: Does the sheer bolt protect the equipment or the tractor’s PTO?
Using the extreme examples: 10,000 hp on a 10hp (rated) chipper, one hopes the bolt is sized for the 10hp chipper. (It should be).
The opposite is probably a problem: A shear bolt for a 10,000hp chipper won’t protect the PTO for a 10 hp tractor when it comes to an instant stop. Hopefully the PTO is rated to take the full stall shock load of the engine.
IMHO running a 20hp rated chipper on a 100hp tractor is better than running a 100hp chipper on a 20 hp tractor/PTO.

 

[k0ua]

The question becomes: Does the sheer bolt protect the equipment or the tractor’s PTO?
Using the extreme examples: 10,000 hp on a 10hp (rated) chipper, one hopes the bolt is sized for the 10hp chipper. (It should be).
The opposite is probably a problem: A shear bolt for a 10,000hp chipper won’t protect the PTO for a 10 hp tractor when it comes to an instant stop. Hopefully the PTO is rated to take the full stall shock load of the engine.
IMHO running a 20hp rated chipper on a 100hp tractor is better than running a 100hp chipper on a 20 hp tractor/PTO.

You bring up some very good points.