Rip - Your Chipper

[woodlandfarms]

Can you post some pix? You said you adapted it and I want to see all that you did.

Carl

 

[Rip]

Carl, I am not up to speed on posting pics on this site, but I can email direct to you, and if you can re-size, whatever and post here that would be fine.

PM me your email,

 

[3238dpw]

I am not up to speed on posting pics on this site

Now wait a minute!!!! You will just have to learn! He isn't the only one who wants to see these.

Rip, can he have permission to post them once you send them to him, that way we can all enjoy

 

[Rip]

Absolutely ! ! !

Still waiting on Carl's email though.

 

[woodlandfarms]

Sorry.. I just sent you personal. I am finally back in Woodland for the week. I spent the entire day just looking at my tractor... Thinking of how much I could do with it, and then looking at the mud and rain and realizing I may have to limit my winter activites unless I buy chains...

 

[woodlandfarms]

Ripped from Rip....

Funny you should ask, 'cause I just did about an hour of chipping yesterday and took these pics while it was still hooked up.

I fabricated the mount like a mini-fork with the QA mount tilted about 30 degrees forward - very important.

I removed the chipper housing from the trailer it was on and the pulley and belt guard. No modifications, so can put everything back like it was if I want.

The hyd motor is sized for the PT PTO hyd flow & pressure (15 GPM @ 3,100 psi in my case) to run the chipper disc direct at about 2000 + RPM at full speed. Had a machine shop fabricate the three-sided box-motor mount to shield the flex coupler and line everything up. It used the existing pillowblock bearing bolt holes on the chipper housing.

Installed a one-way check valve in the loop you can sort of see on the left in the picture so that when you turn the PTO switch off, the disc will still be spinning fast and will turn the motor into a pump until it spins down. The checkvalve allows for this so no damage or shock to the system occurs. This may not really be neccesary since the blades of a mower would do the same thing and the PTO circuit may already allow for this, but the 140 lbs. chipper disk has so much more momentum that I felt better-safe-then-sorry.

I start with the engine at about 1/4 speed and turn the switch on, then ramp up the engine to full and chip away. I can bog the system a bit sometimes, but it recovers almost instantly. I ramp the throttle down to about the same before turning PTO off, but not sure that matters.

If the wind trys to blow chips back on the tractor, may drape a tarp over front part to reduce clean-up. Took me over 1/2 hour yesterday to blow most of the wood dust out of the engine tub and foot wells.

 

[woodlandfarms]

OK.. So WAY cool!!!!! I had never thought of gutting the pulley system off...

Which Bearcat is this? And how big of a limb can you get through it?

Carl

 

[J_J]

OK.. So WAY cool!!!!! I had never thought of gutting the pulley system off...

Which Bearcat is this? And how big of a limb can you get through it?

Carl

Rip, Did you start with a 3 or 4 in chipper turned by the tractor PTO?

I have a PTO Bearcat chipper also, and was thinking of driving the unit with a hydraulic motor using the step up pulleys. What is the rpm on the hydraulic motor, and shaft size?

 

[MossRoad]

Excellent job!

 

[Rip]

This was a BearCat Model 73420 trailer-mounted, manual feed, 5" throat (I think they rate it as a 4" however) and was powered by a 20 HP Honda.

The unit as purchased worked well, except that I was spending too much time & effort hauling slash to the chipper as most areas are too steep or rough to bring the chipper to the slash.

Thus the conversion, which has worked really well since I can now bring the chipper where ever I can drive the PT - still not everywhere around here! With the big diesel behind it, it recovers from any bog-down very quickly.

When it was powered by the Honda, the disc was running at 1800 RPM, but research indicated that others often run a bit faster, so I targeted 2000 RPM. If you read my other post on the treadle topic, I discovered my engine was not getting to full speed even though the throttle lever was at max. The chipper really sings now !

J J - I have seen others do the same conversion to PTO chippers also. Just remove the entire pulley & belt components and go from there. With LoveJoy or other flex couplers, you can have different shaft sizes on motor and driven shaft, so does not matter. That is what I would have done if I had been starting from scratch.

 

[SnowRidge]

Excellent job!

Yes, it has that Wow factor. Really nice.

 

[MossRoad]

I've often wondered what size chipper a PT425 could run with its 8GPM@2500PSI rating. I think it works out to something like 11HP.

 

[Rip]

Yeah....this particular model is probably a bit too much for the Green machines. But BearCat also sells the same chipper head with a 13 HP Honda, so not too far off. The next step down from BearCat and others may be just about right.

This model was right at the cross-over point between the manual-feed and power-feed series, and in fact this head is also available with power feed (wish at times I had gotten it).

Most of the PTO shaft-driven chippers are likely to be in this size catagory or above (except perhaps DR). Still, many suitable units around I would guess. Also many self-powered units sitting around with a bad engine. Think eBay, Craigs List, yard sales, etc!

Get some advice from a hydraulic pro regarding the motor.....there are many that will work fine if sized right, but some will be better than others.

Good Luck

 

[woodlandfarms]

Well, the wife is in LA dealing with our kitchen disaster... I sent her a funny conversation in this forum on how to lie to a wife about equipment. Then I dropped her a line on buying a BETST Chipper (they are down the street and claim they upgrade their Jinmas... ) And they have their 6" chipper for $300 less than usual. Funny, she said follow the 3 day rule (If it is the garage unnoticed for three days it is "that old thing and something I bought a long time ago")

Well, you can imagine my excitement. And then the ugly realization that I am going to have to adapt the PT to this device.

Rip, your notes have been fantastic. I wanted to get from the group a couple of things.

I like the idea of direct connecting like RIP did. There seems to be a design issue in the Jinmas on how the system powers from the PTO to the system.

But, I have also pondered the ease of just creating a system that hooks up onto the PTO shaft.

So, first, anyone want to weigh in on this issue?

Also, in Rips desing he put in a bypass valve. As he said his mower does not have one. Do you think I would need to build one?

Carl

 

[woodlandfarms]

So, it is 2 AM and I was just sitting around looking at Surplus Center website and I finally figured out what JJ was yacking about with the Tech Support page.

So looking into a 540 RPM moter and a 2000 RPM Motor...

According to the charts. I need a 7.7 CU Inch motor for 540 RPM but it give me 3800 lbs of torque. If I go with the 2" motor for 2000 RPM I get only 1000 lbs of torque. Seems like it is a no brainer that I should stick with a 540RPM.. But there are all the step up belts and such... And loss of energy through that as well...

Anyone want to weigh on the physics of all of this...

 

[sawdust_maker]

So, it is 2 AM and I was just sitting around looking at Surplus Center website and I finally figured out what JJ was yacking about with the Tech Support page.

So looking into a 540 RPM moter and a 2000 RPM Motor...

According to the charts. I need a 7.7 CU Inch motor for 540 RPM but it give me 3800 lbs of torque. If I go with the 2" motor for 2000 RPM I get only 1000 lbs of torque. Seems like it is a no brainer that I should stick with a 540RPM.. But there are all the step up belts and such... And loss of energy through that as well...

Anyone want to weigh on the physics of all of this...

Its 20 years since grad school for me, but...

If you then step up this motor using belts to get a delivered 2000 RPM, the torque will drop by a factor of roughly 4. Except, as you point out yourself, for the losses due to the belts and pulleys. There is no free lunch here. So you will end up with less than that. The direct drive motor would be the best option for maximum delivered power, and it already delivers reasonable RPMs, unless you wanted the shock absorbing abilities of a belt drive.

John

 

[J_J]

So, it is 2 AM and I was just sitting around looking at Surplus Center website and I finally figured out what JJ was yacking about with the Tech Support page.

So looking into a 540 RPM moter and a 2000 RPM Motor...

According to the charts. I need a 7.7 CU Inch motor for 540 RPM but it give me 3800 lbs of torque. If I go with the 2" motor for 2000 RPM I get only 1000 lbs of torque. Seems like it is a no brainer that I should stick with a 540RPM.. But there are all the step up belts and such... And loss of energy through that as well...

Anyone want to weigh on the physics of all of this...

Carl,

Why not put this on the PTO shaft and you have another hydraulic source for the chipper.

Surplus Center Item Detail


I didn't understand the 2" motor thing.

 

[woodlandfarms]

Carl,

Why not put this on the PTO shaft and you have another hydraulic source for the chipper.

Surplus Center Item Detail


I didn't understand the 2" motor thing.

First, I should have put 2 Cubic Inches..

Second, this is exactly what I was looking for. This said, its specs out a bit low for my appliccation. I have 3100 PSI at 18GPM. Or is that not really a factor in this application. Sorry for the ignorance, just learning...

Carl

 

[Rip]

Carl, Considering the chipper disc itself, you are going to be much more efficient driving it directly rather than through any part of the PTO belt system. The power losses through the additional belts, pulleys and shafts will be significant.

The tractor hydraulic PTO output of nominal 3000 PSI @ 18 GPM is the input you have to work with in sizing the chipper drive motor. You also have a case drain available in the event the selected motor uses one.

I do not have any mower for my PT, but I think the larger ones use a case drain (third hose). I do not know if they use an external bypass valve to allow it to "free-wheel" when the PTO is switch off. On the one hand it may not need it since the mower blades have much lower inertia than the heavy chipper disc, or the PTO valve on the tractor may already take this into account. You could check with Terry. I put it in just-in-case and knew it would not hurt.

I immagine the Jinmas has hydraulic power feed (sort of wish mine did). This can probably be modified to tap off of the main PTO flow, or perhaps use the third aux hydraulic cylinder circuit. With the machine in front of him, a knowledgable hydraulic tech should be able to figure the best solution in 10 minuites. On-line and from a distance, it may be more difficult.

You could ask the folks at the dealer you would be buying the chipper from if they have done similar hyd conversions in the past. There is nothing unique about the PT in this regard.

Or best yet, perhaps they already have a SkidSteer version, which may just need a PT mounting plate instead of the SS type and mating hyd fittings.

The PTO hydraulic pump JJ linked to from Surplus Center is intended to provide an auxilliary hydraulic power source from a tractor PTO shaft when the tractor otherwise does not have an available hyd source. It would not be appropriate for this application.

 

[Bob999]

The tractor hydraulic PTO output of nominal 3000 PSI @ 18 GPM is the input you have to work with in sizing the chipper drive motor. You also have a case drain available in the event the selected motor uses one.

I do not have any mower for my PT, but I think the larger ones use a case drain (third hose). I do not know if they use an external bypass valve to allow it to "free-wheel" when the PTO is switch off.

I have a 72 inch mower for my 1845. It has a case drain but no external bypass valve.