Help me convert my chipper to 3pt

[arrabil]

So I'd like to convert my 10HP chipper to 3pt mount and either PTO or hydraulic power. Welding up the 3pt mounts is the easy part. I'm not quite sure what to do with the drive mechanism.

Its a Tecumseh HM100 engine. The tech guide says its 3400rpm. The parts guide shows the engine is directly connected to the chipper blade.

My tractor has 20 PTO HP and 7.3gpm hydraulic flow at the Power Beyond ports.

If I go PTO, what do I do to raise the 540 PTO rpms to 3400 and where do I get a PTO driveshaft yoke for the drive mechanism? Do I need a PTO gearbox? Or a pulley setup? I can't figure out where to start here.

If I go hydraulic, I'm looking at this motor as it seems to (more or less) match the specs I have and need (there is also a 0.75 cu-in motor but its a little less than I need). I'll need a pulley setup to double the motor rpm from the rated 1800. I get the feeling this motor isn't going to be powerful enough and that I will need to drop the whole idea of hydraulic power.

Any help and experience would be appreciated!!! Thanks!

[And please, I don't need the reasons why it would be better to keep it the way it is or why I should buy an already made one. I know what I want to do and why. Just need help figuring it out.]

 

[MikeInEburg]

Hydraulic really isn't a viable option for you - it would take a huge amount of both flow and power to run a chipper from hydraulics.

So, a PTO drive with gearbox that provides 6.2:1 (or is it 1:6.2) gearing. If you can incorporate some type of flywheel, it will allow the chipper to use stored energy to get thru the rougher chipping situations. A flywheel from an old baler would be good - just remember to shield it from inquiring body parts. Oh - and you need to make sure that the chipper still turns in the correct direction after the gearbox.

You also need to consider the driveline physical pathway.

Good luck!
Mike

 

[arrabil]

By "driveline physical pathway" I take it you mean where the PTO shaft goes? And safely? That won't be a problem; with the engine gone the platform has lots of room all facing the right direction.

I was looking at parts breakdowns of the Woods chipper yesterday. They use a double pulley system to up the rpms and they only chip at 2400. I was thinking I could get away with a 12" and 2" pulley if needed.

So the real question is: where does one find PTO gearboxes? They make these things in all different sizes?

 

[MikeInEburg]

If you're looking for used, I'd use a gearbox from a mower or similar implement. If new, go to a dealer and inquire.

Mike

 

[ModMech]

A good used box off a shredder shoud be more than enough for a 10 HP chipper.

I looked at doing this with our Craftsman chipper after a can of blended fuel fouled the carb when stored over the winter (didn't realize it was bleded).

My plan was to mount the chipper to a drawbar ($25), install a pair of pillow blocks where the engine *was*, to connect the PTO shaft to and find a pulley that was about 5 times the diameter of that on the engine that I removed. I was going to mount the PTO coupler to one side (recoil side) of the chipper and the pulley on the drive side which allowed me to re-use the belt guard.

In this configuration, there was no need for a PTO gearbox.

 

[RoyJackson]

By "driveline physical pathway" I take it you mean where the PTO shaft goes? And safely? That won't be a problem; with the engine gone the platform has lots of room all facing the right direction.

I was looking at parts breakdowns of the Woods chipper yesterday. They use a double pulley system to up the rpms and they only chip at 2400. I was thinking I could get away with a 12" and 2" pulley if needed.

So the real question is: where does one find PTO gearboxes? They make these things in all different sizes?

Doesn't look like you'll need a gear box if the chipper's knives/flywheel are perpendicular to the driveshaft. This would depend on how the original motor was situated on the chipper frame. Since you're doing a total rebuild, you can set the chipper knives/flywheel however you want (on the frame).

By keeping the knives/flywheel perpendicular to the drive shaft (substitute PTO shaft), looks like all you'll need would be pulleys of the correct size to increase the knives/flywheel speed to what you want (that is, from 540 RPM to 2400?). Then, of course, a belt that can withstand that speed and inertia as well as some kind of tensioner to keep that belt tight (but not too tight). If my logic is correct, you won't need a gear box unless you need to change the drive shaft (PTO shaft) input direction.

I've attached the parts breakdown from the Woods 5000 chipper/shredder. As you can see, there is no gear box...just two pulleys (and bearings/pillowboxes). IIRC, the flywheel (which holds the chipper knives as well as the shredder assembly) weighs around 125 to 150 lbs. If you add a flywheel, you want to ensure the entire rotating assembly is balanced.

Of course, the next question is, can your current chipper handle a doubling of input horsepower? I have no idea about that...

 

[BHD]

IMO, I would think that 2" pulleys would not have enough surface area to properly transmit the power to the chipper shaft, unless you went with a 4 pulley system, up that to 3" and I think you would be able to get by with 2 "B" belts,

My first thought was sprockets, but to protect the tractor from shock loads or jamming you much better off with the belts as they will give and slip and protect the PTO transmission, a slip clutch may be desired as well,

but belts and that Idler tension pulley would be the way to go, IMO

 

[RobKinNH]

I've actually looked at doing this in the past until I found a used one. Look at a Mighty Mac by Mackissick chipper. They had motor run models and PTO models (what I bought). The PTO model is identical to the motor run model except its run off the tractor. PTO shaft, 2 pillow block bearings, large 2 belt pulley on bottom and small 2 belt pulley on input shaft.

 

[arrabil]

What do you guys think of running it at lower RPM? Its rated at 3400rpm but will it really chip worse at 2400rpm?

And while I definitely don't want to stall the tractor, why isn't it stall protected the way it sits? In fact I stalled it on some vines a couple weeks ago.

Is a PTO slip clutch enough protection against stalling the tractor? Reason I ask is that I'd really like to investigate using gears instead of belts. It would make it so much easier to build.

As to whether or not it can handle double the input HP? Its a pretty strong design from what I can tell. As long as I don't try to stall it out all the time I would think it wouldn't know any different. I was thinking if I gear it 6:1 and then run it at a lower speed that would be better too.

 

[RoyJackson]

What do you guys think of running it at lower RPM? Its rated at 3400rpm but will it really chip worse at 2400rpm?

Is a PTO slip clutch enough protection against stalling the tractor? Reason I ask is that I'd really like to investigate using gears instead of belts. It would make it so much easier to build.

Personally, I think it'll clog up at anything less then 2400 RPM, but that's nothing more then an opinion. You could always change the gear ratios to increase speeds if it turns out you need faster movement through the chipper.
And, I don't think gears would offer the protection that belts would. If it does clog, the belts would likely slip, gears won't. Odds are, something will break.

What is the capacity of the gas powered chipper? 3 or 4 inches? Do you expect to increase that capacity by going to a PTO driven chipper?

As far as the slip clutch...definitely. You'll have to experiment to figure out how much slippage you want (to protect both the tractor and chipper).

 

[arrabil]

Roy, you lost me a little... I agree the belts offer far greater protection than gears, which is why I was hoping a slip clutch would be the solution. Is that the case? Or does a slip clutch do something different than I'm thinking? [Can't say I'm 100% on what a slip clutch is as this point.]

I could also add a shear bolt. Surely a 1/4" shear bolt would offer enough protection. They're bigger than that on the 59" snow blower.

The capacity is 3". I do not want or need to increase the capacity. Anything over 3" is firewood. And realistically, the thing can't chip 3" hardwoods anyway. I just use it for the yearly brush.

 

[joes_427_vette]

Bought a used 8" pto chipper for 2k. I found several to pick from. By the time you deconstruct and rebuild this one at 50 cents an hour one would be over the 3k mark. Sell what you have and buy one manufactured. Libality and safety wise your much better off.

 

[BHD]

a slip clutch is a device that is designed to allow a shaft to slip or break loose once a given amount of torque is reached, there are a number of different methods, used, some use a "ratchet" normally two mating surfaces with a spring on one so once a given torque is reached it will bump across the face of the mating surface,

there are friction disks, where a number of friction plates, and steel disks are compressed usually by a series of springs and can slip if things reach torque or shock,

and there is a shear bolt method that the bolt shears and lets it run with reseting it self, (seen in pothole diggers and other machines where a shock load is possible but not common, and it is cheap,

the belts or the friction clutch method would be my suggestion, belts would be best IMO,

the biggest problem with slip clutches is that many people will keep tightening them when they slip, and when tightened up they no longer offer protection, or as much,

a picture of a friction disk slip clutch,

 

[arrabil]

BHD, that would be perfect! I could use 1" rod (or whatever diameter the one end is) and have a PTO connector on the other.

I understand why a belt seems best, but really, if the slip clutch is properly adjusted what makes it different than the belt safety wise? Augers aren't belt driven. Neither are snowblowers. And yet both are used without worry. In fact, the rod end of the slip clutch could be attached with a shear bolt and then its double protected. No?

I'm gonna have to look for some gearing systems tomorrow. Know where to find a 6:1 of those?

 

[RoyJackson]

Roy, you lost me a little... I agree the belts offer far greater protection than gears, which is why I was hoping a slip clutch would be the solution. Is that the case? Or does a slip clutch do something different than I'm thinking? [Can't say I'm 100% on what a slip clutch is as this point.]

Since BHD did a great job describing the function of a slip clutch, I'm not going to repeat it.
When I wrote you'll have to experiment with setting the clutch, if you use gears (rather then a belt or two), you may want to set the clutch to slip a bit quicker to reduce the shock load on the chipper's drive gears. The belts, if you used them, would provide a degree of protection by slipping...gears just break teeth.
So, bottom line is, you want to set the clutch so it's sure to slip before any major stoppages by the chipper jamming.

You do have a good point about the auger and blower gear drives though!

 

[Craig Clayton]

Dear Sir
I did a conversion on a 3pth chipper to run on a garden tractor, and the chipper can be changed back to 3 pth just as easily.http://www.tractorbynet.com/forums/customization/165827-5-chipper-shredder-garden-tractor.html. It is listed under 5 inch chipper shredder.
Craig Clayton

 

[beenthere]

Check out sponsor Surplus Center surpluscenter.com for gear reductions. Don't know if driving them from the output end to increase rpm is an option, but SC has a lot of different ones...inline as well as right angle.

Surplus Center

 

[arrabil]

Roy, I was thinking I'd adjust the slip clutch to the bare minimum tension that allowed it to chip. I could tack weld it in that position too.

Craig, thats totally awesome! And beyond my patience level unfortunately.

Beenthere, I was looking at that stuff last night. I do have to figure out if they can be used in reverse. All over the net they have reducers, but I don't see any multipliers. Surely, gears can be run in either direction! Surplus Center doesn't have any rated to 20 input HP either way though.

I found a thread on a PTO Welder that is the same problem as mine.

I probably need to learn about making my own sprocket setup. And I should probably consider how I could run this from the mid-PTO so I only have to do a 1:1.5 step up. I have two different length driveshafts from the snowblower then too.

This all really depends on finding a proper gear box now...

 

[beenthere]

Don't think I'd tack weld a slip clutch.
When it slips, some wear of the clutch happens. That means at some point in time another adjustment needs to happen.
Also, with a slip clutch, sitting un-used will/can cause the plates to stick together, and not function when the critical moment comes along. That means another adjustment.

Are you considering putting the chipper out front, and use the mmm PTO? Makes some sense to me.

 

[arrabil]

Based on the picture BHD posted I was thinking I could tack the bolts so they didn't get tightened. But I see what you mean about the clutches sticking. Just experienced that in my offroader #@!$&%$!.

I'm definitely going to add a shear bolt either way so it'll be double protected. I figure if a 3/8" bolt is good enough for the snowblower, I can start with a 1/4" one for the chipper and see how it goes. Always easier to make the hole bigger later if needed.

Are you considering putting the chipper out front, and use the mmm PTO? Makes some sense to me.

I looked at it some and I don't know that I like that idea any more. I would have to remove the loader to run the chipper. And I'd have to add the whole front PTO hitch. The chipper has to be attached to something, its not heavy enough to just sit on the ground. If it got stuck, the driveshaft would almost certainly be able to flip it around. I don't like leaving the front hitch on because I lose ground clearance so using the chipper would become an ordeal. Hmm.

What if I used two right angle gearboxes and ran the shaft from the mid-PTO under the tractor back to the 3pt!?!?