Want to build an 80 inch hydraulic tiller

[SpecElim]

Hi guys. First of all I am new and would like to introduce my self. I am Matt and I would like to build an 80 inch Hydraulic driven tiller as the title says. I want this to hook up to my category II 3pt hitch. I have a New Holland 3010s 65/55 pto horsepower tractor. I have 1 remote outlet @8 GPM. I have found some very basic plans online but would rather base my build on the Woods GTR72 reverse tine tiller. I would also like to use some chain driven parts from agri supply to keep repair as cheap as possible. I now need to figure out how to protect the Hydraulic motor from damage if the tiller hits something. This will be a very heavy tiller as I have to make it as heavy duty as possible. I am thinking about 1200-1500 pounds. Here are the very basic plans that I am basing my design on. LifeTrac - Open Source Ecology
Here is the tiller I would like to base it on but would be more difficult.
Woods Equipment Company - Reverse Rotation Tillers


If anyone could help I would appreciate it a whole lot! Thank you, Matt.

 

[J_J]

Welcome to TBN.

8 GPM does not represent very much HP to drive something as big as 80 in tiller. I would think about 48 in would be your limit, if that much. What is your psi rating on the tractor?

 

[Renze]

Your tractors oil pump doesnt have enough power to drive it. an 80 inch tiller uses 3/4 of the power of your tractor, and this 8 gpm pump will only be able to generate about 10 to 15 Kw, depending on the pressure available.

In most high power hydraulic applications on tractors, a PTO driven hydraulic pump is used... but if you go that route, why put away the existing PTO drive of the tiller ?

By the way, what benefits are you seeking to accomplish with hydro drive anyways ??

 

[J_J]

It takes about 14 HP to drive a pump at 8 GPM, at 2500 psi. So if you are driving a hydraulic motor, with an 85% efficiency, that puts your motor at 11.9 HP.

 

[J_J]

Why would you want a hydraulic tiller ? Your tractors oil pump doesnt have enough power to drive it. an 80 inch tiller uses 3/4 of the power of your tractor, and this 8 gpm pump will only be able to generate about 10 to 15 Kw, depending on the pressure available.

In most high power hydraulic applications on tractors, a PTO driven hydraulic pump is used... but if you go that route, why put away the existing PTO drive of the tiller ?

By the way, what benefits are you seeking to accomplish with hydro drive anyways ??

He might be wanting to do some reverse tilling. They make PTO reverse tine tillers, just select one that matches the PTO HP.

MY hydraulic tiller runs on 15 GPM, and it is 72 in.

 

[SpecElim]

I am just trying to build something that is about half the price of a heavy duty 80 inch tiller from an industry made one. I can get a 23 GPM pump for my pto for $500 from northern tool and still be cheaper at the end. A comparably sized tiller retails for about $2000-2400. Thanks for the quick replies.

 

[Renze]

MY hydraulic tiller runs on 15 GPM, and it is 72 in.

This would be enough to do a well kept garden which is tilled every year, but not "heavy duty" tilling as the OP describes... a 2.30 meter (90") Kuhn tiller takes about 60 hp at 10" depth when cutting horse pasture.

 

[Renze]

I am just trying to build something that is about half the price of a heavy duty 80 inch tiller from an industry made one. I can get a 23 GPM pump for my pto for $500 from northern tool and still be cheaper at the end. A comparably sized tiller retails for about $2000-2400. Thanks for the quick replies.

But why do you insist on hydraulic drive ?

 

[SpecElim]

I don't insist on hydraulic drive but so far it seems like the cheapest and easiest route.

 

[Renze]

I don't insist on hydraulic drive but so far it seems like the cheapest and easiest route.

As a basic rule of engineering, hydraulic drive is only cheaper if it requires continuously variable drive (hydraulics are easier to adjust, but only when you have variable displacement motors) or when hydraulic hoses are easier to route than multiple shafts, pulleys, gearboxes, chain drives. This all at the cost of a way lower efficiency.

So what you're trying to achieve, is to turn your existing Woods standard tiller into an overtop tiller ?

The easiest way to achieve that, is to open the gearbox and move (mirror) the position of the gearwheel of the transversed shaft, along the longitudinal shaft. Then remove ALL your tiller blades and begin reassembling them in reversed order (along the new direction of cut)
You do need to invert the rotational direction of the blades, because otherwise it would have a negative cutting angle or "bite" which means the blades act as ski's

 

[J_J]

Renze ,

He doesn't have a Woods tiller, he wants something similar. And yes they do make tiller blades that will cut/till in both directions.

 

[SpecElim]

Correct I do not have any tillers for a tractor I am trying to make one and it just seems cheaper and much more simple to work with a hydraulic pump and motor. If you guys insist that a pto gearbox/shafts can be as easy/cheap then I may go that route but my budget is about $1000 including steel. My estimate for a hydraulic pto pump and a 15 cu in motor is about $600 from northern tool.

 

[Renze]

My estimate for a hydraulic pto pump and a 15 cu in motor is about $600 from northern tool.

Ok, the cheapest hydraulic pump and motor might be cheap. But what about the hydraulic hoses ? cardan shaft ? steel ? tiller shaft main bearings ? With only that, you'll be over your budget.

I'd try to find something in the scrapyard. A good gearbox, chain and sprockets.
Preferrably a used tiller, because a full set of blades isnt cheap either.
Believe me, building machinery from scratch when a mass product is readily available, wont save you money when using new parts, you just might be able to break even. If you use used parts, and have access to the right tools and machinery (relations with people in welding shops) you might be able to save some money, but usually these projects run way over the budget... Believe me, i have too many of these

Just my advice: Buy a used piece of equipment to get a jumpstart with this inversed rotation tiller.. And think once again before you start chopping it up

 

[SpecElim]

You are correct. I am looking for scrap but my local scrap yard does not have anything for a tractor. They love to cut whatever they get right when it comes in. If you can convince me that I can build a pto driven one for about the same as a hydraulic one please go right ahead. I am working on a 3d model as we speak and will post it within the next hour. Thanks, Matt.

Quick change of plans. I am going to use a 1-1/8" x 76-1/2" square disk axle from agri supply as my main shaft. This way the replacement shafts/ bearings are very cheap. I can weld the tines straight to the shaft. when they need to be replaced I can cut them off and reweld new ones.

 

[Renze]

This way the replacement shafts/ bearings are very cheap. I can weld the tines straight to the shaft. when they need to be replaced I can cut them off and reweld new ones.

Have you thought about the balancing issue ?

 

[powerstroke444e]

A complete set of blades for my howard tiller cost around $500 last time I ordered them to the best of my memory. I will build about anything but 80"tiller heavy duty? You will have more time in getting the shaft and bearings put together than than its worth, never mind the cost of the steel.
Go find a used howard 60" and I bet it if you put it all the way down you can kill your 60+hp tractor. As I have put it on the back of a 4020 deere and made it cry for mercy. The Kubota M5400 does ok with it but only in low gear when grinding roads.

 

[SpecElim]

Here are some of my basic Drawings.

RapidShare: Easy Filehosting
RapidShare: Easy Filehosting

Thanks

 

[radman1]

My Bobcat 68" tiller is run at 19 gpm. I can easily stop it when tilling and not in tough conditions. The tiller is chain driven from the hydraulic motor. If I use my pto driven tiller on my Toolcat, I can use my hi flow hydraulics to run the pto (hydraulic motor) and that produces 28 gpm at 3000 psi. Again I can stop the rear mounted pto driven 72" tiller rather easily in moderate to hard conditions. My JD 3720 with 44 hp engine, can handle the rear pto driven 72" tiller much better in hard conditions and will make the slip clutch activate. If you want a HD hydraulic operated tiller, you will need much more flow than 28 gpm and probably need 40-50 gpm for 80" tiller. With that much flow, you will need an expensive pump, oil cooler, oil reservoir, big hydraulic hoses in the 1" size ect.
Forget the hydraulic approach for running the tiller, too much inefficiency with hydraulics unless you have lots of flow and/or pressure. This link may help you convert hydraulic flow/pressure to horsepower.

Hydraulic Motor Calculator
Baum Hydraulics Corp :: Spec Calculator

 

[kennyd]

Where are you located?

 

[joes_427_vette]

The $1600.00 King Kutter tiller is sounding cheaper by the post. I don't think one can build a 6' tiller any cheaper than the production models. Replacement parts may be an issue down the road as production items are available and one of runs from a surplus center may not. Of course everyone needs therapy... and this project would keep you busy for a long time. Good luck, keep us posted on the progress.