Finish Mower with Hydro adjust height

Exscriptor · Jun 4, 2012

Finally finished last winter's project. I have several acres to mow on my place plus others as well. I have never liked adjusting the cutting height as it take time and is a greasy mess trying to handle the axles and spacer washers. So, after much thought and planning, I built a proto-type out of wood, made some adjustments and then hit the shop with the steel, cut it up and had a friend weld it together for me. Worked, but not as it should. Did more research and had to replace the hydraulic flow dividers with different ones, and now all is well. I hook up the hydraulics to one of the remotes and can adjust the cutting height on the fly. I even made a simple guage on the right rear wheel so I know the height I am cutting at. Ton of fun to do. The mower is a KingKutter 72" that I picked up "well used". Disassembled it, stripped off the rust and old paint, replaced what parts were worn, repainted it to Mahindra colors. Has adjustable holes for the cylinders that change the minimum/maximum cutting heights; lowest is 1.5", max of 8".

Ductape · Jun 4, 2012

Freakin awesome ! :thumbsup:

catdozer · Jun 5, 2012

I second that, freaking awesome!! Just about How much did it cost?

Farmerford · Jun 5, 2012

Great job! I thought about the cylinder synchronization issue on a similar project (that I have not started yet). How did you solve the problem?

Exscriptor · Jun 8, 2012

The cylinders are synchronized by three cartridge type hydraulic flow divider/combiner valves. You need one to divide the oil flow to right and left side, and then one for the left side to divide the front and back, and likewise for the right side. The combiner part of the valve gives you metered flow in the reverse direction, so going up or down you get synchronization. You also need to prevent the oil from transferring back thru the divider valves, so you need a Locking valve, also called a pilot operated check valve, for each cylinder. With the cartridge type divider valves, accuracy is about 98%, so every 4 or 5 adjustments you should run the cylinders all the way out or in to get all in sync again. Rotary flow dividers are much more accurate, but the cost and other considerations would not be practicable for a project like this. The cost? About $1,600.00. Can do it for less with industry discounts. I did this project for the fun of designing and constructing it and to see if it could be done. It was great fun.
If anyone wants plans for this setup, I have them available. They are for any KingKutter mower with the 1.5" x 2.5" wheel mounting bracket channel welded to the deck. The wheel set can be used on almost any finish mower: only the mounting bracket peculiar to each brand of mower would have to be made to fit. The main advantage to this wheel design is that there is no modification to the mower, other than drilling a few holes to mount the divider valves onto the mower. These wheel assemblies simply fit into the existing wheel mounting channel and are held in place with the set bolt already on the mower.

Farmerford · Jun 8, 2012

Thanks for the reply. I wondered how well the restriction type flow dividers work in practice. On things like priority flow to power steering you can't really tell (and it doesn't really matter) if they are precise. Sounds like they work well enough for most purposes.

Again, that's an impressive project.

npalen · Jun 9, 2012

I agree, a very interesting and neat project.
Another way of synchronizing the four cylinders is using rephasing cylinders in series which is the way a lot of farm tillage equipment is done. The downside is that each cylinder in series (slave) has to be slightly smaller in bore size than it's master. This makes up for the difference between the rod side and the base side of the piston.

TraderMark · Jun 11, 2012

That's just too cool.
Now you have the wheels in my head a spinning!!

pilot-werx · Jun 17, 2012

Genius award winner right here!

evo803 · Jun 20, 2012

Why did you use individual hydraulics and not just one central hydraulic adjustment. If you connected the upper pivot point of each rear wheel from left to right with round bar and then did same in the front. You could then tie them together with a "toplink" or similar linkage wich would allow the use of one cylinder for adjustment.