Grandson has been pricing specialty mowers for mowing orchards and ditches and such. Lots of suitable technology out there, but the prices will take your breath away.



I'm thinking of building a hydraulic version of my diesel string trimmer. The idea is that the string head would be hinged so it could tilt up/down. It would involve a PTO mounted pump to run a hydraulic motor on the string head. What I need to know is whether or not my combination of components is suitable. I'm looking for 3-5 HP at the string head. RPM can be achieved by suitable pully ratios if needed.

Here are my first thoughts:

PTO Pump - Surplus Center 9-8902-3, 7.4 GPM @ 540 RPM
Motor - Surplus Center 9-16442-12, 5.2 GPM @ 1500 PSI
Tank - Surplus Center 9-8416-5, 5 gallon capacity

Insights/Suggestions appreciated.

I’m not an expert, but I do have a JD 3046R with a bunch of attachments.

If it is a closed system, do you really need 5 gallons of reserve fluid? My PTO driven wood splitter converts PTO to hydro and probably only has a few quarts in reserve. Once the pump and lines are filled, where is it going to go?

quote:

Originally posted by MNSIG:
I’m not an expert, but I do have a JD 3046R with a bunch of attachments.

If it is a closed system, do you really need 5 gallons of reserve fluid? My PTO driven wood splitter converts PTO to hydro and probably only has a few quarts in reserve. Once the pump and lines are filled, where is it going to go?

It's mostly about cooling. The motor will run continuously and generate quite a bit of heat.

quote:

Originally posted by PHPaul:
It's mostly about cooling. The motor will run continuously and generate quite a bit of heat.

That makes perfect sense. Chippers and splitters are much more intermittent than a mowing attachment.

You are correct that heat will be an issue. You may not need 5 gallons if you put an intercooler in the line, but it may be simpler to simply keep cool with volume.

I also don't know if for an application like that "frothing" could be an issue.

Dad made a hydraulic saw that he worked off his truck, but had a 5gal recovery sump to cool the oil before it went back into the pump, so just a large volume of oil to keep the hoses cool.