Brush hog hyd motor

[KentT]

Thanks Kent for the long note.

The turf tires on my PT seem to float over my good lawn areas without damage. If I fill them would I loose that advantage?

Your rear box is a great idea. However, the rear of my PT is vented, see photo, probably to provide extra cooling. Is yours vented? I would think that the box could be held back 4" to not block the vents.

Patrick

I don't think you'd see any more turf damage by simply loading the tires. But, it will likely ride a little harder, since the fluids will not compress under pressure, whereas the air will. You only fill them with fluid up to the base of the valve stem (with the stem at the top of the wheel), so there's still some air in them to soften the ride, but not nearly as much.

IF you're seeing turf damage from spinning tires, it may actually decrease the overall damage, since loading the tires would tend to reduce wheel spinning. Putting the additional weight in the tire, in contact with the ground instead of hanging the weight on the frame, doesn't increase the stress on wheel motor bearings and shafts as much as adding it to a weight box...

The rear of my tub is vented also, so this weight box does block those vents. My Kohler is located near the rear of the tub, but has pumps on both ends of the engine (PT used different layout configurations), just like the pictures on Moss's site. Mine is only a few months different in age from his.) I haven't noticed any overheating or negative effects, but I don't use that weight box all the time. Even tucked up tight to the PT tub, it will still hit the ground when driving out of ditches, down off steep inclines, etc. Unless you have a flat lot, moving it back even further could be an issue on what''s called "exit angle" by the off-roaders...

 

[Clumber]

Thanks for the great info. I think that I will fill the tires first to see if I can pop up small saplings without wheel spin. Eventually the rear weight/chain box will be another project. So many projects, so little time.

 

[MossRoad]

Do you have the pallet forks? I use them all the time to pop out small saplings. Just be careful, as the hydraulics are strong enough to bend them if you push it.

 

[J_J]

Just make one of these in a smaller scale.

 

[Clumber]

Do you have the pallet forks? I use them all the time to pop out small saplings. Just be careful, as the hydraulics are strong enough to bend them if you push it.

Yes I have forks and will try them. However, I would think my utility grapple (not the bucket) would work better. I will try again this weekend.

 

[nealfris]

One of the PT owners built a hyd powered 28 in ditch mower using a snapper deck. If the logic were to power it using the normal deck rpm, that would be around 3600. After working out the figures, using 8 GPM, and a .5 cu in hyd motor, the shaft rpm would be around 3696, and the torque would be around 199 in lbs. If you wanted more torque, then you double the cu in displacement to 1. cu in, then the shaft speed would be 1848 rpm, and torque would be 398 in lbs.

A 28 in blade turning at 3600 rpm will have a very fast blade tip speed. It will take about 14 HP to produce the 8 GPM's using a .5 cu in hyd pump. So if you translate that to the hyd motor, at 85% efficiency, the hyd motor should be putting out about 11.9 HP. So 11.9 HP, a .5 cu in hyd motor, and a 28 in blade, is a good combination.

JJ, I was wondering about the above equation for the snapper deck with 28" blade. I've been requesting help on my boom mower project which also has a 28" blade.
The advice was to go with a 11.4 pto pump and 3 cu in hyd motor. I was wondering what the difference is between the two scenarios? Is my 6.9 available GPM that much different than 8 GPM?
My tractor is 30 hp and it was suggested I would have 14 hp available to provide to the hyd motor. Obviously if I could add remotes off loader valve it would be $1200. cheaper that creating a pto pump system.
I'm not sure how to paste a link to another thread. Below is the title.

Default "Adding two hyd remotes to Kubota" 2/?/11

Thanks, Neal

 

[Clumber]

Just make one of these in a smaller scale.

Thanks, I had my eye on these for a while. Just need some time to talk to a local fab shop about what it would cost. Ideally, I would put a sharp edge with serrations to cut thru roots. That scoop plus more weight on the PT425 may give me the ability to remove 2-three inch saplings without leaving stubs behind. Filling the holes is easy.

 

[MossRoad]

Yes I have forks and will try them. However, I would think my utility grapple (not the bucket) would work better. I will try again this weekend.

I'd be more leery of bending that utility grapple prying on things than bending the forks prying on things. If it were me, I'd pop 'em with the forks and then go back and clean up the mess with the grapple. That's the beauty of the quick attach. It really is quick! :thumbsup:

 

[J_J]

JJ, I was wondering about the above equation for the snapper deck with 28" blade. I've been requesting help on my boom mower project which also has a 28" blade.
The advice was to go with a 11.4 pto pump and 3 cu in hyd motor. I was wondering what the difference is between the two scenarios? Is my 6.9 available GPM that much different than 8 GPM?
My tractor is 30 hp and it was suggested I would have 14 hp available to provide to the hyd motor. Obviously if I could add remotes off loader valve it would be $1200. cheaper that creating a pto pump system.
I'm not sure how to paste a link to another thread. Below is the title.

Default "Adding two hyd remotes to Kubota" 2/?/11

Thanks, Neal

nealfris,

If all you have is 6.9 GPM's, then if you use a .5 cu in hyd motor, then the shaft rpm would be 3188. Your torque will be lower, at about 199 in lbs. I am assuming 2500 psi. Blade tip velocity would be 23,431 ft per min, or 266 mph

If you use a 1.0 cu in hyd motor, then the shaft rpm will be 1594, and torque 398 in lbs. Blade tip speed of 11,955 ft per min, or 135 mph.

I believe you have 27.5 HP at the PTO on that L3000, so you could work out out how large an aux pump you could run any hyd implement.

Where does the $1200 come from? Maybe if you get the most expensive stuff they have. If you add an aux motor spool valve, and hoses, to the boom mower hyd motor, plus steel and cyl.

 

[nealfris]

I was guesstimating cost of pump, tank, filter and housing, fluid, hoses etc. for the whole system. Maybe less than $1200 but a sizable amount. The pump is $500 plus shipping alone.
I know you've help me on the previous threads and I appreciate all your help. I just can't decide which way to go!
So my thinking was; try the remotes. I will need motor spool, all the hoses, fittings etc. for the mower regardless. I'm going to add remotes anyway. But I guess the rub is the motor.
With the input on the pto pump idea, the design suggestion is 14.4 GPM pump, 3 cu in motor and 1 in. hose. Whereas the remotes idea would give me a whole different motor requirement. I am still not sure about the heat build up.
Not sure how to go. Like some tractor attachments, you use the h*ll out of them for a short spell and then use them once in a while. This may fit that category for me.