Check my logic, please

[NCMau]

Why are you looking at such low speed high gpm motors for?

They make about every possible rpm and flow motor there is.

Your tractor makes 7gpm.....say you want to dedicate 4 gpm to that. And you want 1500rpm....

Just select a pump that will produce 1500rpm at 4 gpm.

No point in buying a slow pump....and slowing it down even more by not delivering the flow.....just to step it back up via a 5:1 pulley. Which by the way....is an EXTREME step to do with a single belt. If your mower pullet is a mere 4" diameter.....that means you need a big honking 20" pulley on the motor.

Okay, clarification.... My original inquiry was about these two hydraulic motors that have and that I was hoping to use for this mower project. As I stated, I am not willing to change the loader PTO pump. If this project is not viable, then I’ll dump it and possibly consider an alternative.
Some time ago, I made a prototype using motor #1 for a 12” blade branch trimmer. This prototype was using a 3:1 pulley ratio (6” motor, 2” arbor). The speed was not fast enough.
I am tempted to try with a 10” or 12” pulley to give me a 5 or 6:1 ratio. If this would work, then I’ll find a gearbox for the purpose. I can use the same arbor setup for the mower deck. Just experimentation, no money involved.

 

[prichard]

If it was me, I'd just start building. Make it easy to swap between the 2 motors and see what happens. Like you said, low priority and free parts. What you have to lose ?

 

[LD1]

Buying pulleys, especially a good quality 10-12" one, isnt cheap. Then that's alot of upulley hanging on that motor shaft. And a 2" driver..... Hard on belts. Now add a larger driven pulley and you don't have alot of contact at the blade. I can see it eating belts.

For the time, effort, and money to try to make one of the motors you have work, I'd rather drop a few hundred on the right pump. Forget belts and pulleys

 

[NCMau]

Buying pulleys, especially a good quality 10-12" one, isnt cheap. Then that's alot of upulley hanging on that motor shaft. And a 2" driver..... Hard on belts. Now add a larger driven pulley and you don't have alot of contact at the blade. I can see it eating belts.

For the time, effort, and money to try to make one of the motors you have work, I'd rather drop a few hundred on the right pump. Forget belts and pulleys

I realize that what you are saying makes sense but I have the pulley on hand and I am going to give it a go.
But let’s say I go with a new pump, what would be a suitable GPM size for my 35 HP tractor? The tank size would be problematic for installation. The existing 10 gl. tank is comfortably mounted behind the seat. A bigger size tank I am not sure it will work… maybe.
I could go with a front mounted pump but then I have to run the hoses to the back. Would this be a viable approach?
Speaking of a front pump, I have one. It is never been used, but I have no idea what capacity or brand it is. I tried to make a comparison with Surplus Center pumps but I can not identify it. I will do another posting with pics and dimensions. Maybe some good souls will chime in.

 

[Coyote machine]

The reason why I don稚 want to change my loader PTO pump and tank is because this project is not exactly high priority. If it would work with what I got, fine, otherwise I can skip it. I do have other ways of accomplishing the task, like a modified walk-behind sickle bar mounted on the bucket. This bar, however is not suitable for any growth bigger than 1/2 at best. Also it is a PITA to mount. I was looking for something simpler.
I remember few years back reading one of your posting when you purchase your Samurai, and you were pretty happy with it. It痴 amazing that it does a good job running just with 3 GPM (if I remember correctly). Anyway it痴 a sweet machine, but man, it痴 not cheap.
Another alternative I could have without using hydraulics is to mount the deck with a horizontal electric-start gas engine... possibility.

I'm guessing from what you stated above about wanting to cut brush larger than 1/2 inch that you primary objective is to rig your mower to cut brush?
My Samuri sickle bar, hydraulically driven cutter is fine for some tall grasses and some live wood brush, BUT it is NOT fast with respect to how quickly it can cover an area. It's cutters move quickly on the bar but slow and steady is the pace over ground. Think low range of one's tractor. My problem with it is, even though I bought a QA plate to attach it to, the plate is not completely flat,
(especially near the bottom), so my welder guy could not mount the bracket that attaches to the cutter low enough that the FEL and QA plate won't dig into the ground when I'm trying to cut the grass on ditch banks. I'm going to have to rig it up differently to get it to work for what I need to use it for. Also, at times when cutting brush it will get a piece caught in between two knives and tend to jam up. I can usually get it to release without climbing off the tractor, but it makes for a frustrating experience.

Again, if you would state your main intent for the piece of equipment you are trying to make function I believe we could better advise you how to accomplish the task.

 

[NCMau]

I'm guessing from what you stated above about wanting to cut brush larger than 1/2 inch that you primary objective is to rig your mower to cut brush?
My Samuri sickle bar, hydraulically driven cutter is fine for some tall grasses and some live wood brush, BUT it is NOT fast with respect to how quickly it can cover an area. It's cutters move quickly on the bar but slow and steady is the pace over ground. Think low range of one's tractor. My problem with it is, even though I bought a QA plate to attach it to, the plate is not completely flat,
(especially near the bottom), so my welder guy could not mount the bracket that attaches to the cutter low enough that the FEL and QA plate won't dig into the ground when I'm trying to cut the grass on ditch banks. I'm going to have to rig it up differently to get it to work for what I need to use it for. Also, at times when cutting brush it will get a piece caught in between two knives and tend to jam up. I can usually get it to release without climbing off the tractor, but it makes for a frustrating experience.

Again, if you would state your main intent for the piece of equipment you are trying to make function I believe we could better advise you how to accomplish the task.

The purpose would be to keep about 3000 ft of wood trails (each) side trimmed. I can use my 36" sickle for the puny twigs but not for anything bigger than 1/2", and... sometimes those pesky twigs get stuck between knives, as you well know. This is why I thought a small side deck would be more ferocious. Sure it would cover smaller cutting areas, but in my situation it does not have to be a continuous trim.

 

[Coyote machine]

Why does your sickle only cut up to 1/2"?
Can we get a pic of it?
Mine cuts up to 1/1/2"....

 

[NCMau]

Why does your sickle only cut up to 1/2"?
Can we get a pic of it?
Mine cuts up to 1/1/2"....

Here it is. It was originally a walk-behind Gravely Sickle, later modified for the tractor. Operated by the loader 7 GPM PTO pump. It seems to have the right speed.
Using motor #1.