Stumpgrinder rate of return

[aspenarb]

20 hours ago, doobin said:

How much flow rate do you think a pickup PTO actually puts out?? Let alone running the hoses around. You'd better budget for a massive oil cooler on the pickup somewhere also.

 

Direct drive is the most efficient drive posible, and a petrol 30hp engine is so much cheaper than all the above.

 

We built a large grinder with a direct drive motor for a big excavator and it was uncontrollable because slewing was far too erratic, on a small machine using the offset slew I would have thought it entirely feasible and workable. There is an old Rayco in the corner of the yard that would make a good donor for the bits so I may get in the workshop and cobble one together for our small Kubota. Thinking third service to operate a clutch.

 

Bob

[Will C]

@aspenarb

Would it work the other way on,  I’m thinking using the bucket ram to move the grinder whilst in work to make it more controlled 

[s o c]

On 26/12/2021 at 09:37, Dan Maynard said:

On 26/12/2021 at 09:30, doobin said:

A beaver pack won’t run any reasonable size stump grinder. Your biggest beaver pack is a 13hp petrol engine. The basic pedestrian machines are all 13hp, with no hydraulic losses. 
 
 I’m going down the route you suggest, but with an auxiliary petrol engine on the head- it’s the only feasible way. 30hp loncin should do nicely!

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I'm sure I've seen a picture of such a machine on here from a while ago? Think may have been an early Greenmech machine but might be making that up.

You are correct, there used to be a greenmech badged one.

Klou make one, or there’s one shown on there website.

(when I asked their rep at last APF ,he didn’t seem to know anything about it)

[Ty Korrigan]

In the opinion of those with more experience of these things, are grinders which use hydraulic motors instead of belts worthwhile or is the power loss to significant with smaller engines?

I've read articles that suggest 'up to' 30% loss overall.

   Stuart

[josharb87]

belt drive upto 35(ish) HP then the benefits of hyd drive take over

 

The wee tracked hyd drive vermeer for example is woefully underpowered, yet the wheeled belt driven vermeer with the same motor is a great all rounder. 

[Ty Korrigan]

6 hours ago, josharb87 said:

belt drive upto 35(ish) HP then the benefits of hyd drive take over

 

The wee tracked hyd drive vermeer for example is woefully underpowered, yet the wheeled belt driven vermeer with the same motor is a great all rounder. 

I used that Vermeer hydro machine whilst working for @pie eater pete

It seemed well made but so gutless for it's size I assumed it was faulty.

.  Stuart

 

[Mark Bolam]

My mate has the Predator 460 Stu, and gets on very well with it.

You still have to do a bit of manual work, which I know you’re used to, but it’s only swivelling.

It seems a very capable machine, and he’s done some biggish nasty stumps with it.

[mrstumpy]

On 28/12/2021 at 12:31, Ty Korrigan said:

In the opinion of those with more experience of these things, are grinders which use hydraulic motors instead of belts worthwhile or is the power loss to significant with smaller engines?

I've read articles that suggest 'up to' 30% loss overall.

   Stuart

You are correct hydro looses at least 30% of the power.  Direct drive loses around 10%.
I would consider 30hp at the cutting wheel a good entry level machine (upwards of a 45hp engine if the cutter is hydraulic motor driven).

[Ty Korrigan]

Aside from the Vermeer hydro tracked machine which is pretty gutless, there is the Toro STX 38

Anyone have experience of this machine?

  Stuart

Edited December 30, 2021 by Ty Korrigan

[mrstumpy]

20 hours ago, Ty Korrigan said:

Aside from the Vermeer hydro tracked machine which is pretty gutless, there is the Toro STX 38

Anyone have experience of this machine?

  Stuart

All of the small hydro machines are pretty underpowered.   The Toro  are a built to a good standard, (non-operator) issues are usually electrical or hyraulic.  Parts are fairly standard so can be purchased away from dealer.  
I do think you would be happier with something like a Rg37, Vermeer or Predator.
I keep forgetting the FSI D30, I would probably opt for this if I were in France.

Edited December 31, 2021 by mrstumpy
I missed FSI D30