Grapple saw

[Conor Wright]

Is the 6 way valve plumbed off a proportional control, joystick or button activated auxiliary flow in the cab? 

 

What bar/pressure is the saw rated for and what bar does the digger put out?

 

 

[Richard Watts]

Good question the six way is plumbed off the auxiliary from the loader

the loader has 3 spool valve levers.

lift/crowd

aux 1 - grab/saw blade

aux 2 - rotate/blade raise and lower

i don’t know the bar rating should be around 150, I have ordered a pressure gauge and fittings to test it.

[monkeybusiness]

On 20/09/2021 at 10:18, Richard Watts said:

So I have a rotator on a log grapple. Attached to a small jcb.

I have fitted a grapple saw, 2 , 6 way hydraulic diverters

so the grab works, the rotator works, the saw (cut master basic) 9.4kw motor 64cm sword works

the ram that pushes the sword down is too quick I have put two restrictor 1mm holes each side still too fast

i have tried a diverter from one side to other with a tap between to divert some of the flow but either doesn’t work or too fast. Does anyone know how to set these up. Thanks 

Have you tried it in timber, or is it just too fast cutting with no load? Does the saw stall in timber? I’d imagine that ram should have a prv to allow it to keep a constant pressure on the bar without stalling the chain - the speed of the bar closing is almost irrelevant as it will slow when it pushes against the timber. 

[Arboraeration]

Its sort of hard to see from your picture but usually the saw motor and the ram that pushes the bar out are linked. So you would usually have a flow and return and case drain going into the saw motor and ram unit. Certainly this is the case on the intermacarto tiger cuts and the mecanil grapple saws I have been involved with. 

 

A tap is all or nothing, you will need something like this from memory. 

 

"Hydraulic 3 Way Flow Control Valve With Excess To Tank, RFP3 3/8 | Flow Control & Flow Divider Valves | Hydraulic Valves"

WWW.FLOWFITONLINE.COM

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"Hydraulic 3 Way Flow Control Valve With Excess To Tank, RFP3 3/8 from our range of Flow Control & Flow Divider Valves...

The 3rd port on this takes the excess flow back to the tank, this could be fed into the return line but probably better to go back to tank if possible. 

 

I have a feeling that I also had a larger diameter return like from the saw motor than feed. 

 

For longevity of the saw motor you will also want a case drain that returns freely to tank

 

[Richard Watts]

Thanks,

should I fit a pressure relief valve or diverter valve.

[monkeybusiness]

On 22/09/2021 at 07:44, Richard Watts said:

Thanks,

should I fit a pressure relief valve or diverter valve.

My reference to the prv was the assumption that there is one factory-fitted to the unit, which would allow the saw’s progress through the cut to be moderated to not stall the saw/damage the bar etc.
What actually happens if you try to cut timber? 

[Richard Watts]

It cuts but I need to be very careful with the control.

interesting cutting up larch off cuts from a mill is quite tricky.

yesterday I went into a fallen oak tree and chopped that up a treat, probably 4-5 cube in half an hour. I played with some 400 mm ash cut it easy. I would like the saw arm to be more controllable. I see on the website I bought the saw from there is a pressure relief valve as an extra, I have ordered on.

the original question was really should I fit relief or flow diverter 

I will let you know how I get on

[Arboraeration]

You will need a PRV if the machine pressure is too high, you either need to compare the specs of both to work it out or test the machine using a pressure tester

 

If the flow is too much (thats what it sounds like) then you will need a flow reducing valve installed, you can the adjust this to suit 

 

 

[LGP Eddie]

Your saw bar feed should have an adjustable flow restriction valve, usually with a grub screw so you can lock it.

 

I’d junk the 1mm restriction idea and fit an adjustable valve into the ram feed out side, which you can then adjust according to the type of wood.

My GMT, and Mecanil never really need adjustments for type of wood, but my large Hultdins unit would required quite a bit of fine tuning on site.

 

With regards to Grapple Saws and their use plenty of stuff going on, but the basics are the Manufacturer will set the risk zone of the unit, and also say if you have Chain Shot risk or not.

 

Eddie.

 

[Richard Watts]

PRV fitted, excess to tank,

works a treat!