upgrading a Farma 51-D grapple

OneWithWood · February 04, 2008, 01:52:46 PM

The 51-D grapple is a good grapple for small and medium size wood. Unfortunately a lot of the logs I wish to load weigh more than this grapple can handle. Forget the rated for specs - those specs are not reality :

I routinely need to pick up oak, hickory, maple 24+", 12 foot logs. The poor 51D can barely scoot these logs along. Occasionally I can lift one end on the trailer and scootch up the other end, but I have great dificulty placing the logs on a pile or getting them off the trailer in a controlled manner.

Research on the web has been erratic. A google search for "Farma 51-D" turned up a couple sites in a language I don't understand and a link to the Iron Inventory thread at the good old FF

What I am looking for is information on swapping out the hydraulic cylinders to get greater lifting capacity. Buying a larger grapple is not in the cards at the moment.

What information do I need to be able to intelligently proceed?

jackpine · February 04, 2008, 02:05:31 PM

OWW
A couple of things come to mind. If you go to a larger cylinder the overall length closed will get longer meaning you will not be able to open the grapple as far unless you can re-position the rear mounting. Also the larger cylinder will put that much more stress on the whole grapple, esp. the pins, and can possibly lead to premature failure.

Bill

beenthere · February 04, 2008, 03:39:34 PM

OWW
What cylinders are on their now...bore diam, stroke length, rod diam ?

What psi hyd pressure do you have? Hose size going to the cylinders?

Maybe we can figure something out.... :

Reddog · February 04, 2008, 05:43:46 PM

Quote from: beenthere on February 04, 2008, 03:39:34 PM
What psi hyd pressure do you have?

That is the first thing you need to know. Are you running at the max pressure?

Corley5 · February 04, 2008, 05:53:21 PM

Increasing lifting power may cause failure of other components. Proceed with caution.

Burlkraft · February 04, 2008, 06:32:03 PM

Quote from: Corley5 on February 04, 2008, 05:53:21 PM
Increasing lifting power may cause failure of other components. Proceed with caution.

You been readin' the instructions again ??? ??? ??? :D :D :D

Corley5 · February 04, 2008, 06:35:14 PM

;) :D ;D

leweee · February 04, 2008, 08:13:47 PM

Quote from: OneWithWood on February 04, 2008, 01:52:46 PM
What I am looking for is information on swapping out the hydraulic cylinders to get greater lifting capacity. Buying a larger grapple is not in the cards at the moment.

If you bend this one up ,it would be a good excuse to get another. ;D ;)

Stephen Alford · February 05, 2008, 08:17:04 AM

Hey OWW ; my experience with trying to beef em up resulted in identifing one weak link after another. I have never owned or been around a farma but I am curious if it has ever voided on you when it went past max lift capacity at any point from the mast? Stephen ???

OneWithWood · February 05, 2008, 08:57:59 AM

How do I determine the psi hydro pressure without cutting one of the lines?

The pressure could be a factor. I noticed that the spring wrapped around the governor rod (I think it is the governor rod) has broken. The engine surges at full throttle so I may not be getting max pressure. I will replace the spring and see what happens.

Stephen,
Please define 'voided'. If you mean has the boom lost pressure and decended prematurely while the valve is open, the answer is yes.

Gary_C · February 05, 2008, 09:12:06 AM

I do not know about that particular grapple, but the larger ones I use have a relief valve in the lift cylinder that is supposed to be set at some max pressure to keep from bending something or tipping something over. Sometimes with heavy logs in the grapple, you must pull them in close to lift and even then sometimes you cannot lift them. And if you do lift them when close when you try to move them away, the boom will drop as the pressure reaches max allowed in the lift cylinder.

Be very careful about raising that lifting capacity as it is usually set by the manufacturers tests.

Stephen Alford · February 05, 2008, 12:18:48 PM

Hey OWW; exactly as Gary has explained so well. It was not something that occured with the ol prentice G's. You could hear the pump and know you had reached the limit.However when you mentioned 24"+ ,12' maple that is substancial lift for smaller loaders. I had one smash through the leavers and snap the seat off and if had not been for the Bugs Bunny high diving act it could have been worse. I now have a guard in front of the levers as a precaution and the larger stuff goes on the bottom.The thing is a stick that size will hit all the levers at once and stuff happens. Just wanted to mention the danger. :

Stephen.