425 Hydraulic Spec's ? - Found a Trimmer

[DaveS]

425 Hydraulic Spec\'s ? - Found a Trimmer

Found a hydraulically driven 38" sickle bar trimmer for use with my future 425 at Sabre Crop Divider This unit sells for about $750 US. It requires 3.3gpm at 500psi or less. Could someone please tell me the 425's gpm and psi ratings? I suspect to achieve less than 500psi a pressure reducer might be required?
FarmShow had a photo of one of these mounted on the side of a loader for trimming back brush. Just what I need.

Thanks, Dave

 

[Rip]

Re: 425 Hydraulic Spec\'s ? - Found a Trimmer

Dave,

Allow me to welcome you to the forum... sharing questions & answers, woes and successes and experiences of all kinds are what it is all about.

The 425 PTO circuit is rated at 8 GPM @ 2500 PSI so you would have plenty of capacity available for the Sabre sickle bar you mentioned (looks nice by the way).

My advice to any PT owner is to find and become aquainted with a good local hydraulic shop or mechanic. Depending on your abilities, time, and inclination you can pay him for repairs or modifications, or get him to walk you through doing them yourself. In any case, unless you are already a hyd tech or enjoy learning everything the hard way, establishing such a relationship will smooth out your life with a PT. This forum will be a big help in any case though.

That said, I am sure that a few simple yet well chosen componants will readily adapt the sickle bar (and other potential attachments) to your 425 very successfully.

I know there are others here who would welcome a good idea to "borrow" if you end up building something and can document the process as well as the finished product. PT has a knuckle boom mower attachment for the 1430 and larger machines that you may be able to get some ideas from.

Good Luck, Rip

 

[Schultz]

Re: 425 Hydraulic Spec\'s ? - Found a Trimmer

You have a number of options, none are no brainiers.

You could put a motor flow control valve, but the excess has to be plumed back to the tank or a return line. Or a flow divider and a flow combiner in (lots of $). Or change the motor to one that matches your flow and rpm requirements, this probably being the easiest. Any of the systems will require a pressure relief valve otherwise the sicke bar could self-distruct if something jams it.

 

[DaveS]

Re: 425 Hydraulic Spec\'s ? - Found a Trimmer

Thanks guys for the good information. I guess I need a little more clarification on how the hydraulic "power beyond" works. If I understand it right, the same circuit and controls used for the quick-attach clamping system are what operate the motors on attached devices, i.e. mower motors. I thought after the quick-attached clamps are clamped, then the hose quick-disconnects are disconnected and hooked to the implement motor, then the lever under the dash is used to turn off or on the implement motor. Is this correct? If so, I'm assuming there is a pressure relief valve in the system to relieve pressure when the quick-attach clamps hit their stops. The web-site for the Sabre sickle cutter says no flow control or divider required. Sounds like I need to contact them for more clarification. Thanks again for the input.

 

[Bob999]

Re: 425 Hydraulic Spec\'s ? - Found a Trimmer

<font color="red"> If I understand it right, the same circuit and controls used for the quick-attach clamping system are what operate the motors on attached devices, i.e. mower motors. </font>

Normally an attachment with an hycraulic motor is connected to the PTO circuit, not the quickattach/steering circuit. On the 425 I believe the PTO circuit has an 8 gpm flow and that is the basis for the need for protective devices.

 

[Rip]

Re: 425 Hydraulic Spec\'s ? - Found a Trimmer

Not quite correct... The PTO circuit is separate from the lift and QA circuits.

The PTO is controlled via an on/off dash switch controlling a solenoid valve. It is unidirectional and is used only for attachments that utilize a hydraulic motor. It produces the rated pressure at any engine speed above fast idle, but rated flow requires near or full max rated engine speed.

There is a pressure relief valve in the PTO circuit, but constant use at a restricted flow should be handled in a different manner. The motor for a sickle bar would only need to be operated in one direction, so no bidirectional control would have to be added.

The three-spool valve with the joystick control for lift and curl plus the small lever under the dash is for cylinder operation only, and each valve circuit is bidirectional. While I am not sure if the valve body on the 425 has a "power beyond" port, there are several ways additional cylinders can be operated.

None of this would be a challange for a hydraulic technician, but neither is it a DIY project without some expert guidance that is probably beyond what you are likely to get on the internet.

Thus my earilier suggestion to make your acquaintance with a good local hydraulic shop or mechanic and benifit from his expertise. The key is the proper layout and componants.... the actual connecting the hoses is simple and something you can probably do and save the labor cost.

What you want to do is quite "doable", but it can be done right the first time or one can spend a lot of time and money and end up with a kludge that never works right. Farm Show has many good examples of both.

Good Luck, Rip

 

[DaveS]

Re: 425 Hydraulic Spec\'s ? - Found a Trimmer

Thanks again guys for the good input. Obviously, I didn't understand the circuits correctly (and if I'd thought about the pictures of the of the 425's dash, with a PTO switch, I probably could have figured it out). Again, thanks for the clarification, I now understand the alternative use for the Q-A circuit, and the use of the PTO circuit. Rip, you're exactly right about getting help with the hydraulics. I have a friend who is in the business and sells components to OEM's and repair shops, so I'm sure he can help. But since I don't have either the PT or trimmer head yet I wanted to see if the application was feasible, and be able to ask intelligent questions to my friend. And you're also right that the fabrication and wrenching portions of the project are well within my abilies, AFTER getting good advice from you guys and a local pro. Thanks.

Dave