Grapple Grapple needs flow restrictor?!

jinman · Oct 11, 2005

I used 1/4" hoses and a single 0.030 orifice I got from my New Holland dealer for $4.95. All the oil has to go thru the single orifice. It just changes direction, so all you need is one orifice. I put it between one quick-connect fitting and the hose fitting. I have absolutely terrific feather control of my single cylinder grapple. If it were two cylinders, I'm sure I'd have even better control. I bet I could pick up a sheet of paper without even poking a hole in it. /forums/images/graemlins/grin.gif

One caution I got from Mark at Carter & Carter was that on systems where there is a lot of flow, over time the orifice will cause a jet of fluid that can penetrate the hose. He suggested using a 90° fitting between the orifice and the flexible rubber hose. I think that's good advice. There's no need to tempt fate with a possible hose failure if a simple fitting can protect the hose. /forums/images/graemlins/cool.gif

sixwarden9 · Oct 11, 2005

Well gentleman, I will take all of your advice under consideration. Its been a slow morining at the office, but I'm about to hits the streets so I will be out of computer touch for a while. I am going to try and track some restrictors down this evening and might get them on tonight. I will keep you posted.

A side note: I have been working on this grapple as time permitted for a couple of months. After RITA we went without power for 10 days and lost numerous trees, most of which were on my power lines. So the need to pick up trees is now more of a necessity than a luxury. Once again, thanks for the input.

BigDogues · Oct 11, 2005

( Do they sell restictors by flow rate or just hole diameter. )
Yes they do. Here is one example at Surplus Center I have no idea if the restriction would be enough for you needs. But for under 10 bucks it might be worth a try. I'm sure some futher looking around might turn up something similar with an even lower flow rate.

sixwarden9 · Oct 11, 2005

BigDogues,

Your post brought up one more question (I ask alot of questions).

Port size when talking about hydraulics, i.e., SAE 8. I have searched the web for something that will translate this for me. I am pretty sure SAE stands for Society of Automotive Engineers and in this context is used to desribe an industry standard size for the holes. How does this translate to inches, or am I way off base.

MadReferee · Oct 11, 2005

Here you go. Conversions for SAE to thread size.

SAE 4 = 7/16 - 20
SAE 5 = 1/2 - 20
SAE 6 = 9/16 - 18
SAE 8 = 3/4 - 16
SAE 10 = 7/8 - 14
SAE 12 = 1 1/16 - 12
SAE 14 = 1 3/16 - 12

sixwarden9 · Oct 11, 2005

I went by TSC and bought two 1/32" (.031) restrictors for my 3/8" line. I put one on at the piston end of the cylinder (where the piston comes out of the cylinder) and tried it out. I worked great. I only paid $4.00 each for them so I will keep one in reserve, unless there is good arguement for using both. If I continue to use only one, does it matter in terms of grip strength whether the restrictor is on the piston side or the (for lack of a better term) butt end.

He suggested using a 90° fitting between the orifice and the flexible rubber hose. 

I took your advice Jim and placed before a 90 degree fitting. I would like to use 1/4" hose, but can't find any long enough.

The one thing I did notice between last night and today was how much harder the pump is working to push the fluid through the pin hole. The engine lugs down a little when I activate the cylinder (about 200 rpms). It was not doing this before the restrictor. Short term I do not see this as a problem, but long term I see extra wear on my hydraulic pump.

BigDogues · Oct 11, 2005

Here is a handy chart to add to, ummm, I mean lessen the confusion. /forums/images/graemlins/grin.gif

jinman · Oct 12, 2005

( The one thing I did notice between last night and today was how much harder the pump is working to push the fluid through the pin hole. The engine lugs down a little when I activate the cylinder (about 200 rpms). It was not doing this before the restrictor. Short term I do not see this as a problem, but long term I see extra wear on my hydraulic pump.
)

In an open-center system, as soon as you start to move the control valve, the open-center closes off as the working port opens. This always causes loading of the hydraulic pump and shows up as lowered engine rpm. I don't think you have anything to worry about in regards to pump damage. The control valves are designed so you never get a complete hydraulic lock. There is always some flow as the valve goes from open-center to working port flow. The fluid surely gets warm, but you won't stay in that situation long enough to cause the fluid to overheat. I would just consider what you described as proof that the orifice is doing its job. The grapple will move to the desired location in a short time and then when you center the control valve, the pump will go back to its free flow condition. In my opinion, the pump will not be in any danger of damage whatsoever. /forums/images/graemlins/cool.gif

sixwarden9 · Oct 13, 2005

Thanks for all the help gentleman. I removed a tree off of a shed and a fence last night. What a time saver. I decided to start saving my pennies for a valve kit, probably from W.R. Long. When I get my grapple painted and the valve kit I will post a couple of pics of me cutting trees down with my tree cutter and moving them to the burn pile with the grapple.

Matthew