3/8" or 1/2" hose for rear cylinder?

[sixdogs]

There has been this discussion before since I have seen it but can't find it now in a search. I am rebuilding a simple drag harrow that needs a typical 3" by 8" cylinder for the lift function. In the past I have always used 1/2" hose because that's what I have always done before. The plan now is to use this with my Kubota L4300 that came with 3/8" NPT hose ends. So I already have those plus I have some 3/8" hose on hand that would work. I would simply use a 1/2' by 3/8' 90 degree adapter on the cylinder ends. If I used the 3/8" I would save around $50. I would primarily use my L4300 with this there may be a time when I use the cylinder on different equipment or a bigger tractor.

As I recall, smaller or larger hose has an impact on the cylinder behavior but I cannot recall exactly what that was. Any help on this?

 

[RickB]

For that application it won't matter enough to make any difference. Use what you have, or whatever size you can make the connections for the easiest.

 

[Bigfoot62]

. . .
As I recall, smaller or larger hose has an impact on the cylinder behavior but I cannot recall exactly what that was. Any help on this?

The larger the hose, the more volume of fluid, the faster the cylinder can cycle - Up to the capacity of the pump.

As Rick pointed out, I'm not sure that you could tell much difference on this application. If the TractorData info is correct, your tractor has a valve flow rate of 7.8gpm.

 

[SPYDERLK]

If I used the 3/8" I would save around $50. I would primarily use my L4300 with this there may be a time when I use the cylinder on different equipment or a bigger tractor.

As I recall, smaller or larger hose has an impact on the cylinder behavior but I cannot recall exactly what that was. Any help on this?

Use what you have and save money. ... For that you will lose nothing in that application because the speed of movement of your cylinder is not critical. Small or very long hoses will reduce the top speed of cylinder motion [especially]with systems that have hi delivery pumps. This is because the pressure needed to drive the same fluid thru a smaller or longer hose is greater ... and with the higher GPM may indeed be great enuf to cause the pressure relief valve to operate. This would vent [essentially divert] some of the potential cylinder flow to the reservoir. Makes it less critical that you operate your control valve with great finesse. - Often you may find it convenient as well as economical to use 1/4" hose in such applications. They have side benefits of easy routing due to their suppleness.
larry

 

[kennyd]

Anything bigger than 1/4" is a waste of money and real estate if you had to buy it, but since you have the 3/8" use it.

 

[brewdog]

Anything bigger than 1/4" is a waste of money and real estate if you had to buy it, but since you have the 3/8" use it.

I agree totally. I used 3/8" and wished I would of used 1/4" for my Top Link. The 3/8" hose was readily available at the time. The 1/4" is much more flexible and easier to route. Thinking about installing a needle valve to slow the cylinder down, its way to fast.

 

[IslandTractor]

Another vote for smaller hose. Anything that doesn't need to move very quickly does fine with 1/4 inch hose. My 4n1 bucket has 1/4 inch hose feeding the two cylinders. Topping lifts certainly don't need real high flow either. I would presume a drag harrow adjustment is occasional and not time critical. The difference in speed would probably be in the order of a second or two anyways.

 

[jinman]

One other issue is ballooning of the hoses. A good 1/4" hose will balloon less than 3/8" or 1/2". For short runs, you'll probably never see any difference, but for long runs it adds up. If you have 3/8" available, that would be my choice. You'll probably never notice much difference.

 

[MHarryE]

Hose manufacturers recommend 15 feet per minute fluid velocity at full flow rate for minimum pressure drop and minimum damage to the hose liner. 3/8" hose at your pump's max output is 22 gpm and that is okay. 1/2" is about 12 fpm, very good but larger than you really need. 1/4" hose puts the max flow rate at over 60 fpm which is bad for the hose. BTW Gates, one of the largest hose manufacturers in the world, shows 7 to 36 fpm as the recommended range for pressure hose and 2 to 4 fpm for suction lines. Slower velocities don't hurt but generally are a waste of money.

 

[sixdogs]

The data below is for my bigger Deere5520 tractor.
I presume no problem with this either with 3/8" hose?
I don't know what fpm is.


Type: open center

Capacity: 10 gal [37.9 L]

Pressure: 2800 psi [193.1 bar]

Valves: 2 to 3

Valve flow: 15.9 gpm [60.2 lpm]

Steering flow: 6.6 gpm [25.0 lpm]

Steering press.: 1900 psi [131.0 bar]