Kubota MX4800 3rd function - roll my own - check my work

Michael In Tennessee · Dec 2, 2018

Brian, I assume you have no issues with the work ports regardless of what size fittings I use.

/pine · Dec 2, 2018

FWIW...it can be worth consideration to save some money on hoses to use NPSM female pipe swivel fittings/adapters in place of more expensive JIC hose ends...

The swivel fittings come in all the same typical port thread/seal types (SAE etc.) with the angles etc on the fitting/adapters rather than the hose ends...they allow the use of all straight end NTP hose ends...they are a mechanical type 30* chamfer connection no sealant or thread compound required (same as JIC)
Makes measuring and ordering hoses a breeze...

MtnViewRanch · Dec 2, 2018

Michael In Tennessee said:
Brian, I assume you have no issues with the work ports regardless of what size fittings I use.

Correct, work ports will make no difference. Short term flow is of no consequence.

N2DFire · Dec 3, 2018

I'm asking out of pure curiosity (not because I'm trying to be an @$$ - which some would say is vastly out of character for me. LOL) because I'm sure Brian has dealt with more hydraulics this month than I have in a lifetime.

Why so much concern over the inner port diameter between -6 (3/8 or .375 inch) and -8 (1/2 or .500 inch) when the valve itself and the mating ports on the D03 subplate are 7.5 mm max (or .295 inch)?
https://www.sis.se/api/document/preview/603865/

My understanding is that (compared to the length of the entire system) the very short "length" of restriction while flowing through the subplate and valve body itself was considered negligible, if this is true then why not the same for the fittings? I also understand that in series ("stacking") of these reductions has a cumulative effect, but is it really that great?

I further confess I haven't looked at any charts, graphs, or calculations since I took fluid mechanics back in the '90's so I may be totally off base.

In my build, I used the D03 plate with NPT 06 connections and NPT fittings with swivels (BIG MISTAKE) but I had more room to work with. If I knew then what I know now I would have used NPT to JIC adapters in the subplate and JIC fittings on the hoses.

I did use 1/2" hose (with 3/8" fittings) for the lines on the P & T of the Subplate for constant flow and 3/8" hose & fittings for the intermittent flow work ports.

MtnViewRanch · Dec 3, 2018

N2DFire said:
I'm asking out of pure curiosity (not because I'm trying to be an @$$ - which some would say is vastly out of character for me. LOL) because I'm sure Brian has dealt with more hydraulics this month than I have in a lifetime.

Why so much concern over the inner port diameter between -6 (3/8 or .375 inch) and -8 (1/2 or .500 inch) when the valve itself and the mating ports on the D03 subplate are 7.5 mm max (or .295 inch)?
https://www.sis.se/api/document/preview/603865/

My understanding is that (compared to the length of the entire system) the very short "length" of restriction while flowing through the subplate and valve body itself was considered negligible, if this is true then why not the same for the fittings? I also understand that in series ("stacking") of these reductions has a cumulative effect, but is it really that great?

I further confess I haven't looked at any charts, graphs, or calculations since I took fluid mechanics back in the '90's so I may be totally off base.

In my build, I used the D03 plate with NPT 06 connections and NPT fittings with swivels (BIG MISTAKE) but I had more room to work with. If I knew then what I know now I would have used NPT to JIC adapters in the subplate and JIC fittings on the hoses.

I did use 1/2" hose (with 3/8" fittings) for the lines on the P & T of the Subplate for constant flow and 3/8" hose & fittings for the intermittent flow work ports.

As far as the DO3, plate, I think that I mentioned something about drilling the ports out also?

Here is another option, not recommended, but I have done it with no issues. Take the sub plate that you want to use and the -6 fittings and simply drill them out to -8 ID sizing.

I suppose that it wouldn't make much difference if you were a person that didn't use much more than 1/2 throttle most of the time. What I do know is that I have seen a 16GPM aux valve burn up a 17GPM pump. I had a customer that burned up 3 pumps on an MX5100, which turned out to be a flaw in the internal plumbing of the tractor's main case.

These failures ended up costing a lot of money and time for something that should have been easily avoidable if the proper parts would have been used.

If you are a person that uses their equipment pretty much to max more than half of the time, these small under sizings can make the difference between longevity and equipment failure.

Just my :2cents:

LD1 · Dec 3, 2018

/pine said:
FWIW...it can be worth consideration to save some money on hoses to use NPSM female pipe swivel fittings/adapters in place of more expensive JIC hose ends...

The swivel fittings come in all the same typical port thread/seal types (SAE etc.) with the angles etc on the fitting/adapters rather than the hose ends...they allow the use of all straight end NTP hose ends...they are a mechanical type 30* chamfer connection no sealant or thread compound required (same as JIC)
Makes measuring and ordering hoses a breeze...

Why do you say the NPSM fittings are cheaper?

Everytime I have compared.... they are the same or a mere pennies different

LD1 · Dec 3, 2018

What is your definition of a "good" price?

Is $70 a "good" price?
AD3SPS8S DAMAN. ALUMINUM VALVE SUBPLATE. DAMAN AD3SPS8S. | Trausch Dynamics

Michael In Tennessee · Dec 3, 2018

LD1 said:
What is your definition of a "good" price?

Is $70 a "good" price?
AD3SPS8S DAMAN. ALUMINUM VALVE SUBPLATE. DAMAN AD3SPS8S. | Trausch Dynamics

+$20 shipping.

Surplus Center has the -6 ORB D03 subplate for $35. Shipping is basically buried in the larger order I need to place. I have lived my whole life optimizing prices. It is very hard to "just do it" when I buy stuff. Character fault, but that is me.

LD1 · Dec 3, 2018

Michael In Tennessee said:
+$20 shipping.

Surplus Center has the -6 ORB D03 subplate for $35. Shipping is basically buried in the larger order I need to place. I have lived my whole life optimizing prices. It is very hard to "just do it" when I buy stuff. Character fault, but that is me.

~$75 shipped is about the best I can find delivered. AD3SPS8S - D3 Subplates - Daman | Hydradyne LLC

I am frugal too and always looking to optimize my dollar. If you cannot make NPT work with adapters and a JIC swivel (which will add to your $35 subplate)......then Im at a loss.

At some point.....it just isnt worth the time/effort to squeeze the last few pennies out of a build.

Have you looked into other options? Cartridge valve? Diverter? D05?

Michael In Tennessee · Dec 3, 2018

LD1 said:
~$75 shipped is about the best I can find delivered. AD3SPS8S - D3 Subplates - Daman | Hydradyne LLC

I am frugal too and always looking to optimize my dollar. If you cannot make NPT work with adapters and a JIC swivel (which will add to your $35 subplate)......then Im at a loss.

At some point.....it just isnt worth the time/effort to squeeze the last few pennies out of a build.

Have you looked into other options? Cartridge valve? Diverter? D05?

Analysis Paralysis. Part of my nature.

I can use NPT, just don't like 'em. I think I found a rear port D03 subplate in NPT. That eliminates lots of elbows and makes things neat and tidy. I'd just have to suck up my aversion to NPT. I'll have to go out to the tractor and see if hose routing works. The bracket would be a tad more difficult to make since it involves drilling big holes in steel plate. Should be able to use a bi-metal hole saw though.

I have some travel coming up for the holidays, so I won't start in earnest until first week of Jan. I can't guarantee I'll be home for part deliveries.