Hd

[melvinhatcher]

Hydraulic pipe fittings versus water pipe fittings, are they interchangeable?

 

[4570Man]

Usually no because the water pipe isn’t rated for sufficient pressure.

 

[Tx Jim]

Ditto WP fittings are not rated for hyd pressures

 

[old and tired]

Would you use something rated at 600 to 800 psi in a system that runs 2500 to 3000 psi (spike pressure)?

Some of the low pressure return to tank, you might get away with it but the risk is not worth it...

 

[rScotty]

Hydraulic pipe fittings versus water pipe fittings, are they interchangeable?

Well.... interesting question. Many hydraulic and water pipe use the same threads, particularly the interference type like NPT. And on older US farm tractors you will see a lot of what sure look like water pipe fittings. The OEM fittings on our old John Deere model 60 loader - vintage 1950s - look to me like water pipe fittings. And they are what came that way from the factory.

Some things to think about: That loader went on JD tractors back when the standard hydraulic pressure in JD Ag tractors was 1100 to 1250 psi. Water pipe fittings are only rated to a max of half that, but good steel and quality USA manufacturing may have allowed them to get by at tractor pressures of the time. Or maybe they made a higher rated fitting back then.
You know that something must have worked OK, because because you can see old USA made water pipe fittings in use every day on vintage Ag at a thousand farms and at every tractor show.

But more modern tractors after about 1960 began to use higher pressure hydraulics. They quickly came up to today's pressure of 2500 to 3200 psi. At the same time, those quality steel water pipe fittings have disappeared and are replaced by imported fittings that are cheaper - partly because they are only made to meet basic water pressure specs. Much lower specs. I've had modern plumbing fittings split just from being tightened. That never used to happen.

Bottom line is there is no way I would use any water fittings on today's tractors - or any of today's water fittings on yesterday's tractors. There's just too much danger to myself, and friends and family.

Use hydraulic pipe fittings; they aren't very much more expensive - and not at all when compared to the danger of using water pipe fittings today.

rScotty

 

[wdchyd]

Seamless black iron pipe avail in hardware stores is only schedule 40 rating.
Schedule 80 (aka extra heavy) or schedule 120 (extra extra heavy) has sufficient wall thickness for medium pressure hydraulic uses but understand although they have the same outer thread dimensions they will not couple up to many steel pipe adapters with FPS (female pipe swivel 30 deg inner cone).
Some manufactures use the sched 80 and 120 pipe for older piping systems along with compatible fittings with same ratings, but they are mostly being phased out.
I don’t like threaded pipe in hyd systems but have learned to tolerate it if keeping in tune with proper wall thicknesses and high pressure fittings.