home made press hydraulic press question (wont hold billet for twisting)

Not sure what the deal is for sure, but it might be an "open center" vs a "closed center" on the valve. On the RD-2575-M4-EDA1 I read "Open center to closed center conversion available on some models". I've not been able to confirm for sure which of the Prince valves is Open Center that allows fluid to flow in center position. The chart posted later shows a "4 way 3 position" and a "4 way 3 position motor". It seems the difference in those valves is the "T4" vs "M4" in the model number.

Note in the drawing posted at bottom it shows how to change from "Open" to "Closed" by using a NPT plug for some model valves.

A question was asked on Surplus Tools about D-2575-M4-ESA1 and the answer was "the work ports are open to tank in neutral.". Can you tell which model number you have?

edited above to correct some stuff.

Ken H>
 
Last edited:
Since we're not allowed to post links to an educational page, you can do a google search on "OPEN AND CLOSED CENTER HYDRAULIC SYSTEMS" for a link to the full article where the quote above came from.

Per the drawing on the first page of this thread, that control can be chance from open to closed by adding the 3/8" NPT plug as shown in the drawing. Looks like you're in luck.
 
Last edited:
Ken H> said:
There's your answer right there, the "ESA1" is an Open neutral which allows the cylinder to move with control n the center position. Looks like you need the "EDA1" which I "understand" (understand, not "Know for sure) is Closed in the neutral position.

Per the drawing on the first page of this thread, that control can be chance from open to closed by adding the 3/8" NPT plug as shown in the drawing. Looks like you're in luck. i know nothing with these setups? not even sure what to do but thanks
Click to expand...
 
Ken H> said:
There's your answer right there, the "ESA1" is an Open neutral which allows the cylinder to move with control n the center position. Looks like you need the "EDA1" which I "understand" (understand, not "Know for sure) is Closed in the neutral position.

Per the drawing on the first page of this thread, that control can be chance from open to closed by adding the 3/8" NPT plug as shown in the drawing. Looks like you're in luck.
Click to expand...
 
Understand, I am NOT a hydraulic expert either. All my knowledge about this situation has been from my reading and research over the last few days. I "think" I have a handle of the situation, but please note the "I think", and NOT "I know". :)

From what I understand from the drawing, looking at the port marked "outlet", remove that hose fitting, look inside and you "should" see a threaded hole. Take a 3/8" NPT plug with a hex wrench and screw into that threaded hole. That should prevent the fluid from flowing when in neutral position. Since we can no longer help folks by posting links, this is the item # B08NJ91H24 from Amazon. Just do a google search on that number and it should be the first item listed. OR, you can go to Amazon and paste that number into the Amazon search bar and it will bring up the 3/8" NPT plug with internal hex.
 
I'm not totally sure which is the correct part number. You mention below you have a "M4-ESA1" part number, that looks like that is the "4 way 3 position motor" type valve and is a spring return.

Looks like I'm showing everybody just how much I'm NOT a hydraulic expert.
 
Last edited:
Ken H> said:
I'm not totally sure which is the correct part number. See my edited post in thread #24 above for more discussion. Looks like I'm showing everybody just how much I'm NOT a hydraulic expert.
Click to expand...
ken your the man appreciate all your help ill put a plug in tomorrow i ordered 1 earlier on amazon will post my findings as soon as i can thanks to everyone who has been trying to help me you guys are awesome 👍👍:) Mark
 
Remember, you're using a positive displacement pump and as long as the pump is running, it's going to build pressure, which will be relieved by the internal hi-pressure bypass in the control valve. That's where the max pressure is set.

Hey, you've got the plugs ordered, pretty easy to install. Just BE SURE the first time you turn pump on with valve in center position to watch pressure gauge closely to turn pump OFF if pressure starts building too much. BUT, as mentioned other places this should not be a problem as the hi-pressure adjustment sets the max pressure before the fluid is bypassed back to the tank.

Remember, I do NOT know much about this stuff and am learning.
 
Last edited:
Do you have a post vise you could use that. If you can build a press I made a simple twisting jig with square tube welded on the ends. On a safety note I would cover the hoses.
 
You must log in or register to reply here.
Back
Top