Jones and Shipman Hydraulic pump help

I’m busy cleaning and refurbishing a grinder. It was in a ver6 sorry state when I got it. The tank was full of grinding Gupe so I’m think8ng of taking apart the pump to clean it out rather than just flushing it through with new hydraulic fluid. Here is a schematic of what I will find inside. Now, hydraulics are something relatively new to me, and I don’t know a lot about them. I haven’t so far had a need to poke my fingers into hydraulics, but I’m very very aware how dangerous a squirt of it can be if you get it wrong! So, I’m very cautious about playing with this stuff, I don’t want to have bits of me cut off due to having it inadvertently injected into me!!

So, here are my thoughts, hopefully any hydraulic experts can correct my perceptions.
There appears to be just three sealing parts, two copper gaskets and a stuffing ring. I think I can reuse everything? I dont think I will need to replace the copper gaskets as long as I carefully mark which side , way around they are and pop them back in the same way? Not sure what the stuffing ring is made from but hopefully that is just some form of fibre rope?.

There are two pipes up to the machine from the pump. It looks like there are two pressure pipes into the machine, from reading other posts I think the centre one is the high pressure port and the one above the Exhaust pipe (S) is a low pressure outlet. So firstly, any experts, does this sound about right? Can you see any issues in taking this apart and rebuilding it? Anything I should be careful about / pointers for reassembly?

Your estimate of the danger level from the hydraulic system is probably unfounded. These machines use pretty low pressure, probably under 200 psi. The dangerous stuff is generally an order of magnitude higher. Anyway, the pressure in a grinder generally drops to zero everywhere as soon as you shut it off.

As for your other questions, you should drain the oil out of the machine by pumping it out, then clean the sump bottom well and refill with fresh oil or filter the old oil and re-use it (if it's old, might want to change it). Disassembly of the system is probably unnecessary if everything is working okay. You can flush it if you want to use a little extra precaution. I pulled the hydraulic system apart on my 30 year old grinder recently and the insides were clean as a whistle.

Jones and Shipman 540P hydraulic tank

Thanks for coming back, I blundered and should have stated it’s a 540 grinder in the title. The sump has been emptied and cleaned, it was thick with grinding goo. I don’t think it had been emptied / oil replaced since the day it was new. I’m concerned that the goo is inside everything, and after tearing it all down and building it back up I could be back at the start with bits coming through.

Did you need to replace the gaskets or could you reuse them?

I’ve added some photos of the before and after cleaning and where I am with it at the mo.

I’ve replaced the mentalastik mounts and the sprockets and chain which were worn out.

eKretz said:

Your estimate of the danger level from the hydraulic system is probably unfounded. These machines use pretty low pressure, probably under 200 psi.

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I did some adjustment of the pressure on my J&S 540, and as I recall is was about 6.8 or 7 bar = 7 x 14.7 pounds per square inch ~ 105 PSI. Wear some eye protection but caution rather than fear is appropriate.

For the OP: I would remove the pressure regulating spring and plunger from the pump, clean those well, and ensure that the parts fit nicely and move smoothly. Then reassemble and follow the J&S directions for setting the pressure. Parts are shown here: https://www.practicalmachinist.com/...-j-s-540-hydraulic-system-380392/#post3596756 . Provided that you can set the pressure correctly, I am guessing that everything will be fine and that tearing down the pump is more likely to do harm than good. If it ain't broke, don't fix it.

You should lift off the table (remove the piston rod attachments first!!) and make sure that lubricating oil is weeping out onto the ways (visible in the photo below, one on the V way and one on the flat way). The adjustment valve is hidden inside one of the levers/controls (have forgotten which one). If one of those oil holes is blocked it will cause premature wear in the ways.

Important: if you replace the hoses, be sure to use the correct material. If you use stiff high-pressure hose it will transmit a lot of vibration into the system. You need a soft hose which acts as a damper for vibrations from the pump, but not so soft that it will tear and burst. A good choice is Semperit TU25 hose in 1/2" or 5/8" ID.

These machines have a well-deserved reputation for longevity. So even if the sump was full of grinding grit, it probably settled to the bottom and the mesh filter and overall design prevented it from reaching the sensitive bits upstairs. Good that you cleaned it out in time. How do the long ways look, on the table (top) and the V/flat (bottom)? Can you still see scraping marks? Here is what it should look like (original factory scraping):





Cheers,
Bruce

Thanks Bruce,
I was going to do a thread in this forum about taking it apart and putting it back together. However, I can’t find a way of adding full size, proper pictures. All I’ve managed to post is very reduced thumb nails. So, I’ve actually started a thread on a different forum that allows full sized pictures.

I tried to find a thread on taking one apart and putting it back together before I bought mine, however I came up with nothing, but found this forum.

The thread is here
Jones and Shipman 540P Rebuild | UKworkshop.co.uk


I’m assuming my understanding of the high pressure outlet is correct, and having read your suggested thread I think adding a permanent pressure gauge is a good idea.

There is still the slightest whiteness marks of the hand scraping left, not much. I’m wondering whether to attempt to re scrape it? Nit something I’ve ever done before, and from what I’ve read so far in other threads, a grinder isn’t usually a first time project. Anyway, once I’ve put it back together I will test it and then make a final call.

Deema said:

All I’ve managed to post is very reduced thumb nails.

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(0) Create an Album

(1) For each photo that you want to display in a post, upload to the Album, then get the "BB pointer" to the photo and paste it into your post.

(2) Note, when uploading, .jpeg and .jpg files are NOT equivalent! One of those will result in good full-size photos like the ones above. The others will be shrunk to tiny.

There is still the slightest whiteness marks of the hand scraping left, not much. I’m wondering whether to attempt to re scrape it? Nit something I’ve ever done before, and from what I’ve read so far in other threads, a grinder isn’t usually a first time project.

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I suggest that you remove the moving table, turn it upside down on some sawhorses, take a good quality photo and post it here. Clean off the top V and flat on the saddle, take a good quality photo, and post that as well. Like the last two photos in post #4. This should get you some useful feedback from the pros here.

If you look here (start around post #30), you will see that I scraped "square-cut" oil pockets into the ways of my Studer RHU-450 grinder. This was a 'first scraping project' for me, with lots of help from Richard King and other experts. If you can get someone experienced in the UK to visit you for a day or two, it can be done in a few hours. I recommend that you do that for your J&S 540. It should not change the geometry but will result in better lubrication and no stick-slip.

Cheers,
Bruce

I’m struggling to identify the thread on the fittings connecting the hoses to the pump. I want to both test the pressure being created and fit a permanent pressure gauge without interfering with the hydraulic pipes as I understand they act as accumulators. They thread seems measure 18mm at the top and appear to taper to 17.5mm with a 1.5mm pitch. Are they metric M18 pipe fittings of 1/2” NPT or something else?? I’m a newby to hydraulics so this is a bit a learning curve

Deema said:

I’m struggling to identify the thread on the fittings connecting the hoses to the pump. I want to both test the pressure being created and fit a permanent pressure gauge without interfering with the hydraulic pipes as I understand they act as accumulators.

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For setting the pressure I suggest following the instructions in the manual closely. On my machine this means leaving the hoses connected to the pump but instead removing the small plastic tube that goes to the distribution manifold and attaching the pressure gauge there. Do you have a manual? On mine it is shown as Figure 16 item 1. I don't recall what the thread was.

My machine (J&S 540APR) has a distribution manifold at the bottom rear. That had some unused ports, so I just ran a new line from one of those ports to the gauge that I added. I brought the blanking plug to a local hydraulic place and they provided a suitable fitting.

Deema said:

I’m struggling to identify the thread on the fittings connecting the hoses to the pump. I want to both test the pressure being created and fit a permanent pressure gauge without interfering with the hydraulic pipes as I understand they act as accumulators. They thread seems measure 18mm at the top and appear to taper to 17.5mm with a 1.5mm pitch. Are they metric M18 pipe fittings of 1/2” NPT or something else?? I’m a newby to hydraulics so this is a bit a learning curve

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Historically, they were BSPT (British Standard Pipe - Tapered), which is still the standard pipe thread in the UK and pretty much all of the world except the US (the standard ISO pile threds are BSP!)

If you are measuring with an internal caliper, go for the core diameter, is measuring the external diameter then use that:-

Size Thread Dia/ Dia/ Pitch Pitch Core Core Depth Depth
Name Inch mm TPI mm Dia" Dia mm Inch mm

3/8 BSP 0.656 16.662 19 1.337 0.589 14.961 0.0335 0.851
1/2 BSP 0.825 20.955 14 1.814 0.734 18.644 0.0457 1.161

Thanks for your reply, mine is an older machine without a distribution manifold, the hoses connect directly to the pump unfortunately.

Thanks for getting back, I should have said I’m measuring the male nut, it’s definitely measuring the OD (not PCD) a max of 18mm, which is what is causing my head scratching. I was expecting BSPT, which I don’t believe it is!

Deema said:

I’m measuring the male nut, it’s definitely measuring the OD (not PCD) a max of 18mm, which is what is causing my head scratching.

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Metric 12L hydraulic fittings are an M18x1.5mm thread, but I believe that they are parallel not tapered. Here are some typical fittings:
Gerade Verschraubung Hydraulikverschraubung Schneidringverschraubung 12L M18x1,5 | eBay