Jones and Shipman 540P Rebuild (Round 2)

[deema]

There are parts of the design of this machine that seem unusual to me. The lubrication of the cross slide has been troubling me for some time. The main table has hydraulic fluid pumped into the ways to both provide lubricant and also to wash away anything that gets into them. I would have expected that the cross slide table ways would also be similarly lubricated, but they aren’t. The cross slide ways rely on the hydraulic oil from both the table ways and any leaks from the piston dribbling down into them.

The photo shows the two holes that the hydraulic oil has to flow down to the ways. I had assumed there would be a drilled gallery to these, but there isn’t.

These holes sit right beneath the main table actuating cylinder, so there is no access to them for a user to lubricate them. It’s just a rough cast area, so unless the grinder is precisely level, and with luck the cast body is also level, the hydraulic oil, will not lubrucate one side.

This is where the two holes come out, either side of the V ways, there are two V ways, one on each side, so 4 drain holes in total.

To add to the mystery, there is also a reservoir cast into the body to lubricate the manual table actuator, and also a collector to feed oil back down the drain pipe to the hydraulic tank. These are shown with arrows showing the way the oil will flow.

So, I cannot see how it’s possible to be certain that either of both of the cross slide ways will receive any lubrication. If anyone has any better knowledge / observations I’d appreciate your input. This is a design that hasn’t changed much and the machines are know to be reliable / accurate for years. I’m wondering if I’m missing something?

 

[TFrench]

Is it just a case that theres so much oil running about then its likely to get some at some point?
Did you manage to find your leadscrew and nut to match the old one? So all the graduations on the dial will still be right?

 

[AndyPandy64]

I had to replace my cross slide screw and nut on my 540. You are correct, it is a 2.5tpi multi start thread. If you use a 5tpi screw you will have to turn the handle twice as much for the same distance.

I've got a Colchester student 1800 and by some miracle I figured out that you can do a multi start thread on it (only 2 threads) by using odd and even numbers on the thread dial. A lucky find for me since its not documented

I bored out the nut and made a insert that I threaded. It ended up being an extremely thin walled part and I had be careful with holding it in the chuck because the more thread I took the thinner the wall became and the more the chuck squeezed it. Ended up using a long piece and holding it in the chuck about half way and only threading the end that was not held by the chuck. Must admit I was quite chuffed with myself since it was the first thread I'd had to make in anger !!! Probably took me a day in total, including lots of practice parts in steel

If I can do it, anyone can. And best of all it cost next to nothing all. Maybe £30 in total

 

[AndyPandy64]

I modelled both the cross feed screw and nut insert a few years ago and the below are links to Fusion 360 models of both the Cross Feed Screw and the nut insert in case anyone needs them

Note the thread on both is not a two start ACME thread. I just modelled something

Nut insert
Screw

I've attached F360 model and drawings

I was to scared to drill the 5mm diameter 110mm deep grease hole. In my defence I dont have a bit long enough. And I dont use it that often

 

[Jordhandson]

good post well done

 

[TFrench]

Deema, massive thanks in order for this thread. I've just got one of these and having prior knowledge of what I was diving into from this thread have made it much easier!

 

[deema]

TFrench, you don’t have one if there aren't any pictures!
I’m delighted the thread was of help to you.

 

[TFrench]

I just need to find time to sort my pictures out into a proper post, but here she is coming out of the van. Suspect my poor van was a bit overloaded with this one!

 

[Saxguy]

This has to be the best helpful thread Ive ever seen on the J&S 540.

 

[hennebury]

Great thread, nice machine. You have to be a bit of a detective to do machinery rebuilds, I get nervous going on if I don't understand something. Really interested in seeing the rest of the rebuild. I have a German grinder, not overly impressed with the design, so I look forward to seeing how yours is all done.

 

[Saxguy]

Great thread, nice machine. You have to be a bit of a detective to do machinery rebuilds, I get nervous going on if I don't understand something. Really interested in seeing the rest of the rebuild. I have a German grinder, not overly impressed with the design, so I look forward to seeing how yours is all done.

I love delving into projects such as this. Yes, I'm a sick puppy!
Its so much easier now we have digital cameras and the internet mind you. Used to have a jotter and a pencil and hope for the best!
You couldn't have said it better when you said that you need to be a bit of a detective. You look for things like witness marks, scuffs and scrapes, and they all tell a story, especially when reassembling (if you haven't polished them all up that is!)
Get yourself a whole load of plastic boxes with the clip on lids. As well as different size plastic bins too (fish bins sometimes they are called), and with lids if possible.
As you start to disassemble, photograph and video the whole job, or at least areas where you are likely to have to remember, ie stacked washers/bearings/gears etc etc. Nothing more terrifying than having stripped down a gearbox, and a month later trying to remember what order the whole lots goes back in!
And then use the various boxes for each 'part' of the machine. eg handle & cross screw assembly. Large parts in one of the large bins, and the smaller parts inside a small container placed with the larger parts in the large bin, and so on. LABEL THE BOXES/PARTS ACCORDINGLY.
Then make a note of whats in the boxes, along with any suspicious findings (sometimes things have been adulterated and/or reassembled incorrectly before you even get them!).
Also, make sure you have, or think you have, the right tools to do the job before you start. Also, space. Assess how much space you think you will need, then double it!
Then..... let the fun begin!

 

[Badee]

Jumping back to the cross slide, the actuator that stops the automatic feed if the cross slide I haven't previously shown.
View attachment 113582

Once the grub screw is removed, the shaft should slide out, right? I don't see anywhere to tap it out from behind, but don't want to grip the end and potentially damage it - yes, mine feels wedged in there. Any advice on removing this?

 

[Badee]

A bit more measuring of the leadscrew to see what room I have to play with.
The central pocket is where the lead screw sits, the lead screw can’t be seen when the casting is popped back onto the machine. so first job is to temporarily put the screw back in.

View attachment 113586

My next question involves removing this cross saddle. I see 2 hoses connected to it if I shine a light past the valve block, which I'm assuming is the hydraulic oil feed (and drain?) lines to the cylinder block. I see yours are plugged in the image above. But I don't see a way of removing this saddle. Is it bolted down at some point (where it is still allowed to move forwards and back)? Or is it just one heavy casting that needs to be lifted?

 

[deema]

The saddle is just ‘sat’ on the slides. Extremely heavy, and lifts off when the hoses are disconnected.

 

[deema]

Once the grub screw is removed, the shaft should slide out, right? I don't see anywhere to tap it out from behind, but don't want to grip the end and potentially damage it - yes, mine feels wedged in there. Any advice on removing this?

Yep, it’s not easy to get it out. You don’t need to remove it to lift off the saddle. I did so just to clean around it.

 

[AndyPandy64]

Thanks Paul, appreciate your perspective on the ball screws. The thread is definitely Acme, and a very unusual size for 3/4”. I had hoped I could buy it ‘off the shelf’ to make replacing it an easy exercise. Unfortunately I can’t find anything thats an exact match of the pitch. So the choice is going to be either use trapezoidal which I can get in 10(2) 21mm which will just fit (nearly 2.5TPI), get some made, or find some change gears for my Cholchester Student as the quick change gear cutting box only goes down to 5TPI. ……or bite the bullet and pay for a replacement.

I see you have a Colchester Student. I've got a Student 1800 and had the same problem. You are correct that the thread is a two start 2.5tpi ACME. I found out the hard way, but fortunately had just made a test nut to check the fit on the unworn ends of the lead screw

I found, by accident (or ignorance) that I can easily cut a two start 2.5tpi thread on my Colchester Student 1800. First set everything up to cut 2.5tpi as per the front plate. Then to get the two starts I just used alternative odd numbers on the thread dial, ie '1' for one thread and '3' for the other. Appears to be a non documented feature. Or just a lucky find

I bored out the bronze nut and made a threaded sleeve which I Loctited in place

Scarily this was my first every thread I cut on my mid life crisis lathe. Its not a great thread, to much play (didn't factor in tool wear), but it works well enough that I am still using the screw and nut 3 years later

 

[J-G]

I found, by accident (or ignorance) that I can easily cut a two start 2.5tpi thread on my Colchester Student 1800. First set everything up to cut 2.5tpi as per the front plate. Then to get the two starts I just used alternative odd numbers on the thread dial, ie '1' for one thread and '3' for the other. Appears to be a non documented feature. Or just a lucky find

??? That doesn't ring true. If you set up for a 2.5tpi thread (0.4" pitch) then that is what you will get - you could get a two start thread but the pitch will be 5 tpi (0.2") and you would have to use a half size tool and only cut 0.105" deep.

Since this is your first thread, you may of course be confused by thread nomenclature and are quoting the 'Lead' of the two start thread rather than the TPI (Pitch).

 

[AndyPandy64]

??? That doesn't ring true. If you set up for a 2.5tpi thread (0.4" pitch) then that is what you will get - you could get a two start thread but the pitch will be 5 tpi (0.2") and you would have to use a half size tool and only cut 0.105" deep.

Since this is your first thread, you may of course be confused by thread nomenclature and are quoting the 'Lead' of the two start thread rather than the TPI (Pitch).

You are probably correct

I measured the cross lead screw thread with a pitch gage, its a 5tpi thread. So my practice nut was a 5tpi. I was then confused then it did not fit on to the old lead screw. Eventually I figured out its was a two start 2.5tpi thread. If, on my Student 1800 you set it up for 2.5tpi and cut a two start thread you end up with what appears to be a single 5tpi thread.

But yes. first thread and know nothing about 'thread nomenclature' or much else for that matter

Like I say more my dumb luck finding out my Student 1800 will do very odd two start threads. That was the bit of info I was try to pass on

 

[J-G]

You are probably correct

I measured the cross lead screw thread with a pitch gage, its a 5tpi thread. So my practice nut was a 5tpi. I was then confused then it did not fit on to the old lead screw. Eventually I figured out its was a two start 2.5tpi thread. If, on my Student 1800 you set it up for 2.5tpi and cut a two start thread you end up with what appears to be a single 5tpi thread.

But yes. first thread and know nothing about 'thread nomenclature' or much else for that matter

Like I say more my dumb luck finding out my Student 1800 will do very odd two start threads. That was the bit of info I was try to pass on

First - That's one hell of a thread for your first !! - Since you admit that you are new to threads, I presume that you may not even know the correct flank angle of an ACME thread -- this may also be why you think that you omitted to consider 'Tool wear'. To measure the wear after cutting a single thread in Bronze, would be difficult even with the most sophisticated inspection equipment, so I suggest that you have cut it too deep or not at 29°

There's nothing unusual about an OD of 3/4" - though that Dia. would normally be a 6tpi ACME - as it happens ACME threads are very much designed to transmit power, and 2 start more so, therefore all the 'standards' go out of the window.

What dia. did you machine the 'bore' to? And how deep did you make the final cut? - - - For a full depth thread the bore should have been ~ 0.55" and the thread depth 0.1" but since it is two start, you should have also taken note of the Helix Angle when selecting the tool. With a 5tpi Lead and 0.75" OD the helix angle is close to a massive 11° 5' so if you were using a 'standard' ACME Thread Chaser the clearance should have been modified - there would have been 'rubbing' on the flank which would affect the thread form - potentially causing the poor fit.

 

[sawtooth-9]

I have restored two surface grinders, but nowhere near the quality of this gear.
NEVER let it go