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J&S540 : some advice needed to assess plan bearing spindle

kaiten

Plastic
Joined
Jan 9, 2011
Location
France
Hi folks !
I am the recent owner of a 1961 J&S540. It is in a definitely shabby state, but from what I could check so far since the rusty turd is at home, the worst part appears to be the outside.
For reasons I will not linger on, I have no certainty about how it lived the past years, but it sure spent some time out enjoying our rainy Brittany.
Motors are good, inlet hoses are new (well, the newest part of the machine at least). Many things probably look far worse than they really are. Hydraulic cylinder rods are bent :nono: from some dude recently trying to lift the machine from under the table, well that's life. Nothing there I cannot handle.

On the upside, I discovered the spindle is indeed a plain bearing variant. Could not anticipate that from the few shots I had been sent before the (almost) gift horse showed up...hence me not looking too deep in its mouth.

I opened up the spindle box cover yesterday to discover there is no oil there to be found... The spindle moves freely though and very smoothly. A good thing the belt is reduced to strings of gunk, if you consider that running the spindle like that would be quite unwise.
From what I understand, a bad plain bearing spindle could be a showstopper for the overhaul I have in mind.

Long story short, how would any of you wise guys assess the condition of the spindle ? I am aware of the adjustment procedure that calls for 1/100 mm axial play (IIRC), but wonder how a seasoned professional would tackle this. Any hints ?

Cheers,
-Phil
 

Mark Rand

Diamond
Joined
Jul 9, 2007
Location
UK Rugby Warwickshire
I would take it apart, clean it all and inspect for any signs of grooving or galling. If there were none, I'd reassemble, adjust, lubricate and run.If there were signs, I'd think about whether a bearing scraper could cure the problem or whether a spindle re-grind was needed.

My J&S 1400 needs new (ball) bearings but it also needs the ways re-scraping. I haven't done it yet, but it will happen in the forseable future.
 

kaiten

Plastic
Joined
Jan 9, 2011
Location
France
Hi Mark ! thanks a lot for your answer.

I will follow your advice, carefully take the spindle apart and inspect it closely.
I bought the machine mostly unseen (well, with a few very bad pictures where the spindle could barely be seen & my untrained eyes could not tell the type anyway) and finding it was a plain bearing type was a true surprise. Scraping may also be on the list. The table ways have no more scraping marks, but it is not scored or scratched at all. The Y ways are very dirty but in a much better condition than many 540 photos I have seen on PM.
No machine is ever intended to withstand the rain, but they are not equally made, and the 540 is by far not the worst I have seen so it seems the internals did not suffer that much.

Cheers,
-Phil
 
Joined
Jan 15, 2005
Location
The Netherlands
One very important thing with plain bearings is the type of oil you must use
Normally in a gearbox I am not critical at all with the oil I dump into it
A plain bearing with 0.01mm play however needs oil as thin ot thinner as water

If all is correct if you give it a swing by hand it should come to a kind of sudden stop rapidly
It should turn with a bit of friction too Not too smooth Too smooth is to much play
I do not know on the J&S but I suspect there will be some kind of pump or pumping action of the shaft to press oil into the gap
Make sure that this is working properly

Peter

PS I found a drawing in this manual
https://onedrive.live.com/?authkey=...D561F!5266&parId=547FE296ECFD561F!239&o=OneUp
I do not see a pumping action anywhere but it can be there anyway Or perhaps the spindle is submerged in oil. I see 2 oilseals at least
Oilseals are not good on a accurate machine like a grinder IMHO
These generate heat Be sure to use the right ones then Perhaps these are low friction types
 

kaiten

Plastic
Joined
Jan 9, 2011
Location
France
Thanks Peter for the wise words of advise.

I just got down to the machine tonight, removed the belt and hand spun the spindle. To my utter surprise, it moved just as you described with a degree of friction. I would have naively believed it should be smoother than a ball bearing assembly of about the same size, but it is not. I was definitely fooled by the inertia brought in by the motor/pulleys when spinning the whole stuff with the belt installed. I learnt something again today!
As per the spindle lubrication, the diagram you point out in the manual does not render it justice as we do not see the oil distribution channel.
I took a shot into the spindle casting and the oil channel is there, fed by oil collected by the moving disk on the spindle shaft from the casting sump. Mine is obviously empty !

IMG_2624.jpg

As I do not have anything at hand below ISO VG10 I will have to shop for some ISO VG2 oil similar to the recommended Mobil Velocite 3.
I will refrain from disassembling the spindle just now, but refill it, run it cautiously a few times and rinse the oil path. The whole spindle will probably have to be torn down eventually to bead blast the casting and stop the rust invasion.
Thanks also for the heads up on the seals, I will look into this too.
Cheers,
-Phil
 
Last edited:
Joined
Jan 15, 2005
Location
The Netherlands
I would not take it apart if it runs like intended after oiling it
And even if it runs too smooth I would just pull in the bearings into their tapered housing to tighten it up a bit
Then run it and see how it goes

Peter
 

kaiten

Plastic
Joined
Jan 9, 2011
Location
France
Hi Peter,
you are damn right : as the saying goes, "if it ain't broke don't fix it".
From my experience bead blasting is pretty hard to do while ensuring no contamination whatsoever goes into the spindle assembly. So I will reconsider & see if regular abrasive methods are sufficient. The bottom of the casting is really crusty with rust as a result of probable extended outdoor storage.
Cheers,
-Phil
 

ballen

Titanium
Joined
Sep 25, 2011
Location
Garbsen, Germany
Hi Phil,

My Studer RHU-450 has a plain tapered bearing, here are some photos and notes from when I adjusted it. The following posts contain useful comments from Richard and others here: https://www.practicalmachinist.com/...-rhu-450-1960s-343863/index4.html#post3134522

On that machine, the taper is 1:10, and the instructions are adjust it so there are 50 microns of axial (end) play. So dividing by ten, that leaves 5 microns of radial play. In operation, that gap is taken up by an oil film.

Cheers,
Bruce
 
Joined
Jan 15, 2005
Location
The Netherlands
Hi Phil,

My Studer RHU-450 has a plain tapered bearing, here are some photos and notes from when I adjusted it. The following posts contain useful comments from Richard and others here: https://www.practicalmachinist.com/...-rhu-450-1960s-343863/index4.html#post3134522

On that machine, the taper is 1:10, and the instructions are adjust it so there are 50 microns of axial (end) play. So dividing by ten, that leaves 5 microns of radial play. In operation, that gap is taken up by an oil film.

Cheers,
Bruce


Mmmm Aba dictates 0.01mm endplay on their FFK350


A bit OT perhaps but these machines have a different design as the bearings have a straight spindle and the bearings have a tapered OD in a tapered housing
endplay is adjusted by pulling the bearing in The bearing has 3 ridges on the OD So when pulling the taper in you automaticly hold a 3lobbed bearing on the ID (Good bearings are scraped 3lobbed) which creates 3 times the pumping action of a perfectly round bearing
These ABA FFK350 were highly regarded over here Every mouldshop had at least one And they always wanted the best of the best
Peter

attachment.php
 
Joined
Jan 15, 2005
Location
The Netherlands
On that machine, the taper is 1:10, and the instructions are adjust it so there are 50 microns of axial (end) play. So dividing by ten, that leaves 5 microns of radial play. In operation, that gap is taken up by an oil film.

Cheers,
Bruce
Looked it over one more time
Radial play of 0.05mm is on both sides of the taper So the axial gap of 0.005 is also on both sides , with the shaft centered That leaves a endplay of 0.01mm Like on the ABA
0.005 seemed so little to me

Peter
 

kaiten

Plastic
Joined
Jan 9, 2011
Location
France
Hi Bruce,

Thanks for the heads up on this fantastic thread about the Studer,! it is packed with information. You have really been doing an impressive job with it.

It take due note of the specifics of this tapered bearing, and will try and apply when I can dedicate time to check it. Day work is a bit over my head right now, but this will come.
I have been busy parting the machine, assessing the areas where it needs urgent action and checking if anything looks like a showstopper - not the case yet despite a very ugly appearance. Shabby to say the least, but I have good surprises too as I go, like the Y leadscrew which is in a very good state (could not reach to the nut yet). It all points to a machine that was in a very decent condition (so I am told by one of the former owners, not the last one, who saw it in operation), but that was subsequently left outside being weathered. It was then sheltered for about a year before I got it, but the damage was started. The internals look seasoned and grimy but nothing really damaged. The start/stop mechanism for auto cross-feed has a broken part I found in the belly of the casting, but this looks fixable. Emergency is to dismantle and sandblast the casting parts to put them out of reach of corrosion and buy me time.
Cheers,
-Phil
 

ballen

Titanium
Joined
Sep 25, 2011
Location
Garbsen, Germany
Hi Peter,

I do not like to sandblast a machine. For that it has to get disassembled completely.
It also has the potential of introducing stresses in the casting that can warp things.

I think Phil intends to take everything apart before sandblasting, so that's not an issue. But I never realised that sandblasting could warp a casting. I know that peening a steel part can introduce compressive stresses and bend/warp it, so it makes sense that sandblasting a cast-iron one might have the same effect, but I have never heard it before. Have you seen this yourself, or just heard about it?

When I fixed up my J&S 540, I ground the "table pad", and was worried about that warping the table. But I was careful not to burn it, and based on before/after measurements, I did no damage. Here is the "before" and the "after":

https://www.practicalmachinist.com/vb/abrasive-machining/horror-under-chuck-324747/#post2826950

https://www.practicalmachinist.com/...or-under-chuck-324747/index3.html#post2896025

The table pad is quite small compared to the entire table, and it is also broken up by a deep T-nut slot running down the middle. I think that geometry makes grinding the surface of the pad less likely to warp the entire table. But I was very cautious about doing it!

Cheers,
Bruce
 
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Joined
Jan 15, 2005
Location
The Netherlands
It depends how it is sandblasted But doe you have any controle over it
With steel shots and a turbine sandblaster it can be very harsh I know from experience
So why take the risk Escpecialy when you have nice old aged cast iron

A alternative would be chemical stripping A shop nearby is specialized in depainting and can eighter burn it off, sandblast or chemicaly remove paint and filler

Peter
 
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ballen

Titanium
Joined
Sep 25, 2011
Location
Garbsen, Germany
It depends how you sandblast it. With steel shot and a turbine sandblaster it can be pretty harsh, I know from experience.

Yes, I can believe that steel shot at high velocities can peen and warp metal! I've always used much finer media, crushed glass and fly ash (I think that's what it's called). I find it hard to image that those can warp parts, but perhaps I am wrong.
 
Joined
Jan 15, 2005
Location
The Netherlands
Yes, I can believe that steel shot at high velocities can peen and warp metal! I've always used much finer media, crushed glass and fly ash (I think that's what it's called). I find it hard to image that those can warp parts, but perhaps I am wrong.


But with that media it takes forever to clean up a whole machine
I imagen he wants to outsource the sandblasting
 

ballen

Titanium
Joined
Sep 25, 2011
Location
Garbsen, Germany
Did you see my post 10 ? Can you agree with that ?

Peter, I am just not sure. My only direct experience with spindles and spindle bearings is with my own machines, and only one of those has a solid journal bearing. So to tell the truth, I just don't trust my own opinion. You and other people here have much more experience than I do! But doesn't the J&S 540 manual explain exactly how to set the bearing clearances?? Cheers, Bruce

PS: here are instructions from my J&S 540 manual. If I have understood correctly, you set the clearance by first "seating" the spindle by tapping it tight into the housing. Then you measure the radial clearance as you pull the wheel spindle forward as far as possible. This requires 10 microns of radial clearance or 20 microns of diameter clearance. Seems like a lot, no?

attachment.php
 
Joined
Jan 15, 2005
Location
The Netherlands
Peter, I am just not sure. My only direct experience with spindles and spindle bearings is with my own machines, and only one of those has a solid journal bearing. So to tell the truth, I just don't trust my own opinion. You and other people here have much more experience than I do! But doesn't the J&S 540 manual explain exactly how to set the bearing clearances?? Cheers, Bruce

PS: here are instructions from my J&S 540 manual. If I have understood correctly, you set the clearance by first "seating" the spindle by tapping it tight into the housing. Then you measure the radial clearance as you pull the wheel spindle forward as far as possible. This requires 10 microns of radial clearance or 20 microns of diameter clearance. Seems like a lot, no?

attachment.php
Bruce

To me it looks like that they mean thrustclearance of 0.01mm (axial clearance )
Also this documentation is for a spindle with angle bearings it looks like



BTW in my post 10 it was your Studer we were talking about
and my point was that if you have 50 microns of axial (end) play. with a 1:10 taper the endplay or diameter clearance is not 1/10 of axial play but 1/5 IMHO



Peter
 








 
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