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

    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 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

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    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.

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    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

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    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=%...%21239&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

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    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 by kaiten; 11-25-2021 at 03:44 AM.

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    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

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    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

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    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: Studer RHU 450 from the 1960s

    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

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    Quote Originally Posted by ballen View Post
    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: Studer RHU 450 from the 1960s

    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


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    Quote Originally Posted by ballen View Post


    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


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