Jones and shipman universal grinder
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  1. #1
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    Default Jones and shipman universal grinder

    Has anyone got advice on how much damage is caused in our wheelhead?

    I switched on the machine last week and the wheel stalled after a couple minutes and the motor cut out, noticed the oil had dropped very low,

    I managed to get my manager to buy the proper oil the replace it, filled it up today and started the wheel, it stalled straight away and I noticed The new and very thin oil was leaking heavily out the seal behind the wheel.

    So apart from the obvious seal that needs replacing, will the bearings be toast too? The motor is fine as the overload cut out worked as it should.


    ( oh and by the way, when I told my manager about the problem, he turned round and said ďthat must be why I put hydraulic oil in before, so it didnít run out so fastĒ, facepalm. )

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    There are several Jones and Shipman users on this forum. `However it's August and they will not be back from vacation for another two weeks. I will attempt to answer your questions, so as not to leave you in suspense, even though I know nothing about the J & S grinder .

    The work head spindle uses a oil slinger disk and a labyrinth seal to prevent oil from leaving the spindle housing. The oil collects at the bottom of a well and drains through a hole into the oil sump. The oil is overflowing on your spindle and leaking out through the bearing cap because the oil well drain hole is plugged up.

    The reason your management is using a ISO 32 oil rather than a ISO 5 spindle oil is because the spindle and journal bearings are scored. The ISO 5 oil has about 1/4 the viscosity of the ISO 32 oil. The thicker oil allows the bearing clearance on the adjustable journals to be set to twice the distance of what the manufacturer intended.

    The wheel spindle supported on the hydrodynamic bearings rotates about a center that is offset from the bearing geometric center. The amount of offset is a function of bearing clearance, spindle speed, bearing diameter, oil viscosity and spindle load. The thick oil and large clearance will make it difficult to approach a specified diameter on a bar being ground. The spindle center of rotation will change with grinding wheel load. The spindle will also pivot about the bearing supporting the pulley as the wheel load changes. You may end up with a barber pole pattern on the ground shaft.

    There will be no oil pressure to support the rotating spindle If there is no oil in the hydrodynamic bearing or if the oil viscosity is too small for the bearing clearance.

    When this happens the rotating shaft will climb up the journal surface. The height that it moves is determined by the spindle load and by the friction between the spindle and journal. If the loads and friction are identical at both the left and right side bearings the spindle height will be the same at both sides and the spindle will remain parallel to the bore. If the loads are different at the two ends the spindle will be tilted slightly and will bind in the journal bore. The binding will not occur if the journal bearings are on spherical seats. The bearings will realign for the tilted spindle. If the bearings are held fixed in position the spindle will jam and stall the wheel head motor.

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    Hi,

    Thanks for that explanation, was easy to understand, so does this mean that the seal may not need replacing? And this binding that is occurring, will it cause the bearing to need replacing? Or is it possible to change the bearing clearance like on a preloaded type? Is it easy to get to the drain hole?

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    The labyrinth seal should have no wear under normal operating conditions. It could be damaged if grit or water found its way into the seal. I cannot answer the questions about wheel head disassembly, cleaning, or bearing adjustment. You may receive a better answer if you repost the question on the machine rebuilding forum. There should be someone there who has adjusted a J&S journal bearing and who could describe how to clean up the spindle and journal surfaces if they are scored.

    There is a product called "Timesaver" or something similar that is a non embedding abrasive. It comes in three different grit sizes.The abrasive is applied to the journal and the spindle rotated by hand to remove burrs. The grit is then rinsed out and the process repeated for the finer size. The process is not complicated and it may be sufficient to restore the journal surfaces.

    You could also bring the spindle and wheel head to the local engine machine shop and have them use their honing equipment to clean up the spindle and journal surfaces.
    Last edited by Robert R; 08-23-2019 at 10:30 AM.

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    I'm a fan of the Timesaver lapping compounds. They come in four different grit sizes: very fine, fine, medium and coarse. Timesaver Lapping Compounds - WS2 Coating The green ones are for steel and cast iron, and the yellow ones for brass and other softer metals.

    I had always read that spindle journal bearings on grinders were scraped to fit, not lapped, but the idea of trying to remove damage with lapping makes some sense. My question is, since the spindle is steel and the bearing surfaces are brass or bronze, which flavor of lapping compound (green or yellow) would be appropriate?

    A "test kit" of four different small cans of Timesaver lapping compound costs about $40 delivered. My test kit has lasted a few years and there is still plenty left.

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    Quote Originally Posted by ballen View Post

    I had always read that spindle journal bearings on grinders were scraped to fit, not lapped, but the idea of trying to remove damage with lapping makes some sense. My question is, since the spindle is steel and the bearing surfaces are brass or bronze, which flavor of lapping compound (green or yellow) would be appropriate?
    .
    The easiest approach is to resurface the hardened steel spindle and then use the spindle as the reference for fitting the bronze bearing. The spindle can be resurfaced by making two end caps to allow it to be mounted on centers. The bearing surface can then be cleaned up by turning at maybe 100 RPM with a V-block holding a abrasive cloth against the spindle bearing seats. The goal is to remove the high spots and smeared bronze on the spindle while preserving the geometry. The high pressure at the two line contacts will tend to slice off the high spots. Or take the spindle to a engine shop for honing.

    The radial spindle clearance on the floating shoe type journals is roughly .0003 inches. There are some designs where it can be less than .0001 inches.

    Neither honing or the V block lapping requires perfectly centered end caps. Both methods float on the existing surface. OD honing will make a oval shaped bearing surface circular. It uses three lines of contact. The V block method, at best, will not make a circular profile oval shaped.

    The journal is likely to consist of three 120 degree pads mounted on pivots. Two of the pivots are fixed to the wheel head housing. The third pad is adjustable radially to set the bearing clearance. The Timesaver abrasive can be used to erode the high spots on the bronze pads using the resurfaced spindle.

    The bearings are adjusted by placing a thermometer in the oil sump and gradually reducing the clearance while the spindle is running. The clearance is set for a 40 deg C temperature rise above room temperature.

    A digital amp meter connected to one of the three motor leads will be very useful. A 3 degree turn of the right side bearing adjusting screw may, for example; causes a 0.2 amp increase in the motor current. The left side bearing is then tightened for the same 0.2 amp increase.As the clearance is reduced the same 3 degree turn of the screw will produce larger increases in the motor current. At some point a 1 degree increment in the adjusting screw will cause a 5.0 amp increase in the motor current. At this point you will know that the spindle is about to lock up and it will be necessary to back off the adjustment screw.

    Copies of the operation and maintenance manuals for the J&S cylindrical grinders are available for 50 Pounds from Jones & Shipman Grinding Machines
    Last edited by Robert R; 08-24-2019 at 11:29 PM.

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    Hi Robert, thanks for your time to reply,

    Given all the technicalities of using a thermocouple and amp meter to help set the bearing clearances, is this something that a toolmaker could do? Bearing in mind Iíve not fitted a spindle like that before, is it only worth getting a competent machine builder to do the job?

    I mean, I understand the process of setting the clearances and could probably get by, but considering the sensitivity of the spindle, is worth leaving it to someone else whoís done it before to show me?

    Also Iím surprised this j&s universal uses bronze bearings? Is there a possibility that it uses ball bearings?

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    Quote Originally Posted by Luke.kerbey View Post
    Also Iím surprised this j&s universal uses bronze bearings? Is there a possibility that it uses ball bearings?
    Tony's Old Lathe website says that J&S sold cylindrical grinders furnished with both hydrodynamic journal bearings and with ball bearings as a option. The ball bearing wheel heads were less expensive to make.

    The ball bearing wheel heads would have been grease lubricated and when worn would be very noisy. The spindle lockup as it approaches full speed is something that would occur in a journal bearing rather than a ball bearing.

    I wrote my earlier reply with the understanding that your employer does not want to spend any money on repair work. Once you start spending money the decision as to what to do becomes complicated. For most companies it makes more economic sense to buy a used grinder in good operating condition rather than spend money for major repair work on a older machine which may have hidden problems in addition to the spindle bearings.

    At the moment, the repair work consists of spindle disassembly, cleaning and flushing of the wheel head sump, making new gaskets, resurfacing of the spindle bearing seats and reassembly. Those are all straight forward if you have the maintenance manual in hand. The journal bearings or the spindle thrust bearing could be damaged if the disassembly sequence described in the maintenance manual is not followed.

    A second person to aid in the spindle work will make the job easier and faster. A tool and die maker will also have experience in resurfacing the bearing surfaces.

    The goal is to get the grinder running again rather than restore it to the factory specifications. There is no point in doing a complete wheel head rebuild if the machine ways are worn, the swivel table is rusty, the tail stock quill is loose, and the work head is misaligned with the tail stock. You just need to make the wheel head spindle good enough.

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    All I can start with is telling my boss that Iíve done my research and sought advice, give him my prognosis based on this research and give him the options of,

    - me stripping the spindle out and finding out the exactly collateral damage, possibly attempting to fix myself,

    - sending the wheel head off to be refurbished by a competent company,

    - buying a replacement machine or just wheel-head if possible.

    - outsource the necessary stuff for a couple years, look back after that time and calculate whether a replacement second hand machine would pay for it self in a reasonable time.


    The problem in decision making will be that the machine is used only on occasion, and with a push most of its work can be tickled on a surface grinder by making fixtures to bolt on to a harig grind all.
    While this grinder was down I had to grind a 166mm diameter ring to fit a bolster pocket, on a harig with a centre height of 75mm, it was a pain in the ass, took 2 hours to grind in microns per cut, but it worked and I got around using the broken cylindrical.


    I am thankful of your help, and I am leaning more towards the plain bearings being wrecked and possibly the lubrication system failure causing said bearing damage. I will post the outcome when I reach diagnosis. (May not be anytime soon, my boss takes his time on these things!)

    ** just in case, who in the uk can give me a scrap price for the broken machine?? 😂😂😂**

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    Default Sunnen OD honing stones and holders

    This is the link to the Sunnen OD honing web page if anyone else is interested in restoring a grinding spindle

    https://www.sunnen.com/graphics/asse...74c694ddff.pdf

    The stones with backing plates are inexpensive. The adjustable holder is something that can be improvised within your shop if only needed for a one time use.
    The information will also be useful if you need to explain to a engine shop what work needs to be done. The stones are available in up to 1200 grit.
    The device consists of a pair of V blocks held to the bearing seat with a precision C-clamp. One V-block or shoe is made up with a pair of honing stones. The opposite V-block serves as a guide and may be plastic or a low friction metal. The device is flooded with a low viscosity oil.

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    Default Jones and shipman universal grinder




    Hi guys, time for an update.
    The top cover has been removed to show the spindle housing, this version clearly has the bronze bearing type.

    As it stands the lubrication system is blocked somewhere. As best as I could photo graph it appears the internal primer is flaking away which is what Iím assuming is blocking the copper pipes. Possibly by my manger using hydraulic oil in place of spindle oil which incurred a chemical reaction with the primer?
    Please tell me if itís too far fetched?

    My manager is fixing this himself then will see if this is enough to stop the spindle stalling. And not attempt to look at the bearing faces as he doesnít want to upset the clearances unnecessarily.

    If this doesnít work then will remove the bearing cover to further investigate.


    Sent from my iPhone using Tapatalk

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    The wheelhead paint is not damaged by hydraulic fluid. It will lift off from the cast iron when exposed to water. The filter above the wheelhead serves two purposes. It collects grit and it stores water that has collected in the oil sump. If the filter is not drained on a regular basis it will no longer collect the water and you will see rust in the wheelhead.

    It is time to change the filter. Better yet, replace the filter housing with a modern 5 micron spin on filter. You are more likely to do routine filter replacement if it is cheap, easy and quick. The replacement inserts for the old style filter housings are expensive for some reason.

    Once the filter is replaced try running the spindle again and verify that the oil is returning to the left and right hand sumps rather than pouring out the spindle end caps.
    If there is no oil flowing out of the worm wheel oil pipe the problem is in the oil pump itself or it has a blocked inlet.

    The sight glass for the spindle incoming oil should show a steady stream when running. If not, tighten up the flow control nut on the worm wheel outlet to divert more of the oil to the bearings.

    Also try placing a dial indicator against the stationary spindle and giving it a radial push. Do this for both the left and right sides. That will give you an idea of how much radial clearance there is in the bearings. Then buy the maintenance manual and learn what the radial clearance should be.

    If this is your wheelhead illustrated on Andmar's website your spindle is NOT a pivoting shoe type and DOES use oil seals at the end caps.
    EIU Wheelhead - Jones & Shipman 1074 Spares | Andmar Machinery Services Ltd

    The repair work will not be as difficult as I first described.

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    Hi,

    The most we can do is clean the filter, at the moment, of it persists in the future we can change the filter if needs be, we can see there is a blockage between the pump to filter line or the filter to bearing lines as when we started the spindle the oil makes it through the line that lubricates the worm screw but nothing can be seen through the in line eye glass.

    I checked the spindle play on both ends and there was no clock Movement on a 2 micron DTI.
    So Iím guessing thatís either good as the spindle isnít worn or itís bad as the spindle clearance is blocked with crap from the filter, the actual spindle movement by hand seems okay to me, maybe a bit on the tighter side

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    Quote Originally Posted by Luke.kerbey View Post
    I checked the spindle play on both ends and there was no clock Movement on a 2 micron DTI. So Iím guessing thatís either good as the spindle isnít worn or itís bad as the spindle clearance is blocked with crap from the filter, the actual spindle movement by hand seems okay to me, maybe a bit on the tighter side
    My Studer RHU-450 universal cylindrical grinder has a similar bronze wheel bearing, also with a gear driven oil pump in the center of the housing. Lubricant is Mobil Velocite No 3, so light spindle oil. The instructions for adjusting the clearance of the bearing call for 50 microns of axial free play, which (because the bearing taper is 10:1) implies 5 microns of radial clearance for an oil film.

    I suspect that the spindle axial clearance on your machine is meant to be similar to my machine, which suggests that bearing surfaces on your machine are clogged.


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