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  1. #1
    Join Date
    Apr 2009
    Location
    Kingswood
    Posts
    789

    Default Sheraton 9 A 1167

    Sheraton 9A #1167 was purchased in 2007 and operated successfully for a couple of years.
    I read all the books and diligently kept a good supply of oil up to the headstock bearings.
    I taught myself machining on this lathe, corrected several problems and was getting good results.
    Then, it developed hot headstock bearings and the occasional seizing.

    An inspection revealed bad bearing surfaces with significant scouring and quantities of loose debris.
    The spindle runs directly in the CI housing, with helical grooves in the housing to distribute the oil.
    I formed the opinion that the debris had been flushed out by the oiling and was moving into jam-up positions.

    There was the prospect of significant difficult work to correct, so a replacement lathe was purchased.

    I enrolled in a TAFE course and eventually was able to use the cylindrical grinder and horizontal borer.
    The spindle was ground, the headstock bored out, bronze liner glue fitted and bored to suit the new spindle size.
    Then I got kicked out of TAFE !

    Years have passed, but now has come the time to get the old girl going again.

    The photo shows the headstock after slitting with a gap now of 2 mm.
    Measuring the chuck end, bore is 45.76 mm and spindle is 45.73 mm.
    They won't go together easily, and I have not tried to force it.

    Sheraton Headstock Slit compr.JPG

    Requesting comments on a couple of subjects:
    - what bore size should I have,
    - how to go about lapping the bores,
    - size of hole to drill through the bronze for the oil,
    - source for suitable oilers (I think 5/16" BSF),
    - advice on grooves in the bronze to distribute the oil.

    Keep well,
    John.

  2. #2
    Join Date
    Jun 2020
    Location
    Bacchus Marsh, victoria
    Posts
    25

    Default

    Quote Originally Posted by electrosteam View Post
    Sheraton 9A #1167 was purchased in 2007 and operated successfully for a couple of years.
    I read all the books and diligently kept a good supply of oil up to the headstock bearings.
    I taught myself machining on this lathe, corrected several problems and was getting good results.
    Then, it developed hot headstock bearings and the occasional seizing.

    An inspection revealed bad bearing surfaces with significant scouring and quantities of loose debris.
    The spindle runs directly in the CI housing, with helical grooves in the housing to distribute the oil.
    I formed the opinion that the debris had been flushed out by the oiling and was moving into jam-up positions.

    There was the prospect of significant difficult work to correct, so a replacement lathe was purchased.

    I enrolled in a TAFE course and eventually was able to use the cylindrical grinder and horizontal borer.
    The spindle was ground, the headstock bored out, bronze liner glue fitted and bored to suit the new spindle size.
    Then I got kicked out of TAFE !

    Years have passed, but now has come the time to get the old girl going again.

    The photo shows the headstock after slitting with a gap now of 2 mm.
    Measuring the chuck end, bore is 45.76 mm and spindle is 45.73 mm.
    They won't go together easily, and I have not tried to force it.

    Sheraton Headstock Slit compr.JPG

    Requesting comments on a couple of subjects:
    - what bore size should I have,
    - how to go about lapping the bores,
    - size of hole to drill through the bronze for the oil,
    - source for suitable oilers (I think 5/16" BSF),
    - advice on grooves in the bronze to distribute the oil.

    Keep well,
    John.

    My gut feeling is that the bores are not precisely aligned. It should be possible to fit each end of the shaft into each bearing to show that the shaft is a clearance fit. My feeling is that the shaft should be pushed into the bearings and let the shaft wear be used to 'run-in' the arrangement.
    With respect oilers, it is problematic whether you can get anything with BSF threads. I have used helicoils to make a tapped thread. Maybe replace the BSF threads by using a 5/16 UNF helicoil.
    I cant advise on grooves. maybe get a Dremel or such like and scratch some oil distribution grooves. They are not really all that critical.
    Hope this helps.

  3. #3
    Join Date
    Feb 2014
    Location
    Werribee, Melbourne
    Posts
    101

    Default

    I would think that the oilers are possibly 1/8" BSP. I have a mid '40's Macson which is another older Aussie made machine and it has 7 oilers that have a couple of different capacities but all of them have 1/8" BSP mounting threads.

    I would have a close look before reaching for the drill - 1/8" BSP should measure close to 0.343" ID and 28tpi.

    If you do have 1/8" BSP oiler threads then there are several options - I got a couple of flip-top 1/8" BSP from LPR Toolmakers (Victorian mob) for my old Senecca Falls machine (it is a flat-belt machine of similar configuration to your Sheraton -picture in my profile) and added a central pipe to make them a wicking set-up.
    They aren't the greatest thread fit but were reasonably cheap, available and do the job.
    https://www.lprtoolmakers.com.au/ste...-threaded-end/

    If you check eBay for 1/8" BSP oilers you will get a lot of choices (and some of them are not cheap). To get going I would say the LPR flip-top ones would be a reasonable start and probably locally available - this is what I ended up with after adding the central bit

    IMG_0852.jpg

  4. #4
    Join Date
    Jun 2020
    Location
    Bacchus Marsh, victoria
    Posts
    25

    Default

    Quote Originally Posted by Ray-s View Post
    I would think that the oilers are possibly 1/8" BSP. I have a mid '40's Macson which is another older Aussie made machine and it has 7 oilers that have a couple of different capacities but all of them have 1/8" BSP mounting threads.

    I would have a close look before reaching for the drill - 1/8" BSP should measure close to 0.343" ID and 28tpi.

    If you do have 1/8" BSP oiler threads then there are several options - I got a couple of flip-top 1/8" BSP from LPR Toolmakers (Victorian mob) for my old Senecca Falls machine (it is a flat-belt machine of similar configuration to your Sheraton -picture in my profile) and added a central pipe to make them a wicking set-up.
    They aren't the greatest thread fit but were reasonably cheap, available and do the job.
    https://www.lprtoolmakers.com.au/ste...-threaded-end/

    If you check eBay for 1/8" BSP oilers you will get a lot of choices (and some of them are not cheap). To get going I would say the LPR flip-top ones would be a reasonable start and probably locally available - this is what I ended up with after adding the central bit

    IMG_0852.jpg
    Ray suggests the oilers are 1/8 bsp. This size is about 3/8 inch diameter I think. I rather think you should precisely determine the actual thread.
    The Sheraton is based on the Southbend and I am not sure if the threads are generally UNC/UNF or Whitworth, but I am sure the chuck spindle is 1 1/2 BSF.
    I am working on a Premo ATM, and it is full of BSF and BA threads. The largest BA thread is 0BA and this is very close to 6mm metric. 2BA is about 3/16" and 2BA oilers are available from the UK.
    Hope this helps.

  5. #5
    Join Date
    Apr 2009
    Location
    Kingswood
    Posts
    789

    Default

    I have successfully lapped the spindle head end bore.
    Used a timber lap and kitchen cleaner in linseed oil.
    Only about 6 CNC cycles on the CNC mill +/- 47 mm at 100 mm/min with the lap at 400 RPM.

    Spindle, lubricated with linseed oil, enters bore completely.
    It really is a firm fit and I may have to repeat later.

    Now to get the spindle into the rear bearing.
    This may require a honing step.

    Lap was timber mounted on a M12 stud with a Dia 20 cylindrical nut at one end.
    Mounted on lathe in a Dia 20 mm collet and reduced to Dia 44.5 mm.

    The ER32 nut was reduced to Dia 43 mm so that it would enter the bore.
    (A difficult job requiring frequent freshening up of the brazed tungsten tool.)

    Photos show the lapping on the mill, and the fitting.

    Headstock Lap Mill compr.JPGHeadstock Spindle Inserted compr.JPG

    Keep well,
    John.

  6. #6
    Join Date
    Sep 2012
    Location
    North Yorkshire UK
    Posts
    4,119

    Default

    Hi John,

    You are going to have to leave a couple of thou for an oil film or its going to seize the spindle. A firm fit is fine for aligning the bores, but friction is going to heat up the bearings.

    As I said on HMEM I would get an adjustable reamer and ream the bores to suit. At least that way if they were a little tight, you could always take a fraction more out, and if you put oil grooves in them you are still going to have to clean the sharp edges off the grooves.
    Best Regards:
    Baron J.

  7. #7
    Join Date
    Apr 2009
    Location
    Kingswood
    Posts
    789

    Default

    The rear bearing was an exact fit, bore to shaft, so some work expected.
    Used the same approach, timber lap in the mill with Z-axis cycles programmed on the CNC.
    Worked for some time before I could achieve entry of the spindle.

    Then, very pleasingly, when I tried a dry (no lubricant) entry into both bearings - success.
    The alignment was excellent, fit very tight, but there.

    Headstock Spindle Home compr.JPG

    If I rotate the spindle a number of times, then remove it, I can see the localized contact rub marks in the bronze.
    I use a small buffing wheel, dia 30 mm x 5 mm thick impregnated with the lapping slurry, on the rub marks to reduce the contact.
    Expect some work now to get a reasonable operable fit.

    Once I think it operable, I will fit the shims and lubrication, then run for a few hours at low speed, with frequent check on temperature.

    The slitting saw was 2 mm, so the first trial shims will be 2.1 mm.
    The old ones were steel, so making them again in steel makes it easy to surface grind to thickness.

    Not yet resolved just where I will put the oil distribution grooves.

    Keep well,
    John.

  8. #8
    Join Date
    Dec 2011
    Location
    Sydney
    Posts
    371

    Default

    I'm wondering how you went finishing the bearing surfaces, and also have a question.
    Did you suceed in removing the bearing rub marks? If not, a small bearing scraper may be the go I think (been there, done that on the spindle bearings on an old IXL lathe).
    With a scraper you can easily take a skerrick off a localised spot without leaving any buffing abrasive in there.
    Can loan you a bearing scraper if you need one.

    Also I wish to lap the rough off a less than beautiful cast iron bore, looking for a few less hundredths, not looking for tenths, and hopefully without buying a bit of 55mm dia aluminium rod to make the lap, so your 'lapping with wood' approach might do the trick.
    What sort of wood did you use, and how did you set it up to be expanded as the lapping proceeds?

    Cheers,
    Bill

  9. #9
    Join Date
    Apr 2009
    Location
    Kingswood
    Posts
    789

    Default

    WCD, thanks for the comments.

    Not finished yet, but sizing is close.
    Last processing was a bit of spot buffing and some general lapping with a plastic self-springing holed lap.
    Not pushing hard with these approaches at the moment.

    Got a line on some scrapers to be acquired next week.
    Then, an interesting new phase of metal processing learning is expected.
    I will have the opportunity to review progress with some retired tool makers and TAFE teachers, and to practice scraping under their tuition.

    The timber laps I used were pine turned down to a 'firmish' fit without any expansion.
    Lap in the vertical mill, loading against the lap was achieved by hand pressure.
    As soon as entry was achieved, that method was terminated.
    Confident on where I am because double insertion was achieved without any forcing.

    Currently, the spindle fits tight, but rotatable.
    The bores have a high degree of smoothness, and contact areas are evenly distributed and polished.

    I can say that the self-springing plastic laps are amazing.
    Did not go far with this other than to demonstrate practicability.
    For the Dia 45 mm bore, a length of Dia 50 mm pipe, double slit at an angle to reduce diameter to fit.
    Then multiple holes drilled through to retain cutting compound.
    Definitely worth pursuing.

    Thanks for the offer of help.
    Got scrapers organized at the moment.
    Perhaps worth conversing by PM to discuss our jobs.

    Keep well,
    John.

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