Sheraton 9 A 1167

[electrosteam]

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.

389027

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.

[rumpfy]

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.

389027

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.

[Ray-s]

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/steel-oil-cup-2-to-1-4-od-head-bsp-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

389079

[rumpfy]

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/steel-oil-cup-2-to-1-4-od-head-bsp-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

389079

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.

[electrosteam]

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.

389139389140

Keep well,
John.

[BaronJ]

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.

[electrosteam]

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.

389240

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.

[WCD]

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

[electrosteam]

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.

[electrosteam]

Got the scrapers, and had an interesting couple of weeks of sporadic work.
Very interesting, fascinating to see the fit slowly getting better.
The front main bearing is nearly perfect with the spotting, the rear is a bit patchy but I will run it that way and see how it performs.

Longitudinal groove:
Made a 3 mm semi-circular single-lip cutter out of a 6 mm HSS rod 300 mm long.
Mounted that in an ER16 collet in a ER32 collet at 20 degrees from vertical in the turret mill.
The stick-out was necessary to reach all the way into the bearing.
Headstock vertical on the table with the cutter opposite the oil entry hole. the bottom on the bearing when installed.
Single-line Z-axis instructions on the CNC sent the cutter alternately jogging to the bottom of the groove, then ramping in 0.05 mm vertically to the top of the groove.
Stopped when the groove looked good.
Swapped ends and repeated for the rear bearing.

389840

Circumferential groove:
Made a very short boring bar bit from some 1/8" square HSS, shaped with a half-round cutting edge.
Mounted the headstock on a rotary table and set the bit level with the oil entry hole.
Touched-off, then rotated the headstock until bit in the oil groove, advance the cut and rotate table back to the oil hole.
Repeat until the new groove matched the first.

389841

The finished result for the main bearing:

389842

But:
I have had advice that the longitudinal oil grooves would be better at the top of the bearings.
Should I return to the mill and add grooves at the top ?

Keep well,
John.

[BaronJ]

Hi John,


I have had advice that the longitudinal oil grooves would be better at the top of the bearings.
Should I return to the mill and add grooves at the top ?

It probably would make little difference ! The way I see it, an oil groove at the top so oil will migrate round the bearing even when the shaft is stationary. An oil groove at the bottom will act as a reservoir so oil will get carried round as the shaft turns. Having both almost guarantees that the bearing will be well lubricated.

[Abratool]

Hi John,



It probably would make little difference ! The way I see it, an oil groove at the top so oil will migrate round the bearing even when the shaft is stationary. An oil groove at the bottom will act as a reservoir so oil will get carried round as the shaft turns. Having both almost guarantees that the bearing will be well lubricated.

I recall reading about oil grooves in Machinerys Handbook & just looked it up.
There is a detailed description of oil grooves in that reference book.
Bruce

[electrosteam]

Progress.

Cleared-out a lot of rubbish from the workshop, had a 12 mm ply ceiling installed, and the stripped-down Sheraton bed/stand moved to the roller door.
Now comes the re-assembly.
The original belt was cut to remove it and long-lost.

What size belt do I need ?

As the lathe may end up in the hands of a good friend, would it be better for him if I use a multi-segment belt ?
If so, any suggested sources ?

As there is no lighting yet in the workshop, photos will come 'soon'.

Keep well.
John.

[kafie1980]

I am not sure which size link belt will fit the Sheraton but Carbatec sells a link belt that works for most drill presses and lathes requiring the 1/2” wide size:

https://www.carbatec.com.au/rockler-adjustable-link-belt-vibration-reduction

They are not cheap although ebay and Aliexpress may offer alternatives.

[Bigcam]

Mine runs a pair of B-43 belts.

[electrosteam]

Bigcam,

Thanks for the belt type, but I cannot read the lengths in the photo.
Could you please check the lengths for me ?

It has been 10 years since I dismantled the lathe, so everything is new again for me !
I hope I don't fall in love with it a second time as I really don't need two lathes.

Thanks, John,

[pipeclay]

2 x B43

[electrosteam]

pipeclay and Bigcam,

Thanks for the details and confirmation, you can see how long it is since I considered belt details.

A special invitation for you to come to lunch next Tuesday.

John.

[Darryn]

Progress.

Cleared-out a lot of rubbish from the workshop, had a 12 mm ply ceiling installed, and the stripped-down Sheraton bed/stand moved to the roller door.
Now comes the re-assembly.
The original belt was cut to remove it and long-lost.

What size belt do I need ?

As the lathe may end up in the hands of a good friend, would it be better for him if I use a multi-segment belt ?
If so, any suggested sources ?

As there is no lighting yet in the workshop, photos will come 'soon'.

Keep well.
John.
Sorry I haven't posted on this forum in a long time but I may have some spare B section link belting that came with a Sheraton I bought a while ago. My shed is a mess but I can plan an archaeology dig on the weekend and let you know.

[electrosteam]

Darryn,
Thanks for the kind offer, I will PM you.

Assembly is progressing with the spindle assembly a very nice fit in the headstock.
I am using ISO 68 for lubrication.

But, before I attempt to spin the spindle up I need to do something about the headstock shims.
They are currently ground steel of about 1.8 mm thick.
I know the originals were aluminium.

As I see it, the risk with the steel is them moving out of position and rubbing on the spindle.
This may be particularly a problem with the initial running as I experiment with shim thickness and closure bolt tightness.

My research says that grinding aluminium is doable, and I have a surface grinder.

Suggestions welcomed on how to achieve acceptable shims.

Keep well,
John.

[Darryn]

The archaeology dig was slow but successful! The belt from my lathe is in the middle, you are welcome to the one that's the longest.
403959

[electrosteam]

Thanks Darryn for the belt, I will put it to good use.

Photo shows the very rough setup to run the bearings.
Running at about 200 RPM.
The DC motor is 300 W, 440 RPM at 24 Vdc.

Start conditions: 4.4 A at 10.8 Vdc.
After 14 hours: 2.0 A at 10.5 Vdc (the battery charger was losing the race !).
Bearings were virtually at room temperature.

The run was broken up into 1 to 2 h sessions.
At the start of each session the current was higher, then dropped off.
As oil was added at random, the current would increase by about 10 %, then settle back down.

Very interesting.
Note that 2.0 x 10.5 is only 21 W of electrical power (and the measurements were confirmed).
As the DC motor was warming up, the actual spindle power was less.

The new belt can be seen hanging on a pulley in the back of the photo.
That will now be installed and the spindle run by the AC lathe motor (if it still works !).

404313

Keep well,
John.

[electrosteam]

Got the belt on, and ran the spindle progressively up to max speed.
Then multiple runs at max speed for progressively longer periods.
Last run was 60 minutes in 23 degrees ambient.
The bearings ended up quite warm, but far from hot.

One small problem, the thickness of the belt makes it a tight fit between the pulley and housing as speed is changed.
For anyone reading this, I think the modern tab/slot non-rivet link belt would be better in this regard,
But, the rivetted links do run nicely, it just purrs.

John.

[Michael G]

Probably too late, but -


I am using ISO 68 for lubrication.

I don't have a solid bearing lathe, but I had to get something thinner for the solid bearings on my surface grinder. It may be worthwhile investigating oil grades, as I am not sure (although I'm no expert) that the lubrication you are supplying will work well enough to flush while maintaining an oil film.


My research says that grinding aluminium is doable, and I have a surface grinder.

You can, but the problem with grinding Al is that it loads up the wheel, which can then cause problems with overheating and (worse case) wheel spalling. Holding it to the chuck is another issue. We used to use a vacuum table, but if you are going to go to the trouble of making one of those, you could also then grind stainless.

Michael

[electrosteam]

Thanks Michael for the comments.
At the rate the bearings pass the ISO 68 oil, I don't think I need anything thinner.
Your comments on the shims noted.

Lathe is shaking down nicely.
But now I need help with a mystery.

404522

The photo shows the set of change gears that achieve the nameplate imperial threads on this lathe.
Stud 20, floating intermediate 127, gearbox input 56.
This was tested to get 8 tpi.

But, I cannot fit the cast swing door.
I have a support arm that clamps to the rear prismatic way.
The door has a pin that engages a hole at the end of the arm.
All looks good, but the door contacts the 127 gear.

Perhaps the door never closed.
It is 14 years since I operated this lathe, and the memory fades.

The intermediate is compounded with 100, the combination having a bronze bush that rotates on the banjo idler shaft.
None of the other available gears have a bronze bush, they are all keyed.
There is a table on the door depicting gear arrangements with the 100 that achieve a good range of metric threads.

After 'fiddling' around for some time, there seems to be some possibilities for lost items:
(a) a smaller intermediate with a bronze bush,
(b) an alternative banjo idler shaft suitable for keyed gears,
(c) an additional arm mounted between the support arm and the door.

I don't believe I have lost any items in storage.
But loose items could have been missed when I picked up the lathe from the seller.

Could someone with an identical lathe please tell what me their solution is ?

Keep well,
John.

[electrosteam]

Searching shows that the door not closing on the 127 gear was a recognized problem on South Bend lathes !

As I intend selling this lathe in the New Year, I am not inclined to do anything drastic.
But a smaller intermediate gear is still an attractive option to make the package neat, and safe, for inspection.

The centre-centre of Stud to Gearbox is 5 1/4".
The normal arrangement for the nameplate threads is 20 Stud / 56 Gearbox.
The largest gear I have is 57, and it does not span the gap.

Calculations shows 60 teeth on the intermediate would span the gap.

So, if anyone has a spare Hercus/Sheraton gear of 60 T or greater, I would interested in acquiring it.
My records show that a 68 is necessary for 17 TPI, so that one is attractive.

Keep well,
John.

[kafie1980]

A workaround to the door closing problem by model engineers on their lathes was to make a 127 tooth gear and the paired gear with a smaller diametrial pitch such that the resulting 127 tooth gear was no larger than the biggest supplied change gear.

[electrosteam]

Got a Hercus 80 T idler gear at Mick Moyles.
This selected on basis it had the extended shoulder and oiling holes showing it was meant to rotate on a shaft.
Although a bit rusty, it had good teeth.

Cleaned gear in citric acid for 4 hours.
Made a fixture for the lathe, and proceeded to bore it out.
Unfortunately, the shoulder turned out to be steel pressed into the C.I. gear, that could not accept the required diameter of the bronze bush.

Then the bronze bush was Loctited into the gear.

Job finished fine, and the photo shows the bushed gear before removal from the lathe.
It fits on the lathe perfectly, and the door closes.

404586

Only thing to be done on the lathe now is to finalize the headstock bearing shims.
Time to get the surface grinder fired up.

John

[nadroj]

This might be appalling to hear, but I used newspaper as temporary shims on my Hercus 9 headstock.
It has been left like that for many years with no problems.

It was a quality broadsheet newspaper, not a horrid tabloid. :)

[BaronJ]

Hi Jordan, Guys,

I often use 120 grm paper for shims, gaskets and similar. For the gaskets I oil them so that I get a gas tight seal, particularly if using two or more layers of paper. I've also used 250 grm card, but that doesn't compress as easily.