Member postings for Sebastian York

Good afternoon gents.

Firstly I will apologise if my wording was more dramatic than what I can see happening...regards the rollers when I rotate the spindle I can see them shift their axis, and some actually moved about just under the force of gravity within their respective cage location as I rotated the spindle...almost as if they are not being supported fully between the inner and outer race. Inner cage seems intact...but cant help but think there should be enough contact between the races and all the rollers to prevent them from actually moving in any other way than rotation...

Also all the videos have been made following the application of the artificial preload supplied by the tailstock...prior to this the dti when engaged on the nose of the spindle was quite literally all over the place, but with no distinct high spot. Rotating by hand would have no effect on needle movement, but when at speed was throwing about...since doing as was suggested with the tailstock, even under high rpm the needle hovers quite happily around 0 run out.

Today I did the following...

From cold, ran at 800rpm for 10 mins with no chuck fitted. Power off and fitted 200m 3jaw...cord wrapped round 3 times to calibrated spring balance...

Took just under 2lbs of pressure to rotate chuck...

Left the machine for 30 mins to cool down and did the same again...same reading...

Now admittedly this is a 200mm not 160mm chuck as the instructions state...but would people agree that is potentially a little low? If so is it worth nipping up to bring the force required up to say 2-2.5lbs...

If it is on the low side...could it be something so simple as the preload nut just undoing very slightly and allowing the spindle to just creep forward a small amount...resulting in the symptoms that I have witnessed over the last few months...one minute spinning true, then just edging forward due to inertia of rotation and giving me the wobble/run out I have witnessed?

Also stripped the drive belts off...they seem OK, but for the sake of a few quid Ill get new ones...Will go on a limb here and suggest that a trip to the local motor factors will supply a variety of suitable V belts, as its not likely to be some fancy dancy belt like the bearings...but just a plain v drive belt...

Ran the motor without any load...no strange noises that I can hear...

Rotating the drive spindle in the headstock there is a faint clunk...so potentially the dull thud I can hear when the lathe is spinning...but again no tight spots or wobble here.

Cheers gents...

yorkierm

Evening gents.

Tomorrow I will refit the bearing cover and run her for 10 mins and re test with the spring balance...

Swarf maker...glad the videos show things more clearly...sorry if my words made it seem like the cage had fully disintegrated...but when you rotate the spindle you can see some of the rollers move their axial position in relation to the races...and I cant help but think that I should not be able to freely move the cage that much nor move the rollers between the races...To me it does seem that the preload isnt right...but will re investigate the movement after running it up as described...

Only going on the principal of a car wheel bearing...but if there were play in the bearing like I can see in the rear bearing here...I would say it needs tightening or replacing...

Where do your thoughts lie now?

Also as I cannot see any of the front bearing without a full strip I cant see if its doing the same as the rear...so unsure what my next step should be...

regards

Edited By Sebastian York on 19/12/2018 21:56:49

OK then...some short (20 second roughly) clips.

Whats the general thoughts gents? all very much appreciated.

parallel to spindle bore

**LINK**

90 degrees on spindle nose

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90 degree to chuck mount

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centre of spindle

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close to rear bearing

**LINK**

90 degrees at end of spindle

**LINK**

traversing along parallel bar

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rotation at end of parallel bar

**LINK**

BEARING PLAY...these are probably the tell tale ones...

**LINK**

**LINK**

**LINK**

That turned out to be a lot less painful than I imagined...and I now have a you tube channel

hope these help...

Cheers for all your help gentleman.

They are Gamet opposed taper roller bearings, as named by Nigel B (same part numbers in my manual).

Have made short videos of all I previously posted...but this is where technology beats me...I cannot fathom out how to share them on here!

I'm currently feeling Swarf makers theory on a broken cage may be right... as said I can actually move the cage of the rear bearing between my fingers. This is just the rear as cannot get to the front without pulling at all apart...

Not wanting to power it up...I tried the torque test as described...admittedly with a 200mm chuck...and without running the machine...but only took just over 1lbs of force to rotate the chuck...so potentially it is loose on the preload...

I also don't have the adjusting wrench yet...so either need to make or buy one.

If anyone knows how to...or is willing to post the videos for me...I can show clearer the state of things...

regards

Yorkierm

The latest:

All measurements taken with a calibrated 0.01mm Oxford dti (is this accurate enough or so I need to dig out the 0.001mm?)

Lathe and bearings cold.

Starting from the front, having supplied artificial preload from the tailstock with a revolving centre:

Dti at 90 degrees to spindle, on very tip of spindle nose, no real measureable run out...needle hovers over 0 line.

Dti at 90 degrees to spindle, on camlock mounting diamete, no real measurable run out...needle hovers over 0 line.

Dti parallel to spindle bore, again, no measureable run out.

Fine needle movement is attributed to surface finish.

Very centre of spindle as previously said has eccentricity of 0.14mm, but this is attributed to the gearing splined onto the shaft...it cannot bend in the middle right?

Having removed the rear bearing cover, and mounting the dti as close to the bearing as is possible, again there is no real measureable run out, needle hovers over the 0 line within 0.01mm. This again is attributed to surface finish.

At the very very end of the spindle there is eccentricity of 0.01-0.015mm. As the spindle looks to only be turned, and not ground finished, I assume this to be just manufacturing tolerances, but would welcome another opinion.

With a no 3 morse taper parallel bar mounted into a 3-5 and then into the spindle bore and tapped into place with a nylon mallet, the tool post runs true to the bar, 0 measureable deflection, needle hovers over the 0 line. Likewise, when measured up close to the spindle 0 run out, when measured at the very tip of the bar, a very small amount of run out, but a few gentle taps with the nylon got it pretty much bang on to 0...

Frustratingly removing the tailstock preload did not allow the spindle to relax, so currently still measuring as I have said...

With all that said, I am 99.99% certain that the spindle is not distorted. Other opinions would again be greatly appreciated.

Nigel has mentioned that some dealers load by stroping around the chuck. Ironically this was exactly how mine was loaded many years ago. Remember distinctly as thought at the time, that cannot be right, or why would they machine a purpose built threaded hole into the bed for a lifting eye...but at the time said nothing...that will not be the case ever again...

Bearing wise, and this is where I think I may have seen issues...

Looking into the rear bearing the needles are hollow, you can actually move the inner race between fingers...and when rotating the spindle you can see the needles rotate, and even move position...ie shift there axis...by inserting a drift into the bore of the needles it is possible to wiggle them left and right very very easily...I don't think thats right. Some of them actually drop just through gravity as they rotate past the TDC position through 45 degrees into 90 degrees rotation...so I am going out on a limb saying that the preload is way off...even though I cannot hear or feel anything wrong when turning the spindle. The heat being generated is possibly down to the front bearing having to have had to work a lot harder to remain concentric, which has led to premature wear.

I am going to endeavour this evening to take some footage of all said above to post for better passage of information...as pictures paint a thousand words.

As for the bronze looking bits in the oil...I cannot see any where they may have come from...but on the exploded diagram I have from a downloaded manual, there are some bushes on some of the gear shafts, which may well be bronze material but hidden from view till stripped out...Looked for evidence of contamination of the rear bearing but cannot see if any of this has made its way into the rear one to cause damage.

The saga continues...

As said, anyone near Exmouth on here that knows more than me?

Hi Neil.

No pics taken yet, but as am currently seriously considering a full strip and clean I may make a photo diary...perhaps should have done it with the chucks as they were very dirty inside...with a layer of surface rust...and are now nice and clean...

From my initial inspection there are no pre-load springs or nuts. This is backed up from the exploded parts diagram in the manual...it looks like the races front and rear press in, and preload is adjusted by by a nut at the rear of the spindle.

My concern about it getting hot was if I had introduced too much force onto the front face of the spindle in order to remove the run out...but once the revolving centre was withdrawn the spindle continued to spin true...

Oil delivery is simply by splash...hits the roof of the headstock and is gravity fed down to the bearing races.

Addition of forced oil circulation may be a consideration...along with the magnet and maybe a gauze filter...

Tomorrow I will also tap my parallel bar into the spindle to see how true that happens to be...but at the moment I am feeling that its a combination of lack of use setting the belts, old oil and just being sat, and the spindle having gone very slightly loose, as I cant hear any bad noises...or feel any roughness...only thing is how hot the spindle got...

Incidentally...if I do opt for a full restore...whats the preferred method of paint removal...sandblast with vital areas protected with anti blast tape...or acid dipping?

Incidentally anyone with far more experience of these things live anywhere near Exmouth?

Tonights update on investigations...

Had the top off the headstock. Oilways clear and no visible gumming. Lots of tiny phoshpur bronze looking glittery bits rested in the oilways, but cannot ascertain where they came from...all gear teeth intact and no visible damage to any component. I expected to see small filings as in most gearboxes. May pay to put a magnet in in there somwhere as a collector for any steel that finds its way in...In neutral the bearings can be heard rotating, but no rattle or tight spots...

Loaded the headstock spindle from the front with a revolving centre in the tailstock, and with a calibrated 0.01mm dti mounted on a magnetic base directly on the headstock ( to eliminate the risk of the saddle being a contributing factor) and with the nose of the dti on the smoothest part of the spindle I could find...was able to remove the run out. Even at 2500rpm the needle hovers around 0...so within 0.01mm run out...will assume its more of the surface finish on the spindle than actual runout as when rotating by hand with neutral selected...0 measurable run out with a 0.01 dti.

With the top off exposing the gear train, and the dti engaging the approx centre of the spindle, there is a eccentricity of 0.14mm rise/fall...which I attribute more to the gears that are splined onto the shaft rather than a distortion, as I very much doubt it'd bend in the middle when supported at both ends...

Changewheel end there is an eccentricity run out of just about 0.02mm,

So from what I can fathom the spindle is not rotating true in the headstock...and is spinning at a very slight (0.02mm ish) angle.

So...if the machine has taken a topple at some stage, could this be enough to knock the bearings off centre? Are there any other options that could cause a spindle to either distort or shift the bearing seat to run eccentrically?

On the M300 is the spindle adjustable for eccentricity?

Did however notice that the spindle got very warm, almost to warm to hold for extended period, while the rest of the headstock was at a comfortable temperature.

To much pre-load on the bearings causing the whole lot to get hot quickly? or possibly inadequate lubrication keeping them cool?

Other tests:

dti mounted on the rear of the saddle with the tip bearing on the V and there is no crabbing/movement of the needle over the length of saddle travel.

Still a lot of vibration, so next task is to remove the belts, check the motor for play and ensure all pullys are properly aligned.

Edited By Sebastian York on 18/12/2018 14:09:43

Nick,

Thats correct, turn the OD, then for some reason will just start to visibly run out...so goes from spinning perfectly true, to not doing so...when it happens do all the obvious checks, tight jaws, chuck tight on camlocks etc...but thus far have not encountered a solution...I also cannot be sure if its the whole chuck running out, or just the workpiece, but as I cant find anything loose when I check...so I assume its the whole lot shifts...

Today have rebuilt the 3 and 4 jaws, so they are clean, debris free and re lubricated...both work well and close to centre with no issues...but as for balance...how would I check for that?

Like I say I really don't think the spindle is distorted, as it will spin true, and turn a uniform dia...but the vibrations felt through the machine may be what is effecting things.

Start at the bottom and work up as they say. Will order new belts to see if they are setting up bad vibes... run the motor without belts fitted and see how she sounds, and move up to the headstock and see if there are any damaged gears inside...

I'm very much hoping, and thinking now, it is just a case of been sat for many years in my parents garage unused, and is just in need of some tlc. But if the worst is that the bearings are gone least its repairable...my fear now is that more serious damage was caused if it did indeed fall over...but as said, I honestly don't think that is the case...and with a good bedway, the machine should be repairable to a high standard.

The fibre change wheels are in good order. Only one is slightly damaged on just one tooth...and that's only the very corner so will easily clean up. so they are not an issue.

I'm happy to turn this into a project to get right, but if something is worth doing, do it right once...I'm in no hurry to get it right, and like the learning, but don't want to be polishing a turd...as money doesn't allow for that...bottom line I want a machine I know is accurate and dependable.

Good morning gentlemen.

When I stopped using it years ago due to work and life taking over it was, from memory absolutely fine...but then I was also far less knowledgable / experienced than I am now...and even now I am still a very much a novice...

Tried with a variety of materials, and different cutting tools, tipped and HSS...

I will continue to investigate all avenues as described here...will also order some new belts and fit them. Tension wise currently they are free to turn through 90 degrees...is this either too tight or loose? lathe spins up freely and there is no belt slip...and I can feel no tightness any where in its rotation.

I cannot see any further damage to the machine...but it has been repainted during its regrind...so this would likely hide any scuff marks...no other damage visible on the machines other hand wheels. As the saddle run on the "V's" would it be able to crab at all since the regrind?

my use of the machine was, and is very minimal, but I don't know its history...or how it was used/treated prior to y ownership

When the bedways were re-done the lathe was reassembled by the guys who did the grind...cant remember the name but it was in Nuneaton somewhere...bronze bearing strip added to the Gib strip so thats all been done too...and they indicated no hint of any problems when I collected it...very little play in the compound or cross slide...

As for a bent spindle...how likely/hard is it to do such a thing? sounds very expensive and alarming! How often does this happen? and most importantly how would one measure for such eventuality? I don't think this is the case with me admittedly, as it spin true, then suddenly induces a visible run out...as if when the bearings get warm they move...

By way of example over the weekend I was turning a piece of stainless to 35mm OD, and bore dia of 28mm...3 jaw chuck...machine had been running for 30mins plus on and off so was warm, but not excessively hot...all was well, then within a few fine cuts went from spinning true, to a very visible run out wobble...checked all the obvious again such as chuck tightness, mounting etc...this happens regularly, and not just a one off...this is what initially led me to think bearing issue...that and I get a chattery finish...

As I want this to be right, I am edging towards making the lathe a little project first, strip and rebuild to get it perfect, and in doing so I will learn all about it...and once all is clean, burrs removed etc then I should be able to fully set up a very accurate machine as I know the beds good the rest should just be a case of clean and adjust...as long as the spindle isn't bent....

Thank you again for all input.

Thank you for all the input so far gentleman.

Its not a gap bed so that eliminates that possibility.

I had the bedways ground as I had the money, and wanted to be certain they were good...After purchase I noticed some damage to parts of the machine (main traversing handwheel on the saddle has been damaged and welded back on by its previous owner, not sure if the machine previously took a fall or was seriously knocked into, but was enough to smash the webs holding the handwheel together...)

Running the machine with a chuck (any chuck) fitted there is a pronounced vibration through the whole machine, but is not noticeable when running without anything fitted. CamLocks are adjusted evenly. Have adjusted the drive belts. Head is tight on the bed and doesn't move.

Lathe was stored in a garage.

With a 0.01mm dti mounted on the cross side, and the nose bearing on the spindle, there is no readable end float...however when holding the spindle at either end and pushing/pulling, it is possible to read between 0.01 and 0.02mm lateral movement...so far have not been able to find my 0.001mm dti to fully test the endfloat.

When cutting the following happens...

On fine cuts, lines are visible and surface finish is poor, but it is possible to turn a true straight diameter (2" bar held in 3 jaw chuck approx 9in long)...but by traversing the saddle back along the workpiece(away from the headstock) the tool continues to cut, as if the workpiece isn't on the same axis as the cut towards the headstock...surface finish improves and lines less visible with a heavier cut, but then it cuts a taper...and again, if you traverse away from the headstock, the tool re engages with the workpiece...

I sincerely hope its not the very very expensive bearings...but the lateral movement is concerning me...

added...

the vibrations increase with rpm...the faster the gear, the more noticable...

yorkierm

Edited By Sebastian York on 17/12/2018 16:54:37

Good evening all.

Can anyone offer some advice re my M300 and spindle run out/bearings...

Owned it for several years now and had the bedways ground about 11 years ago...all seemed well...but its been in store for the last 7 as not been in a position to use it. its not a hard used machine.

Recently got it back up and running, and initially had some trouble getting a good surface finish...lines in the workpiece and general roughness...

levelled the taper out by adjusting the feet so turns true...but just cannot get the finish right...and will not hold its trueness.

run out seems to get more as the lathe speed increases...and periodically (with 3 jaw chuck) will just suddenly start to wobble...meaning work that was true as had all been done in the same chuck, suddenly starts to visibly wobble...

even a struggle to dial anything in using a 4 jaw...and will suddenly spin out of true

cant feel any movement, or produce a noticable reading on the dti... but is it possible that the bearings are either loose, or damaged?

thank you for any input

yorkierm

hi guys.

new guy saying hello, joined to gleam technical info and knowledge from all, and maybe share some if I can.

happy engineering all

yorkierm