harrison m300, spindle run out...bearings?

Go no further - including running the lathe under power - until you have resolved the issue with the rear bearing - that is most clearly wrong!

What sort of bearings are fitted in the rear end of the headstock - cylindrical roller bearings, needle roller or is it another taper roller bearing? If its a taper roller bearing and the rollers are appearing to not be pre-loaded then this can be rectified with whatever adjustment is provided- if they are cylindrical roller bearings or needle rollers and the rollers are moving in the cage then perhaps this is indicating wear. If you had a headstock cross section drawing you could upload a photo of this might help everybody with the diagnosis advice.

Neil.

Tony's lathe site declares that "The spindle, which runs in Gamet Super-precision opposed-thrust roller bearings."

So adjusting the end float might well cure things although there will likely be the usual problem of the bearing not wanting to move in response to the adjustment after this amount of time. Not withstanding that, I think that there has to be some damage to that rear bearing for the rollers to have that amount, and degree of freedom, to move as they are. The bearing cage should still support the rollers in their correct place and orientation, no matter how slack the bearing adjustment is so my money is still on a broken bearing cage.

We have a Harrison VS330 at work, which is similar size & vintage to an M300 (our machine is an '87).
While I can't guarantee it (can't find an M300 parts book online), I would expect the spindle bearing arrangement to be similar if not the same.

The VS330 has a Gamet 124070/124112xC front bearing and a Gamet 110055/110100C rear bearing according to the parts book. Hope these are OK, as Simply Bearings list the front bearing at £325.62 & the rear at £271.07 - both plus Vat.

The VS330 manual spindle preload setting proceedure is to check the drag torque on the spindle after running at 800 rpm for 10 minutes.

The correct torque is given as 0.9/1.1Nm (8/10 inch pounds), checked by wrapping a cord 3 times around the chuck & attatching a light spring balance to the free end of the cord. Gently tension the spring balance until the spindle just starts to turn & maintain the rotation - read off the value of the spring balance. Example given is using a 160mm dia. chuck, the balance reading should be 1.14/1.38 kg (2.5/3 lbs).

Bearing adjustment is via a nut under the rear bearing cover. Remove the end drive guard, changewheels, swing frame & rear bearing cover. Release locking screw in the adjusting nut. Using pin spanner provided with lathe, adjust the nut clockwise to increase preload. As overtightening will shorten bearing life, work in small (3mm at nut periphery) increments. After each incremental adjustment run spindle for a few minutes & re-check drag torque.

Loose rollers suggest adjustment is required - all the rollers should rotate when the spindle is rotated.

HTH

Nigel B

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

Easiest to upload it to You-tube then put the URL in a post.

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

**LINK**

90 degree to chuck mount

**LINK**

centre of spindle

**LINK**

close to rear bearing

**LINK**

90 degrees at end of spindle

**LINK**

traversing along parallel bar

**LINK**

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...

I'm afraid it doesn't tell you anything of the sort. We're talking microns of clearance, so even a small temperature difference is important. Running my M300 for 10 minutes or so reduced axial play to undetectable, even though the front cover, by the Camlock fitting, still felt cold. When I've run the lathe for some time that cover is warm to the touch, probably around 30/40 degrees. In order to make comparisons with the manual you need to follow the same procedure, although the temperature of the bearings will have a bigger effect than the diameter of the chuck. Of course a bigger diameter means more torque for a given force.

Andrew

Interesting ,particularly the cracked bearing cage on you tube, Trouble is one never knows with used lathes their life history,there are a lot of idiots about who attempt to adjust mechanical items without the handbook and make things worse as they do not attempt to look at the cosequences of "if I tighten this nut will it affect anything else ?''So I still think a complete strip down is essential. The only other snag is to consider is the cost of one or both Gamet bearings more than the lathes value. ? Has anyone tried o replace the Gament bearings with sav top Quality timkens or are Gamet bearings made so they cannot be replaced with cheaper bearings,because does the averager modeller really need super precision bearings,I believe Boxfords use top grade Timkens

Hi Sebastian, I wouldn't think the runout on the middle of the spindle is anything to worry about, as it doesn't appear to run on anything and is probably the diameter of the steel used before all the journals were made and the gears each side appear to be running true. Don't get to bothered about the movement of the roller cage, that must not bind on any part of the rolling elements, as the oil will have to be able to pass in and out during rotation. The cage only keeps the rollers an equal distance apart. I would say your Bronze particles in the oil have come from the bushes you mention, and may not be of any concern, depending on the quantity, might just be time to change the oil.

Regards Nick.

Edited By Nicholas Farr on 19/12/2018 20:52:40

The videos certainly tell a lot more than the prior words convey as the rollers seem to be captured correctly in the bearing cage. The vision I had conjured up from your description of the rollers falling down when the cage rotates past 45 degrees was akin to the cage being non-existent. "Some of them actually drop just through gravity as they rotate past the TDC position through 45 degrees into 90 degrees rotation..." Perhaps my over active imagination! Goes to show the value of pictures cf. words.

Edited By Neil Greenaway on 19/12/2018 21:51:14

Edited By Neil Greenaway on 19/12/2018 21:52:44

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

Hi

From the video It appears that the "bearing play" is the bearing cage moving, the actual rollers appear to be stationary.

To measure the radial run out I regard any non mating outside surface on the spindle as suspect, only the spindle inside and outside tapers and the chuck mounting face (if they are in good order and have not been worked on) can give a reasonable indication.

If it appears that the mating faces have been worked on I would set a known precision ground bar say 400mm long by at least 40mm diameter in the 4 jaw chuck and after setting it dead true I would check that for run out near the chuck; if it can be set dead true it would make me wonder maybe the bearings are OK, at least without a load? The final test would be to apply a load to the end of the bar to see if there is play in the bearings under load. by using a known roundness bar you have eliminated errors caused by worn surfaces on the spindle nose.

Once the above test has been set up you can place a insert a reasonably well fitted bar in the back end of the spindle and apply radial pressure while checking for errors at the chuck end, you may need a helper.

Hope this helps, it should give a better indication of current condition..

Hi Sebastian, I had the same vision as Swarf Maker about your rollers falling down from your written description. What you need to realise is that when your spindle is in use, the hydraulic action of the oil will keep all the clearances between the cage and the rollers and between the cage and the inner and outer bearing rings and also the rollers will not fall as they do when turning by hand. Car wheel bearings usually run in grease, which will not allow the same kind of movement when turning by hand, as it doesn't drain away from the bearings like oil does.

Regards Nick.

Here we go then Sebastian; Having looked at your videos I haven't seen anything that would give me cause for concern. That is it would be without knowledge of the problems that you have been experiencing. Your manipulation of the bearing cage shows nothing untoward and what I had interpreted as rollers flopping around is clearly nothing of the sort. You are having to apply some force to skew them. As that test was done with everything cold then the expected end float may well be commensurate with that degree of available movement.

What needs to happen is a re-examination of the salient facts and first amongst those is the degree of eccentricity that you identify as randomly and periodically occurs. You have described it as visible on both the work piece and the chucks I believe (too late at night to re-read the whole thread). We really need some numbers for that.

The next crucial point to examine is the running temperature in the vicinity of the front bearing. From your description and the helpful input from other forum members, it would appear that your spindle is getting much hotter than anybody elses. That heat can only be coming from the dissipation of energy. Discussion has tended toward the bearing pre-load being too low as a consequence of our interpretation of your descriptions with respect to the rear bearing, but that is inconsistent with a hot spindle which is much more likely to occur if the pre-load is too high. So do the torque tests as already identified and lets see what that tells us.

As all of the measurements that you have taken are essentially nominal we are left with only subjective assesments to deal with viz. hot spindle, visible wobble. Difficult to ensure that we are working to the same criteria on that basis as witnessed by the previous mis-understandings of the symptoms.

Perhaps the best thing is for you to put it in a large 'jiffy' bag and post it up to me for a good looking at!

I don't think there is much point in doing anything or speculating about anything until the headstock bearings have been correctly adjusted exactly as per the manual instructions. Basic troubleshooting 101: Eliminate the simple stuff first.

Edited By Hopper on 20/12/2018 00:40:05

Reading the posts I've gone from 'bearing problem unlikely', to 'bearings guilty' to 'case against bearings is unproven'. I think the wobble is down to the difficulty of describing in text what's going on.

Sebastian's videos are more helpful. They suggest to me that there's not much wrong with the lathe in so far as the tests don't find anything to account for the symptoms. What we haven't seen though is a clip of the lathe misbehaving during a cut. Sebastian: now you've cracked YouTube could you film the malfunction please?

I guess there aren't any Harrison experts near Exmouth who could take a look.

Dave

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