harrison m300, spindle run out…bearings?

[Nigel McBurney 1Participant @nigelmcburney1]

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

[Nicholas FarrParticipant @nicholasfarr14254]

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

[Swarf MakerParticipant @swarfmaker85383]

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.

[Neil GreenawayParticipant @neilgreenaway71611]

This is a topic that’s really caught my interest!
Could you change the headstock oil….even flush with kerosene or red diesel to remove as much of the contamination as possible. Dry then new oil…..maybe a 68 grade hydraulic oil.

That middle od you clocked is on a sliding gear isn’t it so will be subject to tolerance accumulations….even a sliver of the bronze washed inside the splined I/d could give you the eccentricity, and the slight cyclical knock i think you mentioned and even generate friction and heat when running cyclically in contact with the mating gears.

If it were me I would make up a pin wrench….maybe some pipe and a roll pin and a bit of welding and tighten up that ring nut you had your hands on in the last 3 videos. Loosen the socket screw and adjust per the manual. The bearing might actually be ok…..can you do any further damage if it isn’t. Even if you were able to flush into the splines in the sliding back gear you might clean out some particles…..maybe a tin of aerosol brake cleaner as it has a bit of force with the spray.
Just some ideas….not necessarily ideal if you are seeking 100% perfection but easy low cost practical ideas that might get you going until you decide if new bearings are needed?
Neil

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

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

[Sebastian YorkParticipant @sebastianyork93348]

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

[John McNamaraParticipant @johnmcnamara74883]

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..

[Nicholas FarrParticipant @nicholasfarr14254]

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.

[Swarf MakerParticipant @swarfmaker85383]

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!

[HopperParticipant @hopper]

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

[SillyOldDufferModerator @sillyoldduffer]

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

[Sebastian YorkParticipant @sebastianyork93348]

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

[HopperParticipant @hopper]

Posted by Sebastian York on 20/12/2018 18:19:41:

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.

 

This is not surprising. A dial indicator is not designed to run on a rapidly revolving shaft. Anything above hand rotation speed is too fast for a dial indicator to keep up with. And it's terrible bad for the dial gauge.

If you have slack in the bearings once the machine has been warmed up, it's best measured by holding a long piece of bar in the chuck and yanking up and down on it with a dial indicator reading off the spindle right behind the chuck.

Your preload test sounds about  right. With a 200mm chuck, radius is circa 4 inches, multiplied by 2lbs, gives 8 inch pounds of torque. (Don't trust my math, I majored in English Lit. at college. Check it yourself.) IIRC target torque is 8 to 10 inch pounds?

But, is there a seal or seals on the spindle to stop swarf getting into the bearings? Often these seals would need to be removed to get a true torque reading because they drag on the spindle. Refer to your manual on that point.

 

 

 

 

 

Edited By Hopper on 21/12/2018 07:22:34

Edited By Hopper on 21/12/2018 07:34:02

[HughEParticipant @hughe]

Sebastian, you may have more luck getting suitable belt from a supplier like Henderson bearings in Ringwood. There must be a similar outfit near you in Exeter. They tend to have a wider knowledge than motor factors.

Hugh

[BazyleParticipant @bazyle]

Posted by Sebastian York on 18/12/2018 19:40:04:

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

Sorry, only just noticed this location, Unfortunately you have just missed the weekly get together of the Exeter DMES at St Katherine's Priory on Friday mornings. However I will drop a note around some of the retired members to see if they have some free time in this busy time of year.

**LINK**

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