New lathe arrived today : The ongoing saga

[Ketan SwaliParticipant @ketanswali79440]

Hopper,

I will try to reply to various point, but the response may be long. Sorry!

Hopper,

You are right, at present it is best for Brian to use the lathe as it is. If it isn't broke, dont fix it.

Regarding your questions on metal shields (zz) and rubber seals (RS or 2RS):

A Metal shield 'z' is located in the outer ring of the bearing only. Usually there is about a hairline gap between it and the inner ring of the bearing.

A Rubber seal 'RS' is located in the outer ring of the bearing, and depending on the bearing/seal design, it either just touches the inner ring like a lip, or slightly folds in, into the inner ring of the bearing.Nearer the inner ring, the seal is thinner in thickness in comparison to the rest of the seal thickness.

A 'z' shield as a result does not create any friction, but an 'RS' seal does…but very little. Advantage of 'z' shield is an increase in speed in comparison to the 'RS' seal. However, an 'RS' seal provides better protection against contamination from dirt/swarf/finer dust ingress.

Generally, all the bearings used in these kind of applications for lathes and mills are designed for accepting speeds which are higher than most manual machines are capable of. So, in such situations, the use of RS seal over Z shield does not have major significance.

Where there is consistent high load and heat, the z shield may be better suited.But again, in the machines used in this environment, I have not really come across this problem.

It is not the seal or shield which could put the stress on the motor. It is likely to be the torque set on the spindle which is more likely to have an effect on the motor.

Other comments:

– preload process has to take place with care, especially if a circuit board does not have overload protection. Too much preload could put a lot of stress on the motor, which in turn draws power through the circuit board, and if it is not able to cope and overload does not kick in, then it could blow the board and or damage the motor.

– as a general rule, Angular Contact bearings (ball) and taper roller bearings are not sealed. Rubber seals on Angular Contact Bearings (ball) have come about in recent years only. Looking at the exploded diagram 8.2 on Brians Baby Optimum, where the spindle enters the headstock casting, it suggests that there is bearing 6003 ZZ. Where such a spindle enters a C0 Baby lathe headstock, 6003-2RS bearing is used, offering better protection against dirt/dust/swarf ingress.Perhaps this may not be so critical in Brians Baby Optimum as the spindle flange may be bigger offering some amount of protection.

– Heat – reasons for: excessive grease, no grease, lack of running in, or too much pre-load..this is all provided the headstock is assembled correctly. If there are sealed or shielded bearings, they generally are greased with the correct amount of grease when the bearings were made. If open bearings which means without shields or seals such as normal angular contact bearings (ball) without 2RS and taper roller bearings, they should only be packed with between 20% to maximum 25% of the internal volume with grease. I have seen many people make the mistake of overpacking them with grease and then complaining about over heat generation.

Where an open bearing is used such as a taper roller bearing and it has been assembled dry as mentioned in another thread, well that is just poor assembly, and it will generate abnormal heat.

Lack of running in : once everything is installed and a running in procedure is followed, one will notice an increased amount of heat generation within the first 30 mins to one hour, depending on application, bearing type, speed, over time. There after, the temperature will start to come down and settle at a point. This settlement at a point temperature is different based on machine/housing etc.What is too high is difficult to say, and this is based on experience. Depending on the machine, application, speed, load, generally I worry above 45~60 Deg.C depending on the machine, spindle type, speed, and definitely stop if the temperature approached near 80 Deg.C, because at just after this point the chemical properties of the grease change in most manual lathe/mill applications, and in turn the surrounding bearing metal elements start having variable issues. I tend to measure the temperature outside the casting at the thinnest part of the headstock casting and the circumference of the bearings where they are seated in the housing – front and back. WARNING: there is no one answer for every machine.It is down to experience.

[Ketan SwaliParticipant @ketanswali79440]

Too much pre-load : This is normally done by setting of locking nut/s. Most of us do not have specialist equipment for this, so it is down to 'suck it and see' approach. Everyone has a different approach. This is what we do when changing the mini-lathe bearings to angular contact bearings (ball) or taper roller bearings, and I will use a mini-lathe as an example. Similar principal could be applied to Brians Baby Optimum, provided one can figure out which nut to tighten to put on a pre-load on an angular contact bearing (ball). I would hesitate to apply this idea to the ball bearings in place in baby lathes, and not because of country of origin of bearings!…just because ball bearings are not designed to accept too much pre-load, and in Brians baby lathe case, the said bearings are slim section.

So, in the case of a SIEG mini-lathe, there are two locking nuts on the spindle. The inner locking nut puts on the pre-load, the outer locks the inner one in place. First lock the inner nut on the spindle, and then tighten it between 5 to 10 degrees. Lock the outer nut onto the inner nut. hand rotate the chuck for feel. If it feels too tight, then loosen the inner nut, etc.. If it does not feel too tight, start the machine at low speed, and slowly increase the speed over a period of 15 minutes to start running in the bearings. WARNING: If too tight and if you do not have overload protection (C2 mini-lathe), be careful. If you have overload protection and if it is too tight, the machine will stop and the overload light will come on. So, you loosen the nut, and repeat. If all goes well without any issue, making sure that the machine is warm, i.e. it has warmed up before use, put in a piece of material which is to be turned, and turn it to see if there is improvement. If all is well, then nothing to worry about.Otherwise, repeat the earlier steps, tightening the nut by very small amounts.Generally, 15 minutes is not long enough for running in. You may find that after some 'x' hours of use, you will need to repeat this process, but always take care about how much preload you are putting on to avoid damage to the motor or circuit board or other parts, and generally warm up the machine before use.

About Grease: General purpose NLGI2 lithium based grease such as Castrol LM which you can get from your local garage is fine – nothing special necessary for most manual lathes, but if you decide to use slicky Moly, then please only use/put in between 15% ~ 20% of the internal volume of the bearing. Moly should only be used if you do not have a regular maintenance program.

Some people will disagree with various points I have made. I am not interested in getting into a debate on such issues. This is just my point of view based on our companies experience. I accept and appreciate that others have their own views.

Ketan at ARC.

[Ian S CParticipant @iansc]

Not on the topic of bearings, but a possible mod in future, a cooling fan(if not fitted) for the circuit board, just to get some air moving, the temperatures get into the 40s in Northern Queensland, and if the motor was going to be used at low revs, an extra fan on that too, these have been mentioned on other threads on this site.

That live centre may just have a needle roller, and some simple thrust bearing.

Ian S C

[Gordon WParticipant @gordonw]

Grease in bearings- I remember when moly grease first came on the market, about early 60's ? The makers advised that moly should not be used for running -in or roller element bearings. This was because the friction would be to low, running in would be to long. More importantly bearings might not revolve and flats could form. This is from my very sketchy memory ,and things may have changed since then

[Ketan SwaliParticipant @ketanswali79440]

Bearing makers dont like Moly, but makers of Moly have changed their advice. About 15 years ago, I had a debate between NACHI U.K. General Manager, Torrington U.K. Head of Technical, (both now retired), myself, and makers of Molyslip. Both bearing makers absolutely did not want to know about Moly, and Moly insisted that it is good. Bearing makers view was that Moly would not allow the bearing to run-in, especially if used in the same quantity at general LM type grease, i.e. 20 to 25% of internal volume. Compromise, use less, Moly, i.e. about 15% of internal volume, where results were found to be similar!. Keeps both sides happy. But it is said that if a particular grease is used from the beginning, one should avoid changing over to another type during replacement.

Personally, I would use LM only, or blend the two if you know what you are doing, with a higher % of LM with a lower % of moly in the blend. I too dont like Moly, but recognise that Moly has its place. Both camps of choice have strong views in support or against. If you want low maintanance, then lower volume of Moly to be used, or with LM blend is a good compromise. Your choice really.

Moly is used extensively for trailer wheel bearings, especially where such trailers are used in wet or near wet conditions, because it slicks like …

Ketan at ARC.

[Nigel McBurney 1Participant @nigelmcburney1]

The tub of Castrol moly grease states on its label "not for automotive bearings" I looked at the label fter I found my trailer bearing rollers looked rather dry and not being lubricated after using moly grease for some time.

[Gordon WParticipant @gordonw]

Thanks for that Ketan, shows my memory is not as bad as I thought. Off topic- I've found the best grease for trailer hubs and similar is a green coloured stuff, sold by ships chandlers etc. called xtra heavy duty wheel bearing grease, or similar.

[Ketan SwaliParticipant @ketanswali79440]

Posted by Nigel McBurney 1 on 18/09/2015 14:08:53:

The tub of Castrol moly grease states on its label "not for automotive bearings" I looked at the label fter I found my trailer bearing rollers looked rather dry and not being lubricated after using moly grease for some time.

I agree with you to a point. But it is like Marmite, and you may want to look at this **LINK**

Many people with trailers do use this on their trailer bearings. Right or wrong is a debate I had with them 15 years ago. Even today you will fail to get a clear answer for or against.

Ketan at ARC.

[JAParticipant @ja]

My initial reaction to this thread was that Brian needed a visit from a friendly soul to give him advise and help. That was before I realised he lived in a remote part of Oz.

There has been so many sensible questions asked and likewise good and interesting advise given that, I feel, when the thread falls dormant it should be edited, just to tidy it up and given an index, and published for the benefit of others generally.

JA

 

Edited By JA on 18/09/2015 16:31:13

[AjohnwParticipant @ajohnw51620]

I think one of the things about moly is that there is moly grease and there is moly grease. There is a type that is used on articulated lorry 5th wheel – that's the one the whole trailer hinges on with many tonnes on it. It's very thick high pressure stuff. People sometime think this is what moly grease is always like.

Arc sell some high speed moly grease – I think – my tin is yet to surface. They now have a gp one so mine might be too. I bought it some time ago. These are nothing like 5th wheel grease.

The motor industry don't like it at all or when it's used as an oil additive. They don't like people changing the engine oil too often either. Both can extend life far more than they are happy with. One problem that can occur when it's used in engines is that it can prevent initial running in. There are also claims that it can poison sensors. This was long before this aspect was as complicated as it is now. In fact there weren't any sensors in the exhaust or the engine oil in most cases. Ford on the other hand bring out the black stuff and start using it if they have problems with bearing type things not lasting through warranty.

I'm a firm believer. I once drove a car with a hole in a piston that blew all of the oil out of the exhaust for 20 miles keeping the revs up so that something showed on the oil pressure gauge – air. The AA emptied the oil out of a mini and drove it to London and back. All they found when they dismantled it was slight signs of over heating. Both had been treated with it for some time – not the same as just pouring it in. I've used it on every wheel bearing on all of the cars I have had when I did that sort of thing myself. Caravans too. Some people seem to think it has a molecular effect between the boundaries of rotating parts. I'd guess this is why the bearing people argue about it but they in real terms may be exactly the same as the automotive companies. I obtained my tin of a castrol MS3 equivalent rather early on from an uncle who was an aircraft fitter. Now I just have the car serviced. It might cause grief on modern sensors. In fact I'm pretty sure motor manufacturers would make sure it does if they could.

My boxford has been running on it since I had it. Initially I pocked out all of the grease I could and then put some moly in it. Now it's all moly. These are taper rollers. It has a 3 morse spindle. I gauge the running temperature inside the spindle right under the rear bearing to be around 40C once the lathe has warmed up. Sort of nice and cozy warm not hot. If it was around 60C I could probably keep my finger there but it would be rather uncomfortable. I've used the same test at work on electronics before getting a contact thermocouple out. It's not an exact science.

I've no idea how this will work out on other lathes. Some aspects of headstock design are probably a bit of a black art – eg what bearing heating effects do to any preload that might be there. There isn't any preload at the front on some designs and these do show improvements when they warm up. Boxford bearings tighten up a touch.

John

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[Gordon WParticipant @gordonw]

Back to moly- John , the trouble is it is too good for some uses. I've got nothing against it for some uses. Many years ago I had a Norton Dommie, lost the sump plug somewhere, but had moly in and all was ok. Also not recomended for manual g/box because the synchro clutch doesn't work.

[Neil WyattModerator @neilwyatt]

Not sure, but it may have been the key ingredient in Slick 50.

I'm hoping to get the astra running again on the weekend. Dollop of moly on each cam follower to make sure they don't score up waiting for the oil to get through.

Neil

[AjohnwParticipant @ajohnw51620]

I'm sure I put moly in a shogun gearbox without any problems other than a 3ft lever to undo the filler plug. It was a one shot gearbox treatment.

John

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[Michael GilliganParticipant @michaelgilligan61133]

Posted by Neil Wyatt on 18/09/2015 19:16:33:

Not sure, but it may have been the key ingredient in Slick 50.

.

An interesting MSDS

MichaelG.

[HopperParticipant @hopper]

Thanks for the further input. Interesting stuff indeed.

Ketan, yes I too am a great believer in "If it ain't broke, don't fix it" especially with a new machine not yet bedded in.

Thanks for the info on the bearings and particularly pre-load vs motor overload on these micro machines. Something I had not thought of, being used to larger machinery.

Surprising how many people will pack a bearing 100 per cent full of grease. One job I worked at, they had the main air conditioning blower for the hospital running on spherical roller bearings. Shaft diameter about 100mm, driven by 50hp or so motor. They had a grease nipple on the top of each bearing pillow block and once a week would hook up the grease gun and pump until a good handful of grease oozed out the seals at the shaft. "Making sure she gets fresh grease every week". Then they could not work out why the bearings failed every six months or so and would not believe over greasing could cause the problem.

On the methods for judging preloads, I always use "feel". BMW motorcycles that I mess with sometimes have tapered roller wheel bearings and a complex setting procedure involving the winding of string around the axle and measuring force to unwind it with a fisherman's spring scale etc. But I found over the years that "Zero drag, zero shake" works perfectly well, as felt at the wheel rim by hand.

And I like to run marine "waterproof" grease in wheel bearings. Does not wash out when the motorcycle is cleaned. The moly debate sounds like the synthetic oil debate – will go on forever with no clear answer. IT used to be motorcycle and car manufacturers said don't use synthetic oil for running in. Now many cars and bikes come from the factory with synthetic oil inside. There was also some myth about roller bearing rollers skidding with synthetic oil. But now even Harley Davidsons with roller bearing crankshafts use synthetic oil with no problem.

BTW, here is a handy little lubrication tip: for change gears etc use spray-on teflon motorcycle chain lube. Spray it on and let it go tacky overnight before starting up in use. No fling, no mess and full of EP lubricants perfect for gear teeth.

It's all a learning curve and that is what makes life interesting, eh.

[Neil WyattModerator @neilwyatt]

Posted by JA on 18/09/2015 16:28:15:

There has been so many sensible questions asked and likewise good and interesting advise given that, I feel, when the thread falls dormant it should be edited, just to tidy it up and given an index, and published for the benefit of others generally.

JA

Having been taken to task for correcting spelling errors in thread titles, I suspect I would be hounded out for revisionism if I did that. And where would I draw the line between useful post and blather, even if the extremes are clear?

> IT used to be motorcycle and car manufacturers said don't use synthetic oil for running in.

Truth be told, once the technique of micro-finishing was perfected cars don't actually need a proper 'running in' any more.

Neil

[JAParticipant @ja]

Posted by Neil Wyatt on 19/09/2015 09:42:08:

Posted by JA on 18/09/2015 16:28:15:

There has been so many sensible questions asked and likewise good and interesting advise given that, I feel, when the thread falls dormant it should be edited, just to tidy it up and given an index, and published for the benefit of others generally.

JA

Having been taken to task for correcting spelling errors in thread titles, I suspect I would be hounded out for revisionism if I did that. And where would I draw the line between useful post and blather, even if the extremes are clear?

Neil

Looking at the divergences from the thread on MoS grease and synthetic oils I see what I mean. It is very easy to get carried away from the main subject (I could add my pennyworth by mentioning synthetic oils and running in on an Aprilia Pegaso).

I think indexing is the most important, then acknowledging divergences from the thread and, possibly, spelling corrections.

This posting diverges from the thread and as such ………

JA

[Neil WyattModerator @neilwyatt]

To be honest, the way that search engines have developed, it's easier to let them do your indexing for you.

Neil

[AjohnwParticipant @ajohnw51620]

Oil technology took the motor industry by surprise Neil but it didn't take them long to take advantage of it and get wear rates back where they want them to be.

Noticing comments about lubrication other than bearings and seeing mention of greasy substances I would say don't. It's much better at catching bits of swarf than a thin coat of oil. I have just bought a used Wabeco mini and it has grease all over the lead screw. I'm not looking forwards to cleaning it all off and off the rack too. It also has a grease nipple for the front bearing to pump a bit in every 500 hrs – not that unusual. So much for only adding a bit as it will fill up, It also has grease on the tumbler reverse and as usual the end of the spindle is inside the end cover. I suppose that bits will miss these and as the rest uses belts it doesn't matter. When the lathe is started up initially there is a tinkling type sound that goes away in seconds. Not fully sorted but initially seems to be down to the tumbler gear arrangement settling down. I suspect the mesh may be out. I've seen mention of using photo copy paper to set the mesh. I mentioned this elsewhere as I thought some on might chime in. They did. The theoretical clearance on Boxford gears is around 0.0015" not photocopy paper thickness. Maybe the extra thickness allows passage for swarf.

The lead screw is so well out from the edge of the bed that it's bound to catch swarf. Doh – I suppose it has to be as if the bed was any wider the bed guide might not work correctly. I have looked around for spring covers – none found for straight forward mail order so far. Only phone for a quote. Arc did something once but I didn't like the way they worked.

John

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[AjohnwParticipant @ajohnw51620]

Posted by JA on 19/09/2015 12:13:30:

Posted by Neil Wyatt on 19/09/2015 09:42:08:

Posted by JA on 18/09/2015 16:28:15:

There has been so many sensible questions asked and likewise good and interesting advise given that, I feel, when the thread falls dormant it should be edited, just to tidy it up and given an index, and published for the benefit of others generally.

JA

Having been taken to task for correcting spelling errors in thread titles, I suspect I would be hounded out for revisionism if I did that. And where would I draw the line between useful post and blather, even if the extremes are clear?

Neil

Looking at the divergences from the thread on MoS grease and synthetic oils I see what I mean. It is very easy to get carried away from the main subject (I could add my pennyworth by mentioning synthetic oils and running in on an Aprilia Pegaso).

I think indexing is the most important, then acknowledging divergences from the thread and, possibly, spelling corrections.

This posting diverges from the thread and as such ………

JA

Some people book mark threads – even people who post to save them repeating themselves. Unusually on this forum people do seem to search it. Hard thing to balance because it could be that all questions are answered some where so there is no need for any one to post at all.

Lubrication is a fundamental aspect of lathes not just bearings. There is no harm in discussing how it applies to other areas – it's more information. Why not just read the first few words and skip it if it's of no interest.

John

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[Brian JohnParticipant @brianjohn93961]

I had some problems with the finish again today. So I stopped and checked all the usual suspects : the cross slide had quite a bit of play in it which I have now fixed. It has only had a few hours work since Hopper adjusted it so I am a bit surprised. Is this normal for a new lathe…or any lathe ?

I am going to give the live centres a miss for a while and I will stick with the dead centres. Is it worth paying a bit extra to get the carbide tips ?

[HopperParticipant @hopper]

Posted by Brian John on 20/09/2015 12:17:31:

I had some problems with the finish again today. So I stopped and checked all the usual suspects : the cross slide had quite a bit of play in it which I have now fixed. It has only had a few hours work since Hopper adjusted it so I am a bit surprised. Is this normal for a new lathe…or any lathe ?

I am going to give the live centres a miss for a while and I will stick with the dead centres. Is it worth paying a bit extra to get the carbide tips ?

Was that the movement of the cross slide or the whole carriage? Either way, It could be just the bedding down process if the original machining had some high spots etc. Either way, when you have used the machine a bit, if the problem continues we can take it off and put some bearing blue on it and have a look at what is going on. From what I have read, the gib strips can sometimes need a bit of a touch up on some emery paper on a piece of plate glass etc. I have all that gear, so no problems if needed.

I've no experience on the carbide tipped dead centres but the HSS ones work ok as long as you keep them lubricated and remember to check the tension on them particularly when machining ally which will expand with heat quite a bit and put pressure on the centre. It may be the carbide tips alleviate this problem – one less thing to be thinking about while machining.

[Brian JohnParticipant @brianjohn93961]

The movement was only in the cross slide so it was easily adjusted. I was surprised though as this was okay24 hours ago !

Some people have posted a link to clickspringprojects.com : I have been in touch with Chris from this website and he said that there are no lathe courses for beginners in Cairns. There are courses for apprentices but not for people like me. The government did away with this sort of thing many years ago as a cost cutting exercise.

[HopperParticipant @hopper]

Posted by Brian John on 21/09/2015 02:10:16:

The movement was only in the cross slide so it was easily adjusted. I was surprised though as this was okay24 hours ago !

Some people have posted a link to clickspringprojects.com : I have been in touch with Chris from this website and he said that there are no lathe courses for beginners in Cairns. There are courses for apprentices but not for people like me. The government did away with this sort of thing many years ago as a cost cutting exercise.

Brian, I did see a notice in the local Sun paper that the Irene Street men's shed has a meeting weekly on
Tuesday mornings.

Their contact details are

Email: cairnsmenshed@gmail.com
Phone: (07) 4053 5045

and they have a website if you google it.

They might have some kind of classes etc?

[Brian JohnParticipant @brianjohn93961]

I called them a few minutes ago. There is a meeting tomorrow morning but I will be at the chiropractor ! There is somebody there every day until 3.00 so I will be going this week ; it is only 5 minutes drive from here.

I have been reading the book ''Model Engineering'' by Peter Wright. It is the best book on lathes I have come across. On page 269 he talks about adjusting the gib screws for the top slide and cross slide:

'' This adjustment should preferably be carried out with the feedscrew removed so that a proper feel of the fit can be obtained and the locking nuts should be tightened and the fit finally assessed before the feedscrew is remounted ''

I have never heard of removing the feedscrew before making adjustments. Is this necessary ? I do not see how you could get a feel for anything if the feedscrew has been removed.

NOTE : I will NOT be doing this anytime soon.

NOTE : The ''Men's Shed'' website is blocked by my antivirus. It rarely does this with any site  so it is not just the title !

Edited By Brian John on 21/09/2015 02:55:29

Edited By Brian John on 21/09/2015 02:56:10

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