New lathe arrived today : The ongoing saga

[John Stevenson 1Participant @johnstevenson1]

As an aside to all this I bought one of the first early C0 lathes. Don't know if I was lucky or unlucky as the case may be but mine worked OK as it was straight out of the box.

It was bought to do small jobs, where I can get it out a cupboard it lives in and then use it and put it away. I am not short of lathes and this one fits a niche market in the ownership of machines.

Not long after I had mine there was a bit of a witch hunt going on with these lathes. You know the usual not fit for purpose by the usual not fit for purse crowd who really want a Myford S7 with attachments for the same price as the C0.

At that time and before the after market backplates were available I wanted a spare backplate for this lathe and was going to belt one out on the largish TOS lathe I use daily but as an exercise I decided to see if i could make this backplate on this C0.

I think it was 60mm is diameter, not sure but could easily check. It was a size the existing 3 jaw chuck could just manage. So the blank was sawn off a long bar and then fitted into this lathe and the top hat and all the operations were carried out on this lathe using two home ground HSS tools, one knife tool and one boring tool. The only operation not done on the lathe was the internal spindle thread which I would have preferred to screw cut but as this lathe doesn't screw cut, it was tapped.

The backplate was revered and mounted onto the spindle and the rest of the operations, facing and register carried out. This was in normal mild steel, something like EN3B and not alloy or one of the leaded steels as I wanted to see if this machine was capable of it and yes, the answer is, it was, albeit very slowly compared to how fast I could have done it on the TOS.

[John Stevenson 1Participant @johnstevenson1]

John W1

 

I do take strong exceptions about what you posted earlier on a public forum in respect of sending for a non specific part and then sending it back if it didn't fit.

 

I saw this a while ago on another forum where a guy wanted a 4" brick hole cutter for a waste pipe. He posted he went to B&Q, bought one, drilled his hole and then took it back as not fit for purpose !!!!!!!!!!!!!!!!!!!!!!!!! for a refund.

 

Now that might get a laugh from some areas but I think is despicable and pathetic. I was in two minds to go into your post and delete the reference but decided to reply instead.

 

My wife when she was alive used to run an Ebay shop and also a web based shop and had a very good reputation but she still had to deal with these sort of people, saying they had not received a package when every other package in the same shipment found it's way, always the same people but after she started send it tracked, guess what, never happened again.

 

All that happens long term is these people get clocked and suppliers refuse to deal with them. I no longer sell on Ebay and the web site is closed for the time being but when it does start up again I still have her list of the unwashed.

And a new list to add to it……

Edited By John Stevenson on 14/09/2015 19:36:50

[AjohnwParticipant @ajohnw51620]

I don't advocate buying mail order on a whim and sending back. The only reason I mentioned it is that if he wants them Brian is in a bit of a fix but must admit I don't see the need for a rushing and in real terms the Oz supplier should be able to supply them.

Personally Ketan I feel that the baby lathe suffers from a type of size problem. I'm a design engineer that has always worked in manufacture so am well aware of it. There is an assumption that because something is smaller it must be correspondingly cheaper but unfortunately when it comes to things that need machining it really isn't as simple as that. Or anything else really. For the same features the only thing that really changes is the cost of the raw materials which will be relative low and a 2ndry knock on effect of reduced machining times which wont be that significant over a range of sizes. The plant will still cost the same and etc. So the next step to reduce cost and it does do that is to omit features and or parts that would normally be there. That's why I said not that one to the friend, the general make up the machine. He by the way is fairly competent. I had warned him about the tidying that would probably be needed. I've done that myself on a small miller – bought used off some one that couldn't make any use of it. I did, it mostly needed adjusting. The novice that bought it off me was also happy with it. Casting kit is a term I have seen used round here so just repeated it.

I might add that I bought 2 baby lathe compound slides of you Ketan and didn't send them back. No use to me as worse than expected. I could sort them out but wanted something quickly and the clearance used on the lead screw "bush or lack of it" suggest I might find that they can't be sorted out. I feel this sort of thing is another aspect of Chinese lathes at times. In this case the parts have been machined and in real terms shouldn't even need to be as they are even less a bush.

The baby lathe isn't unique I also knock Myfords with good reason but again compared with what could be called real machines they were cheap as shocking as that sounds. I often mention ML10's and Speed 10's to people looking for a small lathe. Another example of a machine on a budget at the manufacturing end. Personally I feel s7's could have been better for little additional cost other than maybe plant but going on the later offering they bought that anyway.

In general people will tend to get what they pay for. The trouble is as I see it is expectations and that can be difficult when some one asks what machine and in my experience people are likely to take no notice as they feel that if there were any problems it wouldn't be sold. The one I mentioned isn't my only instance. Maybe they live on planet zod but in some big boys toys area some retailers take advantage of peoples naivety. Actually I feel lathes and machine tools are no where near as bad as some other areas.

If some one relates the above to much heavier lathes please go lie on a motorway and play with the traffic. Thw weight aspetc at some point will come into it. Perhaps I have managed to explain why things like a baby lathe will have limitations.

John

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[Chris DentonParticipant @chrisdenton53037]

Posted by Brian John on 14/09/2015 18:40:05:

The Chinese can make decent anything and when I look around my ''workshop'' it is hard to see a tool that was NOT made in China.

The Chinese make a wide range of qualities of products, it's just that in the UK we decide to import the crap.

[Chris DentonParticipant @chrisdenton53037]

Posted by John Stevenson on 14/09/2015 19:27:17:

I do take strong exceptions about what you posted earlier on a public forum in respect of sending for a non specific part and then sending it back if it didn't fit.

Like it or not, UK law allows it. If you don't like it then speak to the government.

You can drive at 70mph on the motorway, doesn't mean you have to if you don't approve.

I think I've sent one item back in the last year that wasn't suitable for what I wanted it for.

[John Stevenson 1Participant @johnstevenson1]

Posted by Chris Denton on 14/09/2015 23:55:49:

Posted by John Stevenson on 14/09/2015 19:27:17:

I do take strong exceptions about what you posted earlier on a public forum in respect of sending for a non specific part and then sending it back if it didn't fit.

Like it or not, UK law allows it. If you don't like it then speak to the government.

You can drive at 70mph on the motorway, doesn't mean you have to if you don't approve.

I think I've sent one item back in the last year that wasn't suitable for what I wanted it for.

Chris,

Fine sending something back that isn't right but buying something sold for something else then bitching when it doesn't fit is different.

I have bought loads of stuff on spec that didn't work out for what i wanted it for. It wasn't the sellers problem so why should he have to have the hassle ? Note the example with the 4" hole cutter i mentioned.

Perhaps I'm too old fashioned and think trust is a desirable virtue ?

I deal with a lot of people in this hobby, socially and commercially and the vast majority are upright and trust worth citizens but you always get one clever bastard………………

[AjohnwParticipant @ajohnw51620]

Posted by Chris Denton on 14/09/2015 23:30:30:

Posted by Brian John on 14/09/2015 18:40:05:

The Chinese can make decent anything and when I look around my ''workshop'' it is hard to see a tool that was NOT made in China.

The Chinese make a wide range of qualities of products, it's just that in the UK we decide to import the crap.

There is a need to be fair Chris – cost.; It's possible to buy a very small Schaublin even now. Where I feel things are wrong is too much penny pinching though the pennies are probably some 10's of pounds as far as a buyer is concerned. If Schaublin quality is needed costs would escalate who ever or where ever it was made. Part of the price increase would be down to how many would be sold – not many at their prices. Many things are made to suite a particular market price wise. Actually in some areas that sets the price not the actual cost of producing what ever it is.

By the time Brian put a motor on a small Schaublin 70 and had it on a suitable stand he wouldn't be at all happy with the weight. Probably not with the weight of the lathe alone either.

I can see plenty of things in my workshop that aren't from china, some things I made myself, some others made, some used some new. I've recently added a mini lathe as well. Used as there is no way I would pay the new price for one of these particular ones. I've found a stupid design feature already. The way it's mounted and if I followed the suggestions in the manual it would probably distort the bed. A real silly. No feet projecting from the bed. Instead the casting has been drilled and tapped making it a bit difficult to mount it evenly without any distortion. The curious thing is that normal feet with a simple plain hole would be cheaper to produce and easier to mount. I sometimes think that the people who design them and also buy them don't look at lathes in general and then wonder why things have been done that way. Simple solution in this case – just make to 2 plates and fasten them to the bed and use holes in these to mount it. The person I bought it off made some screw jacks but they aren't suitable for the way I need to mount it. Most people would probably do just what the manual suggests. It came with a test report. One entry is interesting – if the head stock bearings are loose apply pressure to remove the play and then take the measurement. Actually as there is a little noise when the lathe starts from cold that rapidly goes away they are probably about right but as usual no sensible way of adjusting them is mentioned. It could be some other bearing anyway. There are several possible candidates.

John

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[Brian JohnParticipant @brianjohn93961]

Here are some photos. They are the best I can do with my camera. I took 20 photos and chose the best three. In photo 3 of the mandrels you can see the finish I was getting a few days ago. The one with the washers is a good finish and what I am getting now is beside it. Photo 2 is Hopper's tool ; we know that one is sharp.

Auto feed is MUCH worse than manual feed. All these photos are of manual feed.

Did somebody mention raising the tip of the tool height slightly above centre ? How does that work as I thought the tip should be in line with the dead centre of the tailstock ? I may try raising the tool by one shim later tonight.

Edited By Brian John on 15/09/2015 08:36:54

Edited By Brian John on 15/09/2015 08:39:26

Edited By Brian John on 15/09/2015 08:41:21

Edited By Brian John on 15/09/2015 08:42:26

[Nigel McBurney 1Participant @nigelmcburney1]

Looking at photos ,the tools are not suitable for finish turning,and I would not expect a better finish, the top tool with the groove is only a chip breaking tool for roughing and the second tool is too pointed,they both have side rake but no back rake,get someone to show you how to grind tools.

[HopperParticipant @hopper]

Hi Brian,

What did the tech have to say when he visited on Monday?

Which feed rate are you using? Have you made any changes to the feed gears at the left hand end of the headstock?

A couple of suggestions you might try:

• Drill a centre hole in that test piece and put the tailstock centre in place. Try taking same size cut with the same tool at the same feed and see how it compares. Let us know how the finish compares. If a centre improves the finish, the problem may (MAY) be spindle/chuck-related rather than carriage-related.
• Turn that toolbit we made around and try the other end. ISTR we put a bit of a radius on the other end which might help. The end you show in use was for getting in by the centre for facing etc.
• Try some different materials in case you have a piece of soft ally there, which will not turn well. Try the same ally you were using for the first mandrels you made and were happy with the finish. Also, try a bit of mild steel.
• Try varying the rpm. For ally about 12mm diameter ally you would usually run about 1,000 to 1500rpm. For 12mm steel, try about 800rpm. If no good, try going incrementally faster or slower.
• You mentioned you could see the tool moving in and out. Check if the movement is the carriage on the bed, or the cross slide on the carriage, or the top slide on the cross slide. You can check by putting your finger where the one part joins the other and feel for movement while taking a cut. Let us know what you feel.

[Roderick JenkinsParticipant @roderickjenkins93242]

The middle picture looks very much as if you are suffering from build up on the tip of the tool. This build up periodically breaks off which is why you get the cyclic variation. Hand feeding will provide a bit of variation with the feed rate which will help to break off the build up. Power feed is smoother so build up is probably worse. A dab of lubricant on the job should help considerably. Anything fairly oily will do but kerosene (paraffin) is the usually recommended lubricant for aluminium.

Well, that's my take from 12,000 miles away

Good luck

Rod

Edited By Roderick Jenkins on 15/09/2015 09:34:33

[JasonBModerator @jasonb]

One other thought on your poor finish Brian. It seemed to happen at about the same time you got some materials from the scrappy. Are you getting this poor finish on material from him or are you still machining the same stock you used on the early mandrels?

[HopperParticipant @hopper]

Posted by Roderick Jenkins on 15/09/2015 09:31:52:

The middle picture looks very much as if you are suffering from build up on the tip of the tool. This build up periodically breaks off which is why you get the cyclic variation. Hand feeding will provide a bit of variation with the feed rate which will help to break off the build up. Power feed is smoother so build up is probably worse. A dab of lubricant on the job should help considerably. Anything fairly oily will do but kerosene (paraffin) is the usually recommended lubricant for aluminium.

Well, that's my take from 12,000 miles away

Good luck

Rod

Edited By Roderick Jenkins on 15/09/2015 09:34:33

WD40 works well as cutting lube on ally too. And smells better than kero. (Brian has his lathe set up in the living room so domestic authorities must be considered!)

[JasonBModerator @jasonb]

Would be worth just lifting it outside to try it with a bit of cutting fluid.

Brian, were those done with the carrage locked or by moving the carrage?

[Steve PaveyParticipant @stevepavey65865]

"Did somebody mention raising the tip of the tool height slightly above centre ? How does that work as I thought the tip should be in line with the dead centre of the tailstock ? I may try raising the tool by one shim later tonight."

I doubt that anyone suggested that. Your tool tip should be at centre height. If you can't ensure that it is precisely at centre height then a thou or two below is acceptable. To set the tool, do a facing cut, starting with the tool below centre height, and gradually raising it until the pip just disappears.

Have you tried Jason's suggestion of locking the carriage and using the top slide for a longitudinal cut?

[AjohnwParticipant @ajohnw51620]

I did mention above centre turning in another thread. It's something people who can turn normally might like to play with.

If aluminium is sticking to the tool try reducing the speed you are using by 10 – 20% . Use Hopper's tool and as he mentions a rad will help improve the finish but it will also do something else that may help. If there is any aluminium sticking to the tool it can be flicked off with say a small screw driver or what ever.

Hoppers suggestion of using a centre will help correct another problem. If you don't have a revolving centre there will be need for some lubrication on it – lard out of the kitchen will help, grease would be better but if the centre is too tight it will still get hot and the ally will expand making it even tighter. It can expend when it's being turned as well.

Next question is that after you have taken a cut does the tool cut again when the tool is just wound back to the start without the centre in? Much – tiny shaving etc? Also if you measure your work is it showing much taper along it's length ? Do things improve a bit if you keep taking the same cut?

John

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Edited By Neil Wyatt on 15/09/2015 14:47:19

[Brian JohnParticipant @brianjohn93961]

I will try to answer all the questions but forgive me if I miss any. I was helping my wife with her new bicycle.

I knew somebody mentioned raising it ABOVE centre height but I was not sure where I read it. I have tried this and it DID improve the finish quite a bit. Why should this work ?

The technician never came a second time. I was hoping he would call back today but that did not happen.

I am using about 800 RPM. Increasing or reducing the speed does not seem to help the finish.

This is the same Aluminium that I have been using the whole time. It is from Norweld …not the scrap yard.

If I do not wind the tool out at the completion of a cut but wind it back along the piece (lazy !) then yes…..it does take quite a bit off on the return. Something I was surprised at. It has always been like this.

Using the centre is probably a bit worse than without a centre ; it certainly does not improve things. I do have a live centre but it is much bigger than the dead centre, making it harder to get in close on the tailstock end. I tend to only use the dead centre now.

No changes have been made to the gears. I am not going in there for a while !

NIgel says the top tool is not suitable but this is the RH cutting tool from the Arceuro set. Does anybody agree or disagree with this assessment ? Which is the finishing tool in the set ?

Hopper : I have tried both ends of the tool.

The movement I was getting was definitely in the carriage and there was a LOT of it….you couldn't miss it. You could see the tool moving up and down as you took a cut. All movement is gone now after I tightened up the adjustment screws underneath. It took me many goes but there is now no movement at all when I try to rock the carriage by hand. This is why I am surprised that I am still having problems as I was sure this was the cause.

NOTE : I prefer kerosene to WD40 but I will try both.

 

 

 

Edited By Brian John on 15/09/2015 14:03:53

Edited By Brian John on 15/09/2015 14:05:19

[Martin KyteParticipant @martinkyte99762]

If the tool is a tad above centre it may be rubbing slightly and polishing the surface or more correctly burnishing the surface. Did you mention how the swarf is coming off. With a good turning tool for aluminium having a good degree of rake the swarf should come off in ribbons with a nice swooshing noise a bit like cutting silk.

Martin

[Brian JohnParticipant @brianjohn93961]

The swarf does come off in long ribbons (nuisance stuff) but I cannot hear any swooshing noise because of the noise of the motor/gears/belts.

I forgot to mention before that I did try locking the carriage down and using the top slide to take a cut but there was no improvement at all. I was surprised at this.

Edited By Brian John on 15/09/2015 14:13:38

Edited By Brian John on 15/09/2015 14:14:05

[AjohnwParticipant @ajohnw51620]

What diameter aluminium bar do you have ? I'm pretty sure I know what is causing the problem.

John

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[Brian JohnParticipant @brianjohn93961]

It is 16mm diameter.

[AjohnwParticipant @ajohnw51620]

Use hopper's tool with the radius and set it on centre with the tailstock – usual thing – a very slight touch low to actually on centre. Be sure it's not above centre.

Have about 50mm sticking out of the chuck but make sure you are gripping it correctly. Face the end. If I'm right you will probably get a pip left in the middle that you may be able to keep going at to remove it or the tool might just always seem to jump under it. Often they just break off.

Then take a cut along it to clean the outside diameter up. I think if you stop at the end of the cut and measure the diameter up by the chuck it will be less than the end because the bar is lifting. It can do something similar if the bar is bending but I'd be surprised given the size of cut you can take if that will have much effect on 16mm bar.

As you may have problems with the first cut try the same thing again. The let us know what the difference in sizes are.

I suspect the bearings are loose but it really would be best to REALLY ensure that this is causing the problem before doing anything about it. It explains the rings your getting because the cut lifts the bar but each time the feed rate drops off the bar drops and creates a ring. This can be improved by increasing the feed rate especially if power feed is being used – the cutting pressures stop high and constant enough all of the time to hold the work steady. The cut has to lift the chuck, spindle and work. I'm hoping 0.3mm is enough but the rad on the tools will help. If the feed is too slow all sorts can happen. If the work lifts as it's being cut the tool will cut again when it's run back to the start. That can also be down to the work bending – centres help with that. This is why hand feeding isn't easy because there is always some degree of flex some where or the other and even micron deep grooves will show. The better the finish produced the more apparent they will be.

As this has happened rather suddenly it shouldn't be bearing wear which will cause the same problem eventually. What can happen when lathes are assembled is that the bearings aren't pushed fully home so they move when the lathe is used. My Boxford had this problem even though it had seen years and years of use before I bought it The bearings loosened each time I drilled a 1in hole. Looking at the results you have had it wouldn't surprise me that if you held 300mm of bar tightly in the chuck you would be able to waggle it about and feel the play. People are usually concerned about amounts that need a dti to detect – some also bend the bar trying. It's always best to check this sort of thing by turning unless the problem is rather gross.

John

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[JasonBModerator @jasonb]

John, if the bar is lifting why does brian get a worse finish when he uses tailstock support than without? He also gets a worse finish when power feeding which should apply a constant load?

[AjohnwParticipant @ajohnw51620]

In my view most lathes have cut depth and feed rate combination for some material that will give the best even finish. This might result in an obviously turned finish because the feed rate has to be so high. If the power feed is too slow for the cut to take out the play it can tend to oscillate and bounce about. I get that to a certain extent on my Boxford at times – fix increase the feed rate and it goes away. It's most likely to happen at 1 1/2 thou per rev and usually disappears even with just a small increase. I do mean small as well, the steps at the fine end are insanely tiny.

I'm a bit bemused by the centre too but as it's a none rotating one I'd guess if Brian used enough to push the whole lot home it would overheat. The centre wont stop the other end from moving about at the sort of pressures he could use.

The bearings might explain his depth of cut problem to some extent as well. Best explained with a Pulta I bought with a 3 jaw chuck that is bell mouthed. If a cut is taken too far away from the chuck the bar moves and grabs and makes the belts slip. A bit different to loose bearings but the same sort of thing might happen. Brian not getting the work gripped fully by the chuck can have the same effects. I did explain how he should put things in the chuck earlier so hope he is doing that. The actual run out of his chuck is likely to be pretty low but not if the bar is cock eyed in it and if it's like that the work is very likely to move. That might be another reason for the problem but why sudden?

John

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[Steve PaveyParticipant @stevepavey65865]

We may never know without a video…

I'm still not sure from the previous posts which direction, x y or z, the play in the saddle occurs. We also don't know about possible play in the cross and top slides, or the tailstock spindle for that matter. At least one tool shown is not one that I would use for turning aluminium, and I'm not sure whether the op has a grinder and is able to ensure his tools are sharp.

As it is, every possible suggestion as to the cause has been made, but no-one knows the results of the fundamental tests that should have been carried out are. If it was me I'd turn a test bar from the largest diameter stock I had, with the end unsupported, followed by another with the dead centre, both using a freshly ground hss tool set at or just below centre height and using the auto-feed. Only if that produced really horrible results in terms of measurements would I go on to investigate play in the spindle, play in the tailstock, or play in any of the saddle components. Test one thing at a time, change one thing at a time and it might be possible to make sense of the results.

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