Tail alignment and gear handle play

[Neil WyattModerator @neilwyatt]

Just for completeness, these are the various arrangements for each of Dr Schlesinger's lathe tests. Click for a larger view.

Neil

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Hopper on 30/06/2015 13:32:23:

Posted by Eugene Molloy on 30/06/2015 09:19:26:

Link to the free E-book description **LINK**

That is a great book. Thanks for the link. Downloaded no problems

.

Hopper, That's rather curious !!

If I go to Eugene's linked page, it inludes the statement 'No eBook available'

… maybe I'm seeing a special version of the page, especially for iOS users.

MichaelG.

[john carruthersParticipant @johncarruthers46255]

this took me to a viewing page which I then downloaded;

https://ia801408.us.archive.org/27/items/whitworthmeasur00whitgoog/whitworthmeasur00whitgoog.pdf

[Michael GilliganParticipant @michaelgilligan61133]

John,

Yes, that's the alternative source that was provided in my previous thread [linked earlier]: What I found curious was that Hopper had managed to download via Eugene's link.

MichaelG.

[HopperParticipant @hopper]

Posted by Michael Gilligan on 01/07/2015 08:24:35:

John,

Yes, that's the alternative source that was provided in my previous thread [linked earlier]: What I found curious was that Hopper had managed to download via Eugene's link.

MichaelG.

My apologies. It was your link that I downloaded from. Got so absorbed in both Mr Whitworth's history and the Shelley issue on the linked thread I clean forgot where I was.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Hopper on 01/07/2015 08:52:41:

My apologies. It was your link that I downloaded from. Got so absorbed in both Mr Whitworth's history and the Shelley issue on the linked thread I clean forgot where I was.

.

That's fine then; thanks for confirming.

No need for apologies; I was just worried that I may have stumbled upon some odd Google-v-Apple behavior.

MichaelG.

[AjohnwParticipant @ajohnw51620]

Posted by Neil Wyatt on 30/06/2015 18:01:18:

Just for completeness, these are the various arrangements for each of Dr Schlesinger's lathe tests. Click for a larger view.

Neil

Good to see that a between centre test bar is used. Easy to make pretty accurately even on a lathe that is a bit out. Turning can be substituted for the other test bar but would be best to sort out head stock bearings first. In fact it's safer to at least check that before doing anything else.

Not come across the wire and weight before. Interesting one.

Really the other one is to turn in several ways first as that can help interpret results.

John

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[PeteParticipant @pete41194]

Finally!!!!!!!!

Hopper has injected some proper technique and much needed logic into this thread. There's been a lot of other good information posted also. My apology's but I do think my post might get a bit long winded.

I fully understand the OP's desire to adjust his lathe to get the best accuracy possible. I did the same with my little Emco compact 5 lathe, but I did so only after reading that Conolly book more than a few times until I understood as much of the techniques as possible. And most of what's on these hobby forum's is incorrect compared to what Conolly or Schlesinger have to say. I also got fooled for more than a few hours of wasted testing with a light weight dial test indicator bending a quite heavy mounting rod under the effects of gravity. That's all too easy to miss to be honest, and there's really no simple way to know for sure that gravity is or isn't affecting your results when swinging a DTI from the head stock. What I do now is turn a piece of scrap down to within .001"-.002" or the same in metric of either the tail stocks barrel's outside diameter, or the outside diameter of a morse taper blank arbour that fit's the tail stocks female morse taper. You then measure both of your plugs diameter and the tail stocks barrel or arbours parallel section.as accurately as you can with your very best micrometer. Then you use both the lathes carriage and the cross slide to run the finger of a .0001"s reading DTI across both diameters at both the head stock and tail stock. Simple addition or subtraction to account for any minor difference's in sizes for each diameter will then give you the exact numbers of your tail stocks position. I don't know of a simpler or better method that is any faster, more accurate, or easier to do that you can then be 100% positive your test numbers aren't being swayed by those gravity effects.

But the tail stocks centerline height is just only one single check. Just as important you also need to use that DTI to check that your tail stocks barrel isn't pointing to the left or right, uphill or downhill, and if that barrel move's it's position between locked and unlocked, or extended and retracted. Some will say it's only a mini lathe so what's the point of all that? Well it's impossible to try to compensate or correct for any errors if you don't know if they do or don't exist, or even how much those errors might be. And unless your test numbers are 100% repeatable, then your methods will be highly suspect to the point of being useless.

Machine tool alignment, and especially lathe alignment and and that mostly misunderstood "lathe leveling" is probably very close to the number 1 topic on almost any hobby machining forum out there today. And FAR TOO MANY will try and answer to the best of there ability what they think is correct. Yet the majority are basing those answers without taking the time to at least read what both Schlesinger and Conolly have to say, and who ARE those recognised authority's on the subject. Schlesinger's alignment and test procedures are available for free on the net. Possibly the Conolly book might be also. But almost all of us should be able to get a copy to read of the Machine Tool Reconditioning book through something called the "Inter Library Loan" system. I do own my copy, but it is almost $100 to buy it even today through Industrial Press. The book is boring to the extreme in large parts of it, but it will properly educate you so your answers in threads of this type are logical and well thought out reasoning. (Or at least I hope mine are) But in my opinion buying that book was the very best $100 I've ever spent on my shop and education about this so I finally did understand what the actual requirements really are. The subject is vastly more complicated than most understand I think. But those who haven't read it and then understand what's required are pretty obvious when they recommend (with the best of intention's) methods that are incorrect in these threads.

Lapping slides etc. is or would be just one example, yes it will make things much smoother, but there's zero control over exactly where and how much material your removing. Very light lapping can probably work after your initial corrections have been done Trying to maintain or even correct the alignments on a lathe in all 3 dimension's at the same time can't possibly be done by what so many say you should be doing with just that slide lapping. In fact it's all too likely your actually making the accuracy far worse unless your extremely lucky.Scraping and using some very expensive and reliable test equipment, along with a whole lot of logic, knowledge and experience would be the correct and best method. You can of course make a machine a bit better fairly cheaply, and the more skill you have will make your results better. None of this is just my opinion either,those are just the simple facts if your willing to put some effort into researching exactly what is involved.

We really should in my opinion be using these forums as a way to help educate ourselves. But they shouldn't be the only place your basing that all too important self education on. Yet today I see the problems of incorrect information on these forums as a large and growing problem. It should be exactly the opposite. Anyone ever wonder just how M.E.'s or the American term of HSM educated themselves before the internet was invented?

My sincere apology's for the length of this post.

Pete

[AjohnwParticipant @ajohnw51620]

The important aspect of a tailstock is the behaviour of a centre in it. Any test based on it's od assumes it's concentric which it may or may not be. Hence the need for a between centre test bar with varying projections of the tailstock quill.

I may have mentioned lapping with a mix of CIF kitchen cream and oil. This will not correct errors only improve smoothness and for perfection needs a bit of thought to make sure that the added smoothness is applied evenly along what ever slide it is.

John

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[PeteParticipant @pete41194]

Yes John I'd certainly agree that testing against the tail stocks OD would only be the first step. But if your metrology equipment is accurate enough? Then no lathe no matter how good or expensive they are including the worlds best that are available today including the temperature controlled spindle and bed machines that are designed for optical and/or laser equipment would be without fault. And yes you are 100% correct, the tail stocks OD is just a place to start. But I did have to shorten my post by over 2700 letters since the allowable limits on this forum don't like lengthly explanations of what are fairly complicated ideas that both Conolly and Schlesinger had. You do need to run multiple tests if possible on multiple areas just to start forming some ideas of where the problems might be.Then it will take some real thought and I think education before you can properly pinpoint where the those problems might be. To state the completely obvious, the cheaper your machine is, then the more knowledgeable you have to be to be able to wring the very best out of it. It's not impossible, but it does take a real desire to properly educate yourself. I've been learning about this for well over 30 years, and I never expect to ever know what I'd like to.

But…………..to end up so that you are 100% positive of the exact issues and exactly where there located with any certainty can take a huge amount of time,testing, thought and energy. That's where your own personal understanding and education starts. I highly recommend NOT asking questions on forums like this first, but you should be doing your own research through Google, and then possibly start to ask some questions on these forums only after doing so.

Pete

[Michael GilliganParticipant @michaelgilligan61133]

… .to end up so that you are 100% positive of the exact issues and exactly where there located with any certainty can take a huge amount of time,testing, thought and energy. That's where your own personal understanding and education starts.

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Pete,

Despite your obvious enthusiasm for the subject; I regret that you have lost some credibility/authority by your use of phrases like "100% positive".

May I suggest that you continue your research by reading some of the excellent publications on the NPL website ? … especially on the subject of Uncertainty of Measurement

MichaelG.

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P.S. … You may need to register/log-in to get access to some of the material, but it's well worth doing so.

Edited By Michael Gilligan on 03/07/2015 06:57:35

Edited By Michael Gilligan on 03/07/2015 07:04:59

[PeteParticipant @pete41194]

Michael,

Yes I do know about that uncertainty of measurement. So you are quite correct that there is no such thing as "100% positive" exact, or even perfection with anything while measuring. I did use an incorrect term I guess. But that NPL website does look interesting. Many thanks for that link.

Pete

[HopperParticipant @hopper]

I wonder how the OP is getting on with knocking that couple of thou off the tailstock of his budget hobby lathe?

[Nitai LeviParticipant @nitailevi73768]

It's the same as it was last time I posted… about 0.11mm high vs. 0.14mm high before I started.

Re some of what was posted more recently, I looked on Google and other places before asking on forums, but see no problem doing both.

If I didn't mention it, of course I checked how much the tail changes when retracted and extracted i.e. misaligned to the side, top or bottom. It was accurate to a point that I don't need to do anything about it.

The design of the tail on this lathe is such that making it misaligned to the side is practically impossible when lapping to adjust height. At least unless there's a bur or something causing side alignment at the very bottom part that is being sanded, which is something you could check (there's no issue with that on my lathe). Messing the up and down direction is definitely possible and the main reason I was worried about scraping and lapping.

By the way, I'd definitely buy a three or four times more expensive lathe if it meant having to mess with it a lot less – and it would mean that – but unfortunately the only ones I found had other "compromises" that I wasn't willing to accept for that price (I use quotes because one of those is being too big, which isn't a bad thing, I just didn't have the space for it).

FWIW here is a photo from before I started doing anything. Sorry there's no scale to give a better idea.

Edited By Nitai Levi on 03/07/2015 15:24:31

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Nitai Levi on 03/07/2015 15:20:59:

FWIW here is a photo from before I started doing anything. Sorry there's no scale to give a better idea.

.

That's a very informative photo, Nitai … Thanks for posting it.

Keep up the good work, and post us another one when you are finished.

MichaelG.

[Nitai LeviParticipant @nitailevi73768]

I just saw that the forum reduced the size of the photo. The original size is here **LINK**

[AjohnwParticipant @ajohnw51620]

You would be talking a lot more than 4 times the price.

This is a test pass off of a cheaper lathe Boxford made some time ago now. Just borrowed of the web.

They still make a lathe, maybe the super accurate tool room version as well. Price for these sort of numbers now – I believe it's over £3000 for a reasonable used example. New price not sure but could be 3 times that,

The tests shown on this sheet don't show where errors are – only the accumulation effect of them. They also tell users to correct errors down from this via bed strain using tests which involve actually turning.

On the other hand maybe they don't make light duty lathes that well as they might on purpose. On the other hand errors should reduce with size -. it's also possible to buy a new Schaublin of course.

John

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Edited By John W1 on 03/07/2015 17:51:31

[SaxalbyParticipant @saxalby]

Last I enquired of prices from Boxford the 330 lathes started at about £15000.

[AjohnwParticipant @ajohnw51620]

Posted by Saxalby on 03/07/2015 18:03:58:

Last I enquired of prices from Boxford the 330 lathes started at about £15000.

I forgot to add vat to the used price which when they can be found usually has to be added. I would have thought 15K was a bit high though or is it the TS version? The TS was designed and made to meet the most stringent specifications available. The Industry version more normal standards. I think they only do what is intended to be a training / school lathe now. Not sure.

I wonder at times but when I look at the bits and pieces I have with my ME10 the on cost over the basic lathe would really hurt even on a used one if it came with no bits. An old rule of thumb was that equipping a lathe may work out more than the cost of the lathe itself.

John

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[SaxalbyParticipant @saxalby]

John,

Yes,the £15k was for the TS version.

When I bought my ME10 it cost I think £1300 or so, but the add on even more. Got all the receipts somewhere for the Cabinet base, Vertical slide, taper turning attachment, metric change wheels, collets etc etc. nearly £3000.

Barry

Just found the price list from 2011

330TR (Toolroom Lathe) £14,750 + Vat

Edited By Saxalby on 03/07/2015 20:19:41

[JasonBModerator @jasonb]

I thought the TS was a Trainer with Screwcutting gearbox, the TR is the better Tool Room spec

[Nitai LeviParticipant @nitailevi73768]

Posted by John W1 on 03/07/2015 17:50:01:

You would be talking a lot more than 4 times the price.

I'm sure prices and lathes available vary in different countries/areas. I wasn't randomally saying that, I was referring to actual lathes I considered before buying the Sieg.

I imagine that old Boxford (or a new one) is good but I haven't heard of that lathe and I don't know if anyone here even has one. They were possibly never imported here, I have no idea( and it's too big anyway). I was also specifically talking about the amount of time I would have to mess with adjusting it and not necessarily the accuracy of the lathe. With the exception of the height of the tail the accuracy of my lathe is completely acceptable to me. It just took me so long to adjust it…

I was looking at used lathes too and found an old Schaublin but it was too big. I think it cost $6,000.
There were three new lathes I considered and spoke with people who own them. They do cost 2.5 to 4 times as much as the Sieg SC3 (which by the way costs more here than in the USA or UK, but shipping from abroad wasn't an option). I didn't buy any of them because of size or some compromises.

[PeteParticipant @pete41194]

Nitia,

I can fully understand your frustration of having to rework what should have been correct right from the factory. With the almost universal use of CNC on production machine tools even in China, or at least the bare minimum of today's cheap Chinese built, but still fairly high accuracy DRO's on any manual machine's that might possibly still be used in a production environment, plus the standard world wide use of jigs and fixtures to speed up production. It is more than inexcusable today that even those cheap machine tools are still being made this inaccurate. Even a 5 second check with an in house shop built gauge would show when an adjustment or new tool tip is required. I honestly can't logically figure out how they can still make any of the cheap machine's that inaccurate today. With the volume there producing, then just add $5 to the price and start checking and using some gauges to show when and where there's a problem developing long before we start seeing what we have been as the end users.

But your certainly not alone with having problems with Seig machines. I spent over $4000 on a Sieg C6, there X2 mini mill, and a lot of accessories. My tailstock pointed uphill over .009" in 2" . Add on a drill chuck, plus the length of a standard drill, and that drill tip was about .025" high or higher with the tailstocks barrel extended. It was impossible to use any center drill because the drill tip was so high the tips would instantly get ripped off as soon as they touched a spinning work piece. Reaming from the tailstock was obviously not going to happen without a very tapered but reamed hole. The additional tee slotted milling table was severely warped enough to easily see it visually. And the cross slide's surface was incorrectly ground over .003" in both directions. So it was impossible to do any accurate milling or between centers boring with the work bolted to the cross slide the way the machine was originally machined, ground and built. So to again use some logic, Seig either has very poorly trained and incompetent employee's, or there management could care less about there customers. I certainly won't ever buy another Seig machine no matter how much they improve there quality control in the future. My comments here may or may not affect company's such as Arc Euro who I do think is a very good company, and who will stand behind what there selling. But I didn't buy from them, and I can only comment on what my personal experience has been with Seig machines.

And I'm certainly not expecting Schaublin quality or accuracy at that much cheaper price. I am expecting the basic machine alignment's to be at least much more correct than what I found so the machine was usable without having to correct the factory errors. You could hardly do worse even on purpose. But it was that machine that forced me into educating myself about what's really involved with the correct yet basic lathe alignments. I do think you don't see all that many complaints on these forums about those alignments because most think what they've bought has to be correct, so most probably won't check like you have.

Pete

[David CambridgeParticipant @davidcambridge45658]

A few more pictures to say how I convinced myself to stop worrying about this – of course others may be different but for me I concluded my lathe was good enough for the things I wanted to do. As a very wise man said earlier in this thread ‘don't worry so much.’!!

Draw a circle 5 mm diameter

 

Draw another identical circle on top of it

 

Displace one circle up by 0.15mm

 

Measure the distance between the two circles on the horizontal and where the cutting tool is

Edited By David Cambridge on 04/07/2015 06:59:26

[JasonBModerator @jasonb]

David as you have shown its not so bad when turning. Now put a 3mm reamer in the tailstock chuck and see what happens, the top edge of the reamer will be high by 0.15mm so in effect acting like a boriong bar taking a 0.15mm cut as it tries to straighten itself so your hole will be double that at 3.3mm which is certainly more of a problem than the O.009mm on dia whan turning.

Nitai, out of interest I had a look at teh test sheet on my Warco 280, for the No 1 test shown on Johns sheet mine shows 0.05mm and does not give me noticable problems.

[Author]

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