Standards for machine tool errors

[John PurdyParticipant @johnpurdy78347]

[John PurdyParticipant @johnpurdy78347]

Could someone tell me the name of the standards for errors in the alignment of machine tools. I believe they are based on ones set out by a (German I think, name starting with an "S"?) person many years age. I recall an article in one of the mags dealing with them but can't find it. I've searched the various indexes without any success, but obviously I'm not using the right search criteria. Thanks.

John Purdy

[JasonBModerator @jasonb]

Schlesinger

[John PurdyParticipant @johnpurdy78347]

Jason

Thanks, that's the name I was trying to think of. German or Swiss? Now to see if I can find the article.

John

Edited By John Purdy on 30/11/2017 19:38:38

[Peter G. ShawParticipant @peterg-shaw75338]

Could it be ME 04 Oct 1996 etc (4 issues) by Tubal Cain (T.D.Walshaw) in a series odf articles about testing & alignment.

Also ME 18.Oct 1991. Prof D.H.Chaddock explains about Schlessinger limits.

Peter G. Shaw

Edited By Peter G. Shaw on 30/11/2017 19:56:12

[Michael GilliganParticipant @michaelgilligan61133]

A question for Neil:

Is it permissible to post a link to a PDF copy of "Testing Machine Tools" seventh edition.

If not; I shall of course refrain.

MichaelG.

[not done it yetParticipant @notdoneityet]

Send it by PM? No need for 'please Sir'.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by not done it yet on 30/11/2017 20:10:57:

Send it by PM? No need for 'please Sir'.

.

It was a simple question, related to this site's 'Terms and Conditions'

I would really prefer not to P.M. everyone that might want a copy !

Much simpler to post a link … if so-doing does not breach Copyright.

MichaelG.

.

Of course, those with a nose for searching should have already found it.

Edited By Michael Gilligan on 30/11/2017 21:05:44

[fishy-steveParticipant @fishy-steve]

Hi John,

Is the article your looking for "No limits: George Schlesinger" by Alan Bester.

MEW No 246. Autumn 2016

[David Standing 1Participant @davidstanding1]

Posted by not done it yet on 30/11/2017 20:10:57:

Send it by PM? No need for 'please Sir'.

Chill pill required

[Neil WyattModerator @neilwyatt]

Posted by Michael Gilligan on 30/11/2017 19:53:27:

A question for Neil:

Is it permissible to post a link to a PDF copy of "Testing Machine Tools" seventh edition.

If not; I shall of course refrain.

MichaelG.

Technically it is in copyright in the UK and the rest of the EU until May 2019 IIRC and the copyright is owned by the publishers of Machinery's Workshop.

I tried to get permission to publish decent extracts last year and was unsuccessful.

The author of the article in MEW is in South Africa where it is out of copyright as their law is different…

[Michael GilliganParticipant @michaelgilligan61133]

IPosted by Neil Wyatt on 30/11/2017 21:48:28:

Posted by Michael Gilligan on 30/11/2017 19:53:27:

A question for Neil:

Is it permissible to post a link to a PDF copy of "Testing Machine Tools" seventh edition.

If not; I shall of course refrain.

MichaelG.

Technically it is in copyright in the UK and the rest of the EU until May 2019 IIRC and the copyright is owned by the publishers of Machinery's Workshop.

I tried to get permission to publish decent extracts last year and was unsuccessful.

.

Thanks, Neil

It's as I assumed.

MichaelG.

[John PurdyParticipant @johnpurdy78347]

Thanks to all who have replied. That's the info I was looking for (I knew someone here would know the answer ! )

I have dug out the three articles and the MEW one and the ME Oct '96 articles are the ones I remember.    This was instigated by a request from a friend here who is trying to measure the alignment of his lathe's headstock and tailstock and asked if I knew of any accepted standards. Thanks again.

John Purdy

 

Edited By John Purdy on 30/11/2017 23:12:35

[David ColwillParticipant @davidcolwill19261]

Posted by Michael Gilligan on 30/11/2017 21:51:07:

IPosted by Neil Wyatt on 30/11/2017 21:48:28:

Posted by Michael Gilligan on 30/11/2017 19:53:27:

A question for Neil:

Is it permissible to post a link to a PDF copy of "Testing Machine Tools" seventh edition.

If not; I shall of course refrain.

MichaelG.

Technically it is in copyright in the UK and the rest of the EU until May 2019 IIRC and the copyright is owned by the publishers of Machinery's Workshop.

I tried to get permission to publish decent extracts last year and was unsuccessful.

.

Thanks, Neil

It's as I assumed.

MichaelG.

Or of course one can simply search Google for "Testing Machine Tools Schlesinger" and download it!

David.

Ps Thanks Michael for bringing this to my attention.

[Neil WyattModerator @neilwyatt]

Yep, but as a publisher we have to avoid publishing links to pirate copies.

We get very cross when people pirate our publications and it would be double standards to encourage such things.

That said the internet is so ambiguous and its rarely clear what is OK and what isn't, especially with old books and manuals.

Neil

[Russell EberhardtParticipant @russelleberhardt48058]

This raises interesting questions.

Copyright on published material in Europe lasts, in general, for 70 years after the author's death. However in, for example, Australia and Canada it lasts for 50 years after the author's death.

As Dr; Schlesinger died in 1949 it is perfectly legal to download a copy in Australia so what happens if get a friend to download it legally there and then legally email me a copy? If it is downloaded in Australia does it then become copyright free and freely available anywhere?

Clearly copyright law worldwide needs to be brought up to date with the internet age.

Here in France I could watch BBC television programs through the internet. However the BBC only have the rights to transmit many of their programs to UK viewers. Again the laws are unclear and archaic.

Russell;

[Neil WyattModerator @neilwyatt]

Posted by Russell Eberhardt on 01/12/2017 14:57:57:

This raises interesting questions.

Copyright on published material in Europe lasts, in general, for 70 years after the author's death. However in, for example, Australia and Canada it lasts for 50 years after the author's death.

As Dr; Schlesinger died in 1949 it is perfectly legal to download a copy in Australia so what happens if get a friend to download it legally there and then legally email me a copy? If it is downloaded in Australia does it then become copyright free and freely available anywhere?

The law is simple enough, it becomes an illegal copy once it reaches the EU, just like a copy of a physical book printed abroad then imported.

Neil

[Nick HulmeParticipant @nickhulme30114]

Posted by Neil Wyatt on 01/12/2017 16:12:05:

The law is simple enough, it becomes an illegal copy once it reaches the EU, just like a copy of a physical book printed abroad then imported.

Neil

Is this the case also for second hand goods not for sale or commercial use which were initially purchased where legal?

[Neil WyattModerator @neilwyatt]

Posted by Nick Hulme on 01/12/2017 16:42:45:

Posted by Neil Wyatt on 01/12/2017 16:12:05:

The law is simple enough, it becomes an illegal copy once it reaches the EU, just like a copy of a physical book printed abroad then imported.

Neil

Is this the case also for second hand goods not for sale or commercial use which were initially purchased where legal?

Probabl;y, the thing about copyright theft is it is so prevalent and 'socially acceptable' (who didn't have a pile of cassettes recorded by their mate in the 80s?) it's really only practical and cost effective to go after the mass producers and distributors of rip-offs -such as ebay selllers of pirate DVDs. Taking one person who gave their mate a scan of a book doesn't do much to protect your profits and the damages could hardly cover the costs! But it does make it increasingly difficult to make a sensible return on 'creative works' from magazines to books to music etc.

One irony is that despite claims live music was dead fifteen years ago, music piracy has made live performance the way most bands make their money now – the albums promote the tours rather than the other way round!

[HopperParticipant @hopper]

Posted by Russell Eberhardt on 01/12/2017 14:57:57:…

…As Dr; Schlesinger died in 1949 it is perfectly legal to download a copy in Australia so what happens if get a friend to download it legally there and then legally email me a copy? If it is downloaded in Australia does it then become copyright free and freely available anywhere?

Actually there is a very handy loophole in Australian copyright law, which is based on British law so may apply there also. If a book is out of print and has been for some (unspecified) time, it is perfectly legal to make and possess a copy of it for your own research purposes. "Research purposes" has been legally tested and found to include research by private individuals for their own private purposes.

Even with books still in print, you are allowed (in Aust.) to copy parts of it — usually regarded as a chapter or two, for research purposes.

In both cases though, you are not then allowed to give further copies to other people. It is exclusively for your own use only.

With the Schlesinger book, a Google search for its title turns up various copies of it available for download on various internet sites, some of them commercial, some of them scams and some of them not. All of them technically illegal if they do not have permission from the copyright holder, which I doubt in most cases.

But I would not get too carried away with Schlesinger limits for a home hobby lathe. If you can get your alignment within one thou of an inch you are doing well, on either a worn British/American/Aussie lathe or a new import model.

And final test should be a turning test as perfect static alignment means almost nothing if the machine is flexing and moving under cutting loads, as small lathes and worn lathes always do.

Edited By Hopper on 02/12/2017 02:06:09

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Hopper on 02/12/2017 02:00:42:

But I would not get too carried away with Schlesinger limits for a home hobby lathe. If you can get your alignment within one thou of an inch you are doing well, on either a worn British/American/Aussie lathe or a new import model.

And final test should be a turning test as perfect static alignment means almost nothing if the machine is flexing and moving under cutting loads, as small lathes and worn lathes always do.

.

Very fair comment, Hopper

That said, however; I would commend particularly the seventh edition [revised by Koenigsberger].

Koenigsberger's Preface, and Schlesinger's own Introduction usefully explain the principles of the testing.

… Whilst the figures may be of largely 'academic interest', the book remains a very good reference.

MichaelG.

.

P.S. on a perhaps ironic note: I purchased my hardbound copy from the local College Library; where it was presumably being discarded as obsolete.

[Neil WyattModerator @neilwyatt]

I've had a note to say "There was a good article in ME. Page 397 of the 4th October 1996 gives the checks needed as well as well as the respective limits, this second table also gives the results for a 31/2" modellers lathe as well as a 65 mm instrument makers lathe".

Neil

[Neil WyattModerator @neilwyatt]

There are two approaches to machine testing. There's the Schlesinger approach which measures the machine in a more or less static condition and require errors to be in the directions which would compensate for normal cutting forces.

The second approach is the 'cut and try' one where a machine is installed and adjusted until it can meet its specified performance.

The first, Schelsinger, approach was developed for situations where there is no control over the final installation – 'it was fine when it left us'.

With large, complex modern machines the second approach is universal as you can't transport a seven-axis machining centre and assume everything will still be in spec no matter how good it was on the factory's 15-ton setting up table. It will always be installed by an expert, possibly from or trained by the manufacturer, and adjusted to give the required 'real world' performance.

In our hobby we are obsessed with how well something is made, not how well it performs. Industry, out of necessity, has moved the other way.

As further aside, it is very hard to say the machine you have doesn't match up to its test certificate as your bench, no matter how rigid, won't be the same as the one it was clamped to for testing.

Neil

[HOWARDTParticipant @howardt]

I concurr with Neil, working most of my life as a designer in machine tools. Standard drilling machines were measured to conform to a set of standards and the measurements taken supplied with the machine. Special machines which were dedicated to producing one particular component were proved out so that the component feature produced were within at least 50% of drawing tolerance for the extent of production test run. Larger multi axis cnc machines were installed and tweeked so that all the axis were within the manufacturers tolerances, then parts produced to verify theory against actual life. Tools, tool holding and component holding were all just as important to ensure repeatability.

Working now on small modeling machines we are more into the way of years now gone by in the main. A person worked on a machine all his life and got to know the foibles of the machine as they both got older. Still being able to produce a part in tolerance when the operator retired although by then the machine may have been well out of the original specification. Having a machine produced to a set of standards does not mean it will produce what you want, static tolerance measurements are totally different to what can be achieved when cutting under load.

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