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Evan
08-26-2005, 04:40 PM
"Schlesinger limits of accuracy"

I ran into this term today. I can't find much about it. Does anyone know exactly what it means and how it originated?

John Stevenson
08-26-2005, 06:09 PM
Even,
I have some books on this, I'll dig them out over the weekend.
Ironically enough the Russians were very big on these.

I have just cleared some papers and books out from Myfords old Development Engineer who has recently died.
They used a set taken from some Russian books as well.

John S.

CCWKen
08-26-2005, 07:40 PM
Schlesinger is Russian?

Kobzdej is Russian! http://bbs.homeshopmachinist.net//biggrin.gif

JCHannum
08-26-2005, 09:49 PM
Norman Atkinson mentioned it here the other day;
http://bbs.homeshopmachinist.net//Forum1/HTML/013190.html

Evan
08-26-2005, 11:26 PM
According to Norman's reference the book was published in 1961. Yet, the reference I saw on the lathes.co.uk website refers to a Robot lathe from the 1930s built to Schlesinger limits. Perhaps this is just a later edition? Still, I am very curious just what these limits are and how they are measured/determined.

John Garner
08-26-2005, 11:50 PM
Dr. Georg Schlesinger wrote "Testing Machine Tools", which is the very best book on that subject I've ever seen . . . and I'll include Moore's "Foundations of Mechanical Accuracy" and Connelly's "Reconditioning Machine Tools" among the books surpassed.

Schelinger wrote his book long enough ago that his testing methods rely on conventional instruments and methods rather than laser interferometers and electronics, and from what I can tell the English translation didn't loose much, in anything, when compared to the original.

Copies of "Testing Machine Tools" are hard to come by, being a very specialized publication that's been out of print for a long time now, but your library can probably come up with a copy on an interlibrary loan.

It's worth the effort to track down . . . and worth the effort of photocopying.

John

Evan
08-27-2005, 01:13 AM
Now we are getting somewhere. Thanks.

I found this.

http://www.elsevier.com/wps/find/bookdescription.librarians/15561/description#toc

John Stevenson
08-27-2005, 03:27 AM
Evan,
Sorry for the miss spelling of your name, didn't spot that until today.

Schlessinger wasn't Russian it's just that the Russians were big on conforming to these limits.

From the book link put on by John Garner.

"Contents
The machine tool under load. Measuring equipment and methods. Surface quality. "

And these photo's of a Myford Mini Kop lathe under test.

http://img.photobucket.com/albums/0903/registered_user/minikop1.jpg

http://img.photobucket.com/albums/0903/registered_user/MiniKop2.jpg

They certainly put a lot of effort in behind the scenes.

I'll try to sort the books out but I have some computer problems I will have to fix this weekend so I may be AWOL for a while.

John S.

Tin Falcon
08-27-2005, 05:39 AM
Interesting! found this link to a pdf file from an old model engineer magazine July 1955 on lathe testing nt the moden methods butdoable for the HSM shouldwork on my old south bend.
http://www.wrathall.com/Interests/machining/Testing%20lathe%20for%20accuracy.pdf

Peter S
08-27-2005, 08:35 AM
Evan,
Not sure if you have seen them, but some lathes came with a Schlesinger test sheet, my Graziano has one, probably two pages long.

It is a list of tests, each test is described along with the min or max condition. The result of each test is written in pen in the blank space provided, signed by the inspector etc.

I don't have the tests to hand, but it checks how parallel headstock is to ways, etc etc

I always thought these were a set of standard tests, you can find the same test sheet supplied by different manufacturers.

nheng
08-27-2005, 08:52 AM
Thanks for the link Tin Falcon. It has some interesting alternative ways of doing things.

Had to read the cross slide vs ways test 4 times to get it straight in my mind. I think it assumes that the cross slide is long enough to pass fully beyond the center and to the opposite side of the faceplate. The method can be adjusted of course, for one with shorter travel. Den

Mcgyver
08-27-2005, 08:03 PM
a German

The law, to quote a renowned univeristy law prof, is not concerned with right and wrong but is simply intended to maintain the status quo.

I'm reminded of that by this book. It's old, it's out print book and because of rapidly changing technology every day it will be of less and less commercial interest, yet the reason we can't download from some univestity ftp site is the copyright law. Too bad, stupid, and nothing to do with right and wrong.




[This message has been edited by Mcgyver (edited 08-27-2005).]

Evan
08-27-2005, 10:42 PM
He could have put it in the public domain. Unfortunately, he didn't. He died the year I was born.

http://www.tu-berlin.de/presse/125jahre/festschrift/schlesinger_e.htm

John Stevenson
09-04-2005, 07:13 PM
Found the book, or rather parts 1,2 and 4 of a 4 volume set, possible never had vol 3.
Full title is

Acceptance Test Charts for Machine Tools.
Schlesinger Limits.
Part 1
Prepared by the Research Department of the Institution of Production Engineers, March 1940.

Bit of a forward and intoduction then it's all master charts for different machine tools, in classes and grades with the tolerances.

Still having some computer problems so this is the best I can do until I get the OCR re-installed

http://homepage.ntlworld.com/stevenson.engineers/lsteve/files/standards1.jpg
http://homepage.ntlworld.com/stevenson.engineers/lsteve/files/standards2.jpg

Evan
09-04-2005, 07:56 PM
Thank you, Sir John, very informative.

I especially like the part:

"...Should assemble these parts into the machine in such a way that that the variations within the permitted tolerances are equalised".

This is an especially difficult task as it means taking precautions to avoid tolerance stacking.

Norman Atkinson
09-05-2005, 01:26 AM
Sir John- of the Green Wood,

As you are having computer problems- there is a club, and pulling out remaining hair is immediate acceptance- I still have the
" Testing of Machine tools" from our Public Library.

It runs to 100 pages- and scanning will be a complete nightmare.

I have written to Evan- offering to copy bits but no reply.

This book- I have to add- is actually part of the Reference- Not to be taken Away) section.

Your ideas would be invaluable.

I have the honour to be,
Sir,
Your Obedient Servant.

Whiteadder.

Evan
09-05-2005, 09:58 PM
I'll get back to you Norman.

In the mean time here is a quote from Lady Whiteadder:

"Cold is God's way of telling us to burn more Catholics"

Norman Atkinson
09-06-2005, 01:40 AM
Evan!

Oops! I hadn't even remembered that there was a Lady Whiteadder. The Rivers Blackadder and Whiteadder join just North of here. Five miles from where I was born, "Blackadder" was born.

Before my good Catholic friends do me a final mischief, I must apologise wholeheartedly for any adverse remarks from one of the few survivors of the Druid massacres.

Apologies alround. Shame on you, you Welsh wizard.

You may have missed the fact that Blackadder went to the marriage of a Catholic recently. At some point, we are going to get a real Lord Blackadder!
The Future Lady B. is*******************
Indeed!
N.