Talk:Lathe center
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Live or Revolving??
[edit]Their appears to be differing usage of the term live center or revolving. The claim has been made that a live center does not run in its own bearings, but instead is mounted in the spindle where it is free (live) to rotate. A search on the web using the two terms indicates that revolving centers may be a UK (british) term which could explain why live center is "free" to take an alternative meaning.
In Australia the term Live centre refers to a center running in its own bearings - Piper tools has been manufacturing live centres since around 1937, and still does as this listing shows. I've referenced this usage by pointing to the Fitting and Machining reference book used by Victorian apprentices since the 1980's and evolved from a series used since early 1970's. A search of The State Library of Victoria lists it as
Title: Fitting and machining / general editor: Ron Culley. Publisher/Date: Collingwood, Vic. : TAFE Publications Unit, c1988. Description: xxxiv, 639 p. : ill. ; 29 cm. Notes: Previously published as 3 separate vols. ; repr. with minor corrections. Includes index. Subject(s): Machine-shop practice. Other author(s): Culley, Ron. Victoria. TAFE Publications Unit. ISBN/ISSN: 0724138196 : Status: Available Location: Information Centre R Call Number: 670.42 F56 (1988)
I've included the alternate meaning within the page but have requested a citation for it as I can't find one, nor am I familiar with the term, to know where to look — Graibeard (talk) 13:06, 12 July 2006 (UTC)
More on Live or Revolving
[edit]I believe that the photo at the top of the page is incorrectly labeled. Here is why. If you look at the evolution of the center in general terms it started out life as just a center.
If you now take that same center and place it in the head stock it is said to be LIVE (rotating with the spindle). If you take that same center and put it in the tail stock it is now motionless or DEAD. Dead centers create lots of issues with wear and heat build up so the revolving center was created. That is, a center were the front half is able to rotate about its center line on its own bearing set, but, the rear of the center (Morse Taper) is motionless or dead. This is what I was taught, , 20 years ago when I did my time as a Toolmaker. If this is correct and based on logic it is, then this and several other articles in Wikipedia need a re write. Note that this terminology is not Lathe exclusive for instance the same definition of use applies to a Cylindrical Grinder. — Preceding unsigned comment added by Kiwiguy111 (talk • contribs) 2014-03-14T04:50:08
- It's not that either classification is wrong—just that they coexist. We should ideally edit the coverage to mention both classifications. Graibeard already laid out the difference in the comment above from 2006. He mentioned that it is normal in Australia to reserve "live" only to those that run in their own bearings. I can confirm that that classification is also common in the U.S. The alternative way of looking at it (that a dead center when put into a headstock becomes live) has its own internally valid logic, too, but a lot of people don't use the terms that way. I'd say the reason why is that the distinction between dead and live was invented to talk about what was happening at the tailstock, anyway (not the headstock). There was a time when no centers had their own bearings, so all centers at the tailstock were what later generations would call "dead". Then people developed ones with their own bearings so that a tailstock center could rotate with the work. So adjectives became needed to differentiate the types. That's where the dead-vs-live distinction came from. Headstock centers have always rotated with the work and have always not had their own bearings. IMO it makes a lot more sense to just say "center" and not even talk about dead vs live at the headstock end. Anyway, the article could try to cover/explain the difference in usage. — ¾-10 13:03, 14 March 2014 (UTC)
spring
[edit]i have seen spring centers being sold in several machining catalogues but am not sure what exactly they do. I think that this article should explain what they are and their use. —The preceding unsigned comment was added by Brandizle326 (talk • contribs) 00:41, 21 March 2007 (UTC).