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I am getting way ahead myself and looking at plans and examples of treadle lathes. One in particular was talking about his dead centre and how it was not as good as a live centre for his treadle lathe (which he states is due to friction).

Dead Centre Image still (of a dead centre) from linked video

My related and hopefully not too broad questions are what are live and dead centres? What are the functional differences between a live/dead centres? Would there be a practical reason to choose one over the other?

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what are live and dead centres?

To put it simply a dead center is just that - dead. It has no moving parts. It is really nothing more than a metal shaft with a point.

dead center
(source: parts-recycling.com)

A live center is similar, but the shaft has a bearing that allows it to turn. For example, in my lathe, the tail stock has a Morse taper, in which I put a live center. The tenon fits in the Morse taper, and it has a bearing assembly with a conical point on the other end that is free to spin.

live center
(source: Z Live Center)

What is the functional differences between a live/dead centers?

The live centers are great in that they don't have really any friction and allow your piece to spin freely. Dead centers are more often found in treadle or pole lathes, which are often built to be "period correct." The use of a modern live center would be anachronistic in this case. A turner would use the dead center with some grease or oil on the point to keep it from squeaking in use. I've also heard that ear wax or the skin oil on the side of one's noise was historically used, but don't quote me on that.

Would there be a practical reason to choose one of the other?

If you're not worried about being "period correct," the live center is really the way to go. I think most modern lathes ship with one standard, anyway.

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Live centers have bearings..which could could run out of center..for metal turning purposes this would not be an accurate enough center to use if you were dealing in tenths...ie bearing diameters etc.. .0001 tolerances..but if its a quality enough one and you had high rpms you would not have much choice then.. dead centers..even with grease..and a high enough rpm and friction could actually weld the metal to the center..or in the case of wood start it on fire or something I would think.. I was a machinist not a woodworker..but its the same tool and I would think these kind of issues would still apply..

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Live centres are driven under power so if it's in the chuck or headstock it's a live centre, a dead centre isn't powered so a centre in the tailstock would be considered a dead centre of its a bearing centre or a solid centre it doesn't matter, bearing centres are never really live centres because they wouldn't be able to drive

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    I'm sorry you are wrong. You are talking about the differences between a DRIVE center and a live/dead center, live/dead centers are both in the tail stock, a drive center is in the head position. – bowlturner Jun 20 '18 at 15:34

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