when do you use a live center instead of a dead center?

Ken from ontario said:
Thank you all for your comments and advice.
I know good tools such as Royal live center costs more money but , $350 for for a Royal ? and that's the least expensive one.
http://www.traverscanada.com/search.aspx?keyword=live+centers
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I would not buy a Royal or any other live center at retail prices. Use what comes with your lathe and watch for a deal on ebay. Brands to look for are Royal, Skoda and Riten (there may be others). Rohm makes good ones, too. Typically, a new Skoda will go for about half what a Royal costs on ebay, like this one:

http://www.ebay.com/itm/SKODA-Preci...944974?hash=item1c85af568e:g:oTQAAOSwSypY-T5C

I would make an offer for $100.00 and see if he bites.

I have an interchangeable tip Royal. Its good to know that they are warranted for life and if you have a new tip, Royal will grind it to suit your specific live center body for free, for life.
 
pdentrem said:
Rotating centers only go in the tailstock as stated earlier. Dead center can go in the spindle or the tail stock.

One advantage to using dead centers is you can make a custom one fairly easily. Once it is cut and ground in the spindle it is accurate while a rotating center is dependent on the quality of the bearings and the other components. I also only use dead centers in our Landis Cylindrical grinder they are the most accurate. We need to be inside of 0.0002" in roundness and when making match sets of rolls for rolling mills, dead centers are the only way to get this kind of accuracy.

Pierre
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+1 on this! Dead centers go in the headstock, because you can easily turn them down to be concentric with the center line of the lathe. No need to worry about runout in the chuck. Instant alignment with the tailstock! Also, turning between centers is a great way to work with long work pieces. Like axles with wheels pressed on. Once I did this a few times, it became my go to method for turning long work in the lathe.

Glenn
 
mikey said:
Nowadays, most of us use live centers for almost all work and yes, a live center goes into the tailstock. There was a discussion not long ago about the nomenclature of dead centers and supposedly the solid centers that go into the headstock are "live" centers and the ones that go in the tailstock are "dead" centers. While interesting, the reality is that most of us use tailstock centers with bearings inside them and we call them Live Centers.

As mentioned, a live center is usually used most of the time because it does not require us to stop the lathe and lube the tip of this center. When using a dead center, you have to stop the lathe from time to time to re-lube the tip of the center and then readjust the tailstock pressure because the work piece will heat up and expand from friction between the dead center and work piece.

So, when is a dead center used? It is most often used when we want the ultimate in accuracy, either to turn a precision work piece "between centers" or when using a test bar to align a tailstock. Otherwise, most of us just use a live center.

Not all live centers are created equal. I use a Royal live center and it is very precise, with no discernable play. Cheap live centers can have enough play to affect accuracy, especially when turning big, heavy work pieces so buy a decent one.

Hope that helps.
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Yeah quite the confusion when the old timers chime in about it. I was taught by an old timer who said dead centers are used in the tailstock & live centers are used in the headstock, meaning when a solid center is used in the headstock or whenever it rotates with the part, it's "live" & when a solid center is used in the tailstock (not rotating) it's "dead". I suppose that is how it was befor ball bearing centers were invented?

That's not how they are called today. Look at any vendor or manufacturer & a live center is a ball bearing center & a dead center is a solid center. That's how I'm used to it & that's how I call them too to avoid confusion despite what I was "taught". I suppose I should stop saying "live" & "dead" and should start saying "roating" or "ball bearing" and "solid" but I don't think I will. :)

mikey said:
I would not buy a Royal or any other live center at retail prices. Use what comes with your lathe and watch for a deal on ebay. Brands to look for are Royal, Skoda and Riten (there may be others). Rohm makes good ones, too. Typically, a new Skoda will go for about half what a Royal costs on ebay, like this one:

http://www.ebay.com/itm/SKODA-Preci...944974?hash=item1c85af568e:g:oTQAAOSwSypY-T5C

I would make an offer for $100.00 and see if he bites.

I have an interchangeable tip Royal. Its good to know that they are warranted for life and if you have a new tip, Royal will grind it to suit your specific live center body for free, for life.
Click to expand...

I'm also a believer of not using cheap live centers. I can't afford a Royal or Riten & never was able score a nice one used. I've been using Skodas & I like them. They're the best bang for the buck for live centers IMO.

If you look in the right places, one can get a Skoda for a very good price. Like that MT2 Skoda in the ebay link for $125, I used to have that same one. Earlier this year, I sold both my MT2 & MT3 Skodas & upgraded to their latest ones. I guess they decided to make a change to them cause so many are copying them. I got MT2 Skoda from MSC, brand new for $116 shipped, it was dropped shipped directly from Sowa.

I also have a couple of live centers from Z Live Center. I'm not sure where they're made but I just assume Asian import and I was very hesitant to buy one from them at first but I have their "CNC Precision Long Spindle" live centers & it's actually pretty nice. I've bought a few things from them & I like the company. Just last week I ordered something, they sent me the wrong item by accident, told me to keep the incorrect item & shipped me the correct item.

img_20170202_131519_943-800x622-jpg.225931
 
Here's a Rohm German made live center I saved in a dumpster dive 28 years ago. It had the word "BAD" written on it with a yellow paint pen when I found it. The center point has a few idiot marks on it, but amazing the runout is "zero". Could use a cleaning, not as pretty as Will's, gets the job done!

DSCN3641.JPG
 
darkzero said:
Yeah quite the confusion when the old timers chime in about it. I was taught by an old timer who said dead centers are used in the tailstock & live centers are used in the headstock, meaning when a solid center is used in the headstock or whenever it rotates with the part, it's "live" & when a solid center is used in the tailstock (not rotating) it's "dead".
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Confusion, that's what I found when searching the net for" live center vs dead center", it seems a lot of old timers are of the opinion that live center should go in the headstock! probably based on the same logic you mentioned above.needless to say the opposite makes more sense to a novice like me but it's good to know both sides of the argument.
 
4gsr said:
Here's a Rohm German made live center I saved in a dumpster dive 28 years ago. It had the word "BAD" written on it with a yellow paint pen when I found it. The center point has a few idiot marks on it, but amazing the runout is "zero". Could use a cleaning, not as pretty as Will's, gets the job done!
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What a find, after watching a few youtube videos , it looks like refubishing/repairing these older live centers is quite common.
 
I'm one of those old timers and I was taught to use live centers in the tailstock EXCEPT when knurling or doing an operation that puts pressure against the center.
 
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