Why Use A Dead Center Instead of Live Center?

[Splat]

With technology and manufacturing being pretty top notch these days it would appear live centers have come a long way in accuracy and reliability since their inception. I can understand using a dead center for want of most accuracy. However, the majority of work most home machinists do don't require that level of accuracy, unless I'm mistaken as to the accuracy live centers exhibit. So why not use a live center instead of a dead center?

 

[swatson144]

I use the dead center on the live end turning between centers. Or the dead center goes in the spindle taper so it turns with the work and the live center in the tail stock. Every once in a while you need a special shaped center for a one off and making your own dead center is the fix.

Steve

 

[PurpLev]

you'd want to use a dead center on the headstock to transfer the friction to the part being turned.

Another good use of a dead center in the tailstock is with a half (dead) center which allows you to face almost to the center of the part being faced with the center providing support.

 

[GK1918]

question answered, example my big GK takes a MT 5, I have 1in drill chuck, live bull live center of which
is as big as the commom headstock chucks. Rhom I think, just take a guess $$$$$ and so much I keep
these in the large zip lock baggies with an oil soaked rag and in a plastic box. I would like a set for
my SB9 lathes but I got no deep pockets now, but dead centers work well on small machines and I
make my own thats why S.B.s have a dauber.

 

[Splat]

Thanks guys. I picked up 2 deads to start me on my lathe adventure. A live center may be down the road but for now it makes sense to get the deads.

 

[Splat]

If you've never used a dead center, there are a couple things to aware of. You do need to use grease for lubrication. Many people just use an automotive EP grease. I use an EP wheel bearing grease myself. But you can get a proper tube of grease for use with dead centers, (I used to get it from McMaster-Carr). I think there is a noticeable difference. Particularly at higher speeds.

Good timing, Dalee! I was just thinking about what type of lube to use with the dead centers.

You also kind of need to develop a feel for just how much pressure to apply with the tailstock. Too little and you get deflection and chatter. Too much and you force the grease out and everything heats and you can even burn and weld the part to the center. And because of the tendency to heat, keep an eye or rather keep in touch with your part. When it feels too hot to touch, stop and take a break to let it cool down. Patience is important here.

I figured as such, but haven't done any work on the lathe yet. I'm still refurbing it. I'm just slowly buying the accessories/tooling I'll need to get going.

Did you order carbide tipped centers or bearing steel?

I actually bought the carbide tipped deads from Tools4cheap. For now they should be ok...I hope. FWIW, I plan on practicing/starting my lathe skills on 6061 aluminum since I have some laying around.

 

[aametalmaster]

I use a dead center for smaller dia parts where my live center is too big to get my lathe tooling in there to cut...Bob

 

[core-oil]

For turning with my dead centre (not very often) for a lubrication, i use ordinary cooking fat or lard, comes in a block from the supermarket, This stuff is excellent for clogging your arteries! I take a little of that goo, &mix it with some powdered graphite, It works for me, But i do not force my centres with excessive pressure or allow to run hot, After finish turning clean of all traces from work &machine with a piece of kitchen roll

 

[Tony Wells]

Non-bearing centers also have the advantage of never introducing bearing noise into the finish. Even a good bearing center in time will wear enough to loosen up the bearings. The better ones can be rebuilt, but not an issue with non-bearing centers.

 

[Abom79]

For me the only times I really sue a dead center are for...
-in the headstock for turning between centers
-in the tailstock when straightening shatfs
-when indicating a part using a punch mark or centerhole.

If your turing a shaft, a live center is the way to go.