Tools for turning between centres

[Kit White 1Participant @kitwhite1]

[Kit White 1Participant @kitwhite1]

Hello all, I'm new to lathes and have recently purchased a Myford ml7, of which I am trying to slowly accumulate a basic set of the necessary tools I will need for hobby use. With regards to turning between centres, exactky what tools/accessories do I need? Two centres, one live, one dead (tailstock needs the dead centre, correct), carriers, faceplate etc?

On reading up on this, the work appears to turn against the dead centre as it stays still, but does this not ear the taper out quickly?

[Thor 🇳🇴Participant @thor]

Hi Kit,

If you use a non-revolving centre in the tailstock you use a lubricant in the centre hole, and don't use much pressure from the tailstock.

Thor

[John HinkleyParticipant @johnhinkley26699]

If I have read your posting correctly, you've got your centres the wrong way round. The dead centre goes in the headstock, with a faceplate on the spindle nose. The work is positioned on the centre and the other end is supported by the live centre in the tailstock and a lathe dog provides the drive from the faceplate to the work. This way, there is no relative movement between the work and the dead centre, thus no wear. You would be well advised to do some reading on basic lathework before attempting any actual machining, if only to minimise the risk of injury. These machines can – and will – bite the unwary!

Be careful and good luck,

John

[VicParticipant @vic]

Posted by John Hinkley on 12/12/2015 18:59:53:

If I have read your posting correctly, you've got your centres the wrong way round. The dead centre goes in the headstock, with a faceplate on the spindle nose. The work is positioned on the centre and the other end is supported by the live centre in the tailstock and a lathe dog provides the drive from the faceplate to the work. This way, there is no relative movement between the work and the dead centre, thus no wear. You would be well advised to do some reading on basic lathework before attempting any actual machining, if only to minimise the risk of injury. These machines can – and will – bite the unwary!

Be careful and good luck,

John

Good post John, couldn't have put it better myself!

[Speedy Builder5Participant @speedybuilder5]

Not quite, the Dead centre goes into the headstock spindle and the live or rotating centre goes into the tailstock. You can use a Dead centre in the tailstock, but you must lubricate it well and not use too much end loading, check how warm it is running and stop, re-lubricate. If like me, you run a centre too hot and "weld" it to the component, chuck the centre into a fire until red, reduce the heat slowly and then mount in the headstock and re-machine the centre. Then re-harden it. Not a perfect idea, but gets you out of a tight spot – best not to ruin a centre in the first place.
Carriers or dogs can have a straight tang or bent. Straight tang dogs will be driven by a peg on the faceplate. Bent tangs dogs will be driven by a slot in the faceplate.
Question, why are you turning between centres, most lathe work is gripped in the chuck at one end.
As for tools, start with High speed tools then you can change profiles and re-sharpen with a normal bench grinder. Carbide tools can chip quite easily when you are learning.
Choise of material is paramount – if you pick up any old material you can be put off due to poor surface finish. If possible get free cutting material if it suits your application. Good luck and keep asking questions.
BobH

[BazyleParticipant @bazyle]

sigh. the one in the headstock is called the live centre because it moves. It may be made of unhardened steel so that it can be turned true before stating for maximum accuracy but this is not always necessary.

The one in the tailstock is dead because it does not move. You can also use a revolving centre here to reduce the anxiety of it getting too hot and having a problem. However in the antipodes some people call a revolving centre a live centre and like to confuse everyone by talking about a live centre in the tailstock.

[John HinkleyParticipant @johnhinkley26699]

Well, that's put me in my place! See what happens when you are self-taught from books. Better listen to those who know what they are talking about. My warning about safety, I stand by, though.

John

 

Edited By John Hinkley on 12/12/2015 19:54:51

[Kit White 1Participant @kitwhite1]

Thanks guys, turns out I had the correct undertanding first time round, I shouldn't doubt myself so much!! I am reading through the brilliant The Amateurs Lathe by L.H Sparey, but am just trying to put the meat on the bones, as it were.

My lathe already has the dead centre it came with, so its a carrier, faceplate and live/revolving centre I need.

[Peter KroghParticipant @peterkrogh76576]

I didn't think that putting a dead center in the spindle made it a live center. Maybe there's a bit of magic that happens to give it life.

Pete

[jason udallParticipant @jasonudall57142]

This comes up from time to time.

In catalogues” live” centers are the ones with bearings so that they spin…consequently made for the tail stock

But.
Back when turning between centers was the more common practice ..
The live center was the one that spins with the head stock ( and part)..live because it was driven.
The other center in the tail stock might be called dead.

These centers are still called dead and some times find a home in the headstock taper as “live” centers.
As has been said often the center in the headstock are unhardened to facilitate truing up in situ. . Plus being driven with the part they don’t need to be.

“Dead” centers are supplied hardened
They are also available as half centers which allows some access to the end of the part for facing etc.
Sorry but the terminology has become muddled..
Live with it

[Chris Evans 6Participant @chrisevans6]

If you do buy a "Live" or as I call them "Running" centre, consider one with an extended nose length. It will save having to move the compound slide around to about 30 degrees to get to the end of the work on some occasions.

[Peter KroghParticipant @peterkrogh76576]

Makes sense jason. I came along in the mid '70s and the 'running' center was the prevalent tail stock center so I never was exposed to the 'old' terminology.

Pete

[VicParticipant @vic]

Posted by jason udall on 13/12/2015 10:05:36:
This comes up from time to time.

In catalogues" live" centers are the ones with bearings so that they spin…consequently made for the tail stock.

Agreed. Terminology may have changed but we don't live in the past.

Ask any supplier for a live centre and you'll get one with bearings. Once the old ones pass it will all make sense.

[jason udallParticipant @jasonudall57142]

Vic.
I think that was my point. The correct term ..well I couldn’t say..

current usage..see catalogue for details.

[Ian S CParticipant @iansc]

For a couple of quid extra you can get a dead centre with a carbide tip that will stand the wear better than a hardened carbon steel one, but a good running centre is a great help. There is one in Sparey's "The Amateur's Lathe" that would be a good exercise on the lathe, I made a few when I first got my lathe, sold them all, and bought a Skoda running centre (it was wood turners that bought my own make).

Ian S C

[Neil WyattModerator @neilwyatt]

It helps to remember that the most primitive lathe was a 'dead centre' lathe, with a non-rotating point at each end (like a pole lathe or watchmaker's turns).

The expression 'rotating centre' and 'fixed centre' can be helpful.

Neil

[Kit White 1Participant @kitwhite1]

Ok, glad I asked now. I guess times have changed since The Ameteurs Lathe from 1948, hence my confusion. Is it better to get a revolving centre like this or get a good used old one? How do these cheaper, newer ones compare?

[VicParticipant @vic]

Posted by Neil Wyatt on 14/12/2015 14:49:10:

It helps to remember that the most primitive lathe was a 'dead centre' lathe, with a non-rotating point at each end (like a pole lathe or watchmaker's turns).

The expression 'rotating centre' and 'fixed centre' can be helpful.

Neil

It's actually much easier on wood turning Lathes as you have a Drive centre in the head and a Live centre in the tailstock. In fact that also applies to MW lathes if you're using a four point Drive centre in the head!

[Chris Evans 6Participant @chrisevans6]

Kit, I would buy the new centre. There is no way of knowing what work or abuse a used one has had until you use it. I doubt if you will do enough work to wear the new one out.

[Bodgit Fixit and RunParticipant @bodgitfixitandrun]

In the days of my yooth, if I remember correctly we used bees wax or tallow to lubricate the dead centre in the tailstock. It smoked a lot and stunk.

[Maurice Cox 1Participant @mauricecox1]

As other contributors have said, the live centre is unhardened so that it may be machine true in situ. The live centres supplied by Myford were identified by having a ring turned on the body, while the dead centre was plain.

Maurice

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