Thread: Turning with a dead centre

Haven't tried it so I can't comment on how well it works. For slimlines etc though you could turn up your own bushings from acrylic. The inside diameter of the tubes is 1/4"

Peter

Dave to heck if the mandrel is out of kilter roll it along a known flat surface shaft only that way you'll see if the M2 tapper lashes about. You could be over tightening the handwheel or just to much push on the gouge.

David (Timberbits) M2 looks a good idea

You can also test a mandrel for bend in the lathe. Put it between centres and bring a pencil (on the tool rest) up to it. If the pencil line goes all the way around then it's straight. If the line only goes part way, then push it slightly in the direction away from the centre of the pencil line and try again until it's straight. As Wheelin' said also make sure you don't tighten up the nut or the tailstock too much either.

Peter

The dead cenre cannot make any difference, if you tailstock is not aligned properly.

Hi, I know what your are going through. I had the same problem. Now I just get the blanks within 1.5 mm on the mandrel and then go straight to the dead centre/live centre combo. I don't even use the bushes. I just nip them up so blanks are turning and take small cuts and sand down to size. I use digital calipers to get them the right size. Never had a problem since. There is a slight burr to remove from inside the brass before putting together but seems to work.
Kim

I've started to do as per shazzkim - seems to work

I also like the between centres for finishing

The dead centre live centre combination has been used by turners from the IAP for a number of years. Works for them.

Sounds like its worth a try

Just a couple of observations in this, I would rough close to size to leave a minimal cleanup between centres, you are essentially wedging the workpiece on 2 very small areas of brass to get enough friction to drive the workpiece, has to be tight enought to grip but not tight enough to distort the brass tube .If you consistantly get ovality in the turning on a mandrel,suspect your ends are not perfectly square to your tubes,this will force them off centre when you tighten on a mandrel ,hard to pickup when in the rough but after getting to round ,stop and loosen locking nut ,spin the blanks on the mandrel by hand you will see any runout easily, if it looks ok ,tighten nut and spin again with power if all is square there will be no difference ,if it looks a bit wobbly then something has altered either some wear in bushes to allow movement on the shaft,or ends not square to tubes and the pressure of the locknut will tend to force it to one side, giving you some degree of runout. I always loosen the locknut spin the workpieces and retighten just enough to grip for finishing , this relieves any end pressure stresses , I just find from my point of view that turning between centres slows me down ,and restricts working space on the blanks .Each of us finds a way to achieve the end goal hehe, Cheers ~ John

Are you using the Live centre (standard centres do not fit correctly) that came with your lathe or an aftermarket one that fits the hole correctly in the end of your mandrel.

If yes to the first question, get a 60° Live centre from McJings that fits your Mandrel, otherwise something is out of kilter on your lathe and you need to do a step by step process to find out why.

Dave this was my initial thread for a no mandrel set up back in 2007, but had been using it for a couple of years before that. https://www.woodworkforums.com/f69/no...-set-up-53900/ I have upgraded the dead centers, a machinist friend made them for me you can see them in this thread https://www.woodworkforums.com/f69/ne...centres-57700/ I hope this was a help to you.

darren

I only turn between centers and have for quite some time.
If your HS and TS are out of alignment, or your blanks aren't square it won't help anything.
There isn't a problem with crushing anything as it only takes enough pressure to keep it from spinning on the centers. The commercial bushings will work, however, there are many of them that aren't concentric and will create OOR also. I use custom made bushings that have the correct 60* taper to fit the centers.
For the slims and the like, it takes the custom bushings so it fits inside the tube.
This is the only way to turn, there is no flex and no nuts and spacers to deal with. It only takes a couple seconds to switch it out.

Thanks for the responses all. I didn't get any email updates though

I'm not using the original live centre - it was awful. I don't know what the angle of the new one I've got it, but I'll check.

I will play with a few of the ideas listed above and see how I go. Lots to think about.

Thanks again,
Dave

Originally Posted by Ozkaban

Thanks for the responses all. I didn't get any email updates though

I'm not using the original live centre - it was awful. I don't know what the angle of the new one I've got it, but I'll check.

I will play with a few of the ideas listed above and see how I go. Lots to think about.

Thanks again,
Dave

Dave

If you want to borrow my dead centre far a couple of weeks, let me know. I'm not getting much shed time at the moment