stuck drive centre

[NickWelford]

You could of course use a drive spur that fits in the chuck, therefore not needing to use the morse taper anyway.

 

[Random Orbital Bob]

That's what I use now and its absolutely brilliant. I now rarely need to take my chuck off, except to change to a different chuck. In fact you may recall I alerted the forum to the XT700 Rutlands Easter offer and a few folks bought one. Well I was one of them, I also bought the SN2 Cole jaws (not from Rutlands) for reverse turning the feet on bowls mostly. I've now installed the Cole Jaws as a permanent fixture in my new xt700 so I can avoid the jaw change faff. I've used it twice already and what a difference it makes. Before I was using a 12" circle of MDF and then bringing the tailstock up to support the bowl. There was no clamping except the squeeze pressure offered by the tailstock. Didn't matter what I did, I could not get the bowl dead centred so that method sucked. With the cole jaws actually clamping the bowl in reverse its a much more positive holding solution and I can now confidently shape the bottoms at a sensible speed. I'm getting finishes on the bottoms of work I could never achieve before

 

[Spindle]

Hi

I find the chuck gets in the way when turning small spindles - I'll stick with Stebcentres in the taper.

As regards additional chucks rather than jaw changing, it's a slippery slope, I'm currently on seven and looking for number eight.

Regards Mick

 

[Woodmonkey]

Wow 7 chucks! And there's me thinking 2 was extravagant! I didn't hit it into the taper at all, it was only the force of the tailstock that pushed it in there.

 

[Spindle]

I didn't hit it into the taper at all, it was only the force of the tailstock that pushed it in there

Hi

When you advance the tailstock you should only use sufficient pressure to locate the work, just tighten the wheel until the sideways play disappears. Check tightness every now and again whilst you work but don't be tempted to over tighten, in thin spindles it will result in them bowing under the pressure and inducing vibration.

Regards Mick

 

[Random Orbital Bob]

I like the idea of a stebcentre but haven't yet tried one. There must be a make of stebcentre that fits into a Supernova 2 surely?

I'm also like you Woody, my spur drive can get wedged with only pressure from tightening the tailstock into the wood. I haven't managed to get it properly stuck mind.

 

[Spindle]

There must be a make of stebcentre that fits into a Supernova 2

Hi

Yes there is:

http://www.turners-retreat.co.uk/machin ... teb-chucks

Good for most things but the pressure to 'engage' the prongs can be enough to bow small diameter work - I use a ring centre in that case.

Regards Mick

 

[Random Orbital Bob]

I didn't hit it into the taper at all, it was only the force of the tailstock that pushed it in there

Hi

When you advance the tailstock you should only use sufficient pressure to locate the work, just tighten the wheel until the sideways play disappears. Check tightness every now and again whilst you work but don't be tempted to over tighten, in thin spindles it will result in them bowing under the pressure and inducing vibration.

Regards Mick

If I do that I find my spur drive starts to spin in the headstock and stalls the wood. This often happens even if I've rubber malleted it in to engage the spurs and not just the central cone. So to overcome that I end up winding the tailstock in harder to repinch the spurs. I never do that on thin spindles for the bowing reason you mention but take lighter cuts on thin spindles anyway. That's one of the reasons I like the idea of a stebcentre because they grip the tailstock end better apparently.

 

[Random Orbital Bob]

we crossed in the post Mick

 

[Spindle]

Hi Bob

I think you need to try a different drive centre - the tapers should seat much more easily than you describe.

I've never used a Stebcentre in the tailstock - sometimes a ring centre if I'm worried about splitting the work.

Regards Mick

 

[Random Orbital Bob]

I've got two now, one is a record one that I bought with the lathe 18 months ago. That's a 4 prong drive. The newer one is the chuck compatible version. Its design is different, 4 prongs again but they're like little half moons at each corner. The morse taper original is definitely better at holding the work but of course less convenient than the chuck version.

Don't get me wrong, it's not a biggy, just a bit inconvenient every now and then.

Do you think the Supernova 2 chuck version of the steb centre would grip the work better?

 

[Spindle]

Hi

Apart from the minor niggle I referred to earlier I can't fault Stebcentres, (well it would be nice if they were a little cheaper :roll: ), They are my 'go to' centres. I have the 1/2" and 7/8" versions, the 1/2" gets used for all but the largest work. 3" oak spindles roughed down from square using the 7/8" with no problem.

The other major plus for me is that I can remove and remount work without stopping the lathe - ideal when I'm fettling spigots to fit tenons.

Regards Mick

 

[Grahamshed]

I have the steb centre that fits in a chuck ( I imagine it would fit pretty much any chuck ) and it is very easy and convenient to use but I have not seen a 1/2 inch version.

 

[Woodmonkey]

Yep same as bob, if I don't crack up the tailstock then inevitably the drive centre loses grip and just starts to spin on the wood. Maybe a new one is in order. Haven't come across steb centres before will have to look into it.

 

[Grahamshed]

A steb centre would only work with the tail stock pushing at the other end

 

[Random Orbital Bob]

Yeah I get that Gray. But from Mick's comments and just by generally looking at them they have a more aggressive (grippy) tooth pattern. They seem to have many small teeth rather than fewer big ones like traditional spur drives so I can see how they would grab the work better.

And Mick, just by chance it was 3" square oak spindles I was turning today (bed feet raisers for my sister) when my chuck prong centre started slipping and that was after malleting it in before I started turning. They were really heavy and chunky mind, perhaps they were just too large for that size of spur centre?? Like I say, I did them in the end but wound in the tailstock a couple of times. There was no danger of bowing of course due to their sheer mass.

 

[Spindle]

Hi

When using a four pronged centre on large work it helps to cut a couple of registers using a bandsaw and then locating the drive centre in the cuts.

Also a rubber mallet is not my tool of choice - I use one of these:

http://www.thorhammer.com/Hammers/Plastic/

Regards Mick

 

[Random Orbital Bob]

That thing you linked....that's exactly what I use...just named it incorrectly because it has one side rubber and the other side a hard plastic. I also use a wooden mallet, whichever is nearer.

 

[Grahamshed]

 

[Robbo3]

I had the same problem with the APTC 1628 lathe & I couldn't believe how much force I had to use to knock the drive out of the morse taper. I started with a plastic faced mallet, progressed to a 20 oz claw hammer & ended with a 2 1/2lb lump hammer. Even then I had to pull the lathe away from the wall to get enough swing - that shows the amount of force I was using.

I thought that the composite ball on the end of the knock-out bar might not have liked all the attention but it came through it as if nothing had happened.

Although I had originally cleaned the lathe & centres with a paraffin soaked rag perhaps I didn't do it thoroughly enough. Cleaned the internal taper & the centre with a clean piece of rag & haven't had a problem since although the centre now has a flattened nose where I failed to catch it.