Thread: Safe drive / Ring drive centres

Hi Peter,

For decades I've been advocating the use of a dead center as the drive center for teaching skew chisel use. For some reason they are now popular as "safety drives."

Turners learning to use a skew should never be taught with the head stock end of a blank restrained in a scroll chuck.

The dead center needs to be seated into a reasonable pilot hole for very dense woods, however a simple centre mark is all that is required in softer woods. Mount the spindle blank as you normally would for "between centers" turning, replacing the spur drive center with the dead center and use a revolving center of choice in the tail stock.

Adjust the tail stock pressure so that it is firm enough to hold the blank securely but only sufficiently to drive the blank.

The dead center acts somewhat like a clutch, in the event of a catch the blank remains stationary i.e. "stalling", whilst the dead center spins in the blank.

I recommend that nervous beginners / intermediate turners start with an already round blank, a dowel around 25 to 30mm dia, and with minimal tailstock pressure so the blank spins with any skew contact. Then increase the pressure until you can just establish a cut, but with frequent "stalling".

As confidence builds, increase the pressure a little more, and step up to squarish blanks and "rough down" with the skew. Then advance to larger blanks etc. Eventually when the turner is confident with their skew chisel proficiency replace the dead center with a spur drive. Eventually moving on to a scroll chuck with tail stock support, then without support.

The simplicity and beauty of this process is that there are no horrendous catches in the initial stages that scare turners away from the skew.

I know SE QLD Woodworking Supplies stock them, but may not be on their website. I think Carroll's would have them. McJing's have a set with a hollow drive (ring) center which will perform the same task, though a little more fiddly to "center" on a blank.

4pc Drive / Live Centre Set (mcjing.com.au)

or if you have a collet chuck, any cone or ring center designed as a replaceable center in a "live center" can be used.
Live Centre 5 in 1 (vermec.com)

The best source of MT2 dead centers is suppliers to our metal turning colleagues.

Originally Posted by Mobyturns

Hi Peter,

For decades I've been advocating the use of a dead center as the drive center for teaching skew chisel use. For some reason they are now popular as "safety drives."

Turners learning to use a skew should never be taught with the head stock end of a blank restrained in a scroll chuck.

The dead center needs to be seated into a reasonable pilot hole for very dense woods, however a simple centre mark is all that is required in softer woods. Mount the spindle blank as you normally would for "between centers" turning, replacing the spur drive center with the dead center and use a revolving center of choice in the tail stock.

Adjust the tail stock pressure so that it is firm enough to hold the blank securely but only sufficiently to drive the blank.

The dead center acts somewhat like a clutch, in the event of a catch the blank remains stationary i.e. "stalling", whilst the dead center spins in the blank.

I recommend that nervous beginners / intermediate turners start with an already round blank, a dowel around 25 to 30mm dia, and with minimal tailstock pressure so the blank spins with any skew contact. Then increase the pressure until you can just establish a cut, but with frequent "stalling".

As confidence builds, increase the pressure a little more, and step up to squarish blanks and "rough down" with the skew. Then advance to larger blanks etc. Eventually when the turner is confident with their skew chisel proficiency replace the dead center with a spur drive. Eventually moving on to a scroll chuck with tail stock support, then without support.

The simplicity and beauty of this process is that there are no horrendous catches in the initial stages that scare turners away from the skew.

I know SE QLD Woodworking Supplies stock them, but may not be on their website. I think Carroll's would have them. McJing's have a set with a hollow drive (ring) center which will perform the same task, though a little more fiddly to "center" on a blank.

4pc Drive / Live Centre Set (mcjing.com.au)

or if you have a collet chuck, any cone or ring center designed as a replaceable center in a "live center" can be used.
Live Centre 5 in 1 (vermec.com)

The best source of MT2 dead centers is suppliers to our metal turning colleagues.

Perhaps not the way I learnt. it was via a chuck and a death or glory sort of journey . But I agree, its as fail safe as you can ever get on a lathe and it will teach about light touches and their value.

Originally Posted by hughie

Perhaps not the way I learnt. it was via a chuck and a death or glory sort of journey . But I agree, its as fail safe as you can ever get on a lathe and it will teach about light touches and their value.

Sadly, new turners using a skew are typically doomed to the "non-glory" path. The most difficult part of getting gun shy turners, those who have had a bad experience with a "skew moment," is gaining their trust to give it another go using the above technique.

I've had several very nervous turners take it up after some convincing and have had them confidently practicing using a skew within minutes. Taking the fear factor out of the equation makes a huge difference. One at a Proserpine Turnout was then showing others her new-found skills on day two. Very pleasing to see the "fear factor" gone!

Far easier to start off with a much higher chance of achieving "glory."

Thanks @Mobyturns!

This was exactly my thinking, as someone who has a balance condition that can make me wobbly, safety is front of mind until i get my positioning and movements figured out. I need something forgiving till I get there.

I think my confusion was focusing on old style dead centre's only, and looking at your recommendations I see 'Steb Centres' being described in the same way, with the spring loaded point offsetting the crown of teeth.

For example Woodworking Supplies S/E QLD - 1

This seems to do what I need I think. Thanks again for the advice!

Peter

Steb centers definitely do not perform the same role.

I can see how this is going to confuse lots of people then! For example, the text here seems to describe exactly the behaviour for the wood as you suggest:

CWS Store - Robert Sorby Steb Centre

However logically what you say makes sense, any teeth even if lightly engaged will transmit more torque than a friction ring.

Luckily I found one on McJing, here is a link for anyone having the same search trouble as I did!

Just a moment...

Thanks again for the advice!

Pete

Is this the sort of thing your after Peter?

Untitledpoiuy.jpg

4PCS Carbide MT1 MT2 Live Dead Center Morse Taper Lathe Chuck CNC Cutter Tool AU | eBay

Hi

yeah i saw that set but it doesnt have a centre point making it tough to align. Also I worry that if you want it to just drive there is not much holding it.

The McJing one i linked above has them but no stock till Feb... so I will probably wait till then.

Peter

So just to close out, because the safety center isnt available till Feb i did some testing today with the steb centre.

Whilst it is touchy to control, it does exactly what I wanted. Loosen the quill, and it stalls at a touch, tighten it up to get more drive. Catches were minor and I could learn pretty safely. Turns on the quill of 1/8 rotation at a time gave decent control steps.

The only thing I found is that it cuts a grove as it first settles in, so you lose drive progressively and need to tighten it a bit but then it settles nicely. As I normally stop at first to check tightness this isnt a big deal for me.

This was on pine though, not sure how a hardwood will go but if its like this I may not bother with the safety centre. For an outright beginner I would still recommend the safety but if you have some past experience (long past in my case) and are used to handling tools in a safe and careful way, then it does the job.