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Tiger
13th March 2009, 02:32 PM
It has always bugged me how on my lathe the drive centre at the headstock end fails when I use softwood and just cuts a groove rather than holding the wood securely. This happens almost as soon as I apply the tool to cut and sometimes on cuts that aren't that heavy. I have to keep filing the spurs on the drive centre or really tighten the tailstock to hold the rotating piece. Some hardwoods don't fare much better as the spurs don't penetrate the workpiece enough. Are the steb centres designed to get around this problem? Had enough and will buy one if it helps. I upgraded the drive centre that came with the lathe and even that needs constant filing and attention and only does a mediocre job.

orraloon
13th March 2009, 02:49 PM
Tiger,
I hope you don't take this as a silly question but are you sawing a cross (X) for the spurs to locate in. Also take the drive out of the lathe and bang it into the wood with a rubber or wood mallet.
Regards
John

Tiger
13th March 2009, 02:53 PM
G'day John, I do all that you suggest yet the workpiece still rotates at times especially with heavy cuts. I turn a lot of pine and it is particularly noticeable then.

RETIRED
13th March 2009, 02:55 PM
You should never have to do either of those things.

The Steb centres are fantastic IMHO.

I have always said that the best improvement to a lathe is get decent drive and tailstock centres.

Tiger, it could also be technique or blunt tools that is causing the problem.

orraloon
13th March 2009, 03:10 PM
Tiger,
I reckon you need a new center then.


,
I have never had a Steb center but I will keep it in mind for the future.
I have 2 drive centers and no idea who made either of them. One works well while the other can slip sometimes so some are better than others.
Regards
John

Texian
13th March 2009, 03:10 PM
Another vote for technique and/or tools as source of problem.

RETIRED
13th March 2009, 03:36 PM
Tiger,
I reckon you need a new center then.


,
I have never had a Steb center but I will keep it in mind for the future.
I have 2 drive centers and no idea who made either of them. One works well while the other can slip sometimes so some are better than others.
Regards
JohnI agree totally. Had the same myself.

RETIRED
13th March 2009, 03:37 PM
Tiger. If you want to bring the centres and your chisels down here I will have a look.

TTIT
13th March 2009, 04:03 PM
Tiger. If you want to bring the centres and your chisels down here I will have a look.I might have to come too !!! Damned if I can get those Steb centres to hold any better than a normal spur-drive :B:B

Tiger
13th March 2009, 04:36 PM
Hi , not technique nor sharpness, never have a problem when work is supported in chuck or other methods of holding.

issatree
13th March 2009, 04:58 PM
Hi Tiger,
I've been turning for 28 yrs, & I had that problem as well. What says is most likely true, but they still bore a hole in the softer timbers.
My Idea is you find a MT 2 older type drill, cut the drill part off, so as you have a nice round piece of steel. Clean the taper, whack it back up the head stock.
With a small Skewchigouge, turn the end, & make a ring & cone end, most like you tail stock.
There will be a HOWL about turning steel in your lathe, but I have made a heap of the Centres. I can honestly say I have never had a problem with either making them or using them .
The thing about is that your wood may never come out of the lathe, but will drive most every wood you can think of. The only other thing is if it doss slip, you just slightly tighten your tail stock, so in practice, all your wood will do is spin on the
Ring & Cone. When turning the steel, of course make sure that your tool rest is approx. 1-2 mm away, with no over hang, Speed, well that is up to you, my guess would be around 1000 revs.or less if you want. I have used the Centre for about 7 years. never had a problem, but those cross drives, in my opinion are dangerous. If I knew how to send photos I would do it. REGARDS, ISSATREE.

new_guy90
13th March 2009, 05:42 PM
Hi Tiger,
I've been turning for 28 yrs, & I had that problem as well. What says is most likely true, but they still bore a hole in the softer timbers.
My Idea is you find a MT 2 older type drill, cut the drill part off, so as you have a nice round piece of steel. Clean the taper, whack it back up the head stock.
With a small Skewchigouge, turn the end, & make a ring & cone end, most like you tail stock.
There will be a HOWL about turning steel in your lathe, but I have made a heap of the Centres. I can honestly say I have never had a problem with either making them or using them .
The thing about is that your wood may never come out of the lathe, but will drive most every wood you can think of. The only other thing is if it doss slip, you just slightly tighten your tail stock, so in practice, all your wood will do is spin on the
Ring & Cone. When turning the steel, of course make sure that your tool rest is approx. 1-2 mm away, with no over hang, Speed, well that is up to you, my guess would be around 1000 revs.or less if you want. I have used the Centre for about 7 years. never had a problem, but those cross drives, in my opinion are dangerous. If I knew how to send photos I would do it. REGARDS, ISSATREE.

ok first off that sounds so dangerous wood lathes are not meant to turn metal so that must have been a big strain to do, and holding the tool must have hurt! as for the drill your trying to turn HSS with HSS? properly made centers are hardened and ground expensive if you want to get some one to do that but why not use a dremal rotary tool or a die grinder secured to a sort of make shift tool post that should do it.

as for me i use the cheap drive center that came with my lathe and it must be over 16 years old but i have never had a problem with it even when the spurs are not in the wood and its just the center spike then again i put heaps of pressure on the tailstock to. one thought you guys haven't touched on is the angle of the grind on the spurs and the center spike, if it was a steep, sharp angle then it would go deeper into the wood easier and there would be less chance of it stopping to bore a hole. just a thought i did like the idea of making your own center .......ill post a link latter to sow you guys something

Patrick

Edit: this guy makes great stuff his web site is fuul of little things. i want to make one of these centers one day i think it will be a hell of a lot better than most on the market
http://www.frets.com/HomeShopTech/Projects/DriveCenter/drivecenter.html

RETIRED
13th March 2009, 05:43 PM
I might have to come too !!! Damned if I can get those Steb centres to hold any better than a normal spur-drive :B:BOccasionally I will get a slip if I catch or don't bring the tail stock up tight but in the main they are the best drives I have used except the 6" one on my "little" lathe. It don't slip.:D

Issa, that is called a dead ring centre and can be bought if people are reticent about turning steel.

They rely solely on friction to drive but in production work they are very handy as the timber stops for removal.

issatree
13th March 2009, 07:44 PM
To Patrick, Tiger & ,
I had better clarify what I was explaning. In reality I have only made 1 of the ones I explained. I thought it would be easier for Tiger to find a No. 2 MT Drill, as most of the sunday Markets may have them or a Swap Mett, most certainly, and I failed to say that they had to be heated and then let cool before attempting to turn the steel.
I actually used ABORS from Jacob's Chucks, as I have a nice supply now, & they are not HHS, well, these are not anyway. I have a friend who has a Metal Lathe & he can do the hard ones.
I really don't have that problem turning the steel in my "Tough Lathe", & there is no pressure whatsoever on the tool or the lathe or the steel. You don't drive the tool into the steel that hard as to cause pressure. In fact you can manage a beautiful long shaving if you do it right .
I'm certainly not out to get anybody hurt, but I suppose there are Turners & there are Turners. This was just an inexpensive way of making a Drive Dog. I will never use a Star Drive again as long as my tail points to the ground.
I hope this explains the way I do things.
REGARDS,
ISSATREE.

NCPaladin
14th March 2009, 05:11 AM
I had trouble also with the drive center burying itself in soft or wet wood. I purchased a two prong drive center (see pic if I can post it). The prongs on mine are about 1 inch long and that solved that problem. If you drive it in deep, it can not spin in the wood and loosen up. If you get one make sure it has the setscrew to adjust how much you want the center pin to extend. I also have steb centers for hard wood. And they are terrific. I rarely use my four prong drive any more (I probably would if I did more spindle work,
Mike

rsser
14th March 2009, 05:41 AM
Yeah, I have a couple like that.

Tiger hasn't said whether he's spindle or 'faceplate' turning.

A 1" drive dog with a big lump can give you slipping.

A homemade alternative is to use a small faceplate, drill 3 holes evenly spaced around it, fix protruding bolts through them and grind the ends to points.

For natural edge bowls a large screw-on drive dog is the go (see eg. the Vermec website).

RETIRED
14th March 2009, 07:37 AM
Oops. I assumed that Tiger was doing "real" turning and forgot that he could be doing the other.:-

Oddjob1
14th March 2009, 07:47 AM
I have been turning for over 40 years and only use a four pronged spur, I have taken square to round with it with no trouble, maximum dia between centres I've turned is 300mm or so! The only thing to make sure of is to hammer that drive centre in very well, with a wooden mallet of course, then when you get it set up and are winding in the tailstock, give the work another couple of whacks to be sure.

Hope this helps....Jeff

Tiger
14th March 2009, 08:32 AM
Ern, to clarify I'm talking about spindle turning, mostly 1 inch in diameter, around 6 to 7 inches long. I use faceplates for most other things because of the problems with the drive centre. From what I can tell, the steb centre will help with hard woods but may not be much better for the softer woods, I was looking at the Carbatec one which sells for around $40 but there may be a quality issue as well to consider.

rsser
14th March 2009, 09:01 AM
Oops. I assumed that Tiger was doing "real" turning and forgot that he could be doing the other.:-

You mean unreal turning ;-}

Seems not anyway.

How far are your spurs going in Tiger?

Are the tips sharp? If not, take to them with a file.

Are the workpiece ends square to their axis, so that all four spurs are engaging?

FWIW, if there's enough length/diam in the piece, you could also just true one end, cut a shoulder and whack it in a chuck.

... k, run out of ideas now.

oldiephred
14th March 2009, 09:13 AM
Sometimes this slip problem can be caused as a result of the drive center and the tailstock centers not being lined up or the work piece is not parallel to the drive and tail centers. As a result of misalignment there are only one or two "dogs" actually driving raher than all four so they quickly work loose, especially in soft wood.
Anyway, best of luck with that problem.

new_guy90
14th March 2009, 11:22 AM
To Patrick, Tiger & ,
I had better clarify what I was explaning. In reality I have only made 1 of the ones I explained. I thought it would be easier for Tiger to find a No. 2 MT Drill, as most of the sunday Markets may have them or a Swap Mett, most certainly, and I failed to say that they had to be heated and then let cool before attempting to turn the steel.
I actually used ABORS from Jacob's Chucks, as I have a nice supply now, & they are not HHS, well, these are not anyway. I have a friend who has a Metal Lathe & he can do the hard ones.
I really don't have that problem turning the steel in my "Tough Lathe", & there is no pressure whatsoever on the tool or the lathe or the steel. You don't drive the tool into the steel that hard as to cause pressure. In fact you can manage a beautiful long shaving if you do it right .
I'm certainly not out to get anybody hurt, but I suppose there are Turners & there are Turners. This was just an inexpensive way of making a Drive Dog. I will never use a Star Drive again as long as my tail points to the ground.
I hope this explains the way I do things.
REGARDS,
ISSATREE.

theres more than one way to skin a cat, its good to know that a wood lathe will turn soft metals easily and done safely. well we all put in our 2 cents and a dead cup center (thats the picture i got) would be very handy to have.

to be honest i haven't really had a problem with any drive center like what you guys are describing but i would think that if its pushed in the wood far enough and pressure from the tail stock is kept high, then the wood would never slip or twist out of the centers to cause problems regardless if it was a soft or hard wood. i still think that if your having problems then go for a different center made for the wood your turning. did anyone follow the link i posted what do you guys think?

Patrick

RETIRED
14th March 2009, 11:40 AM
New Guy. Yep, Had a look.

Tiger, one other thought, what brand of lathe?

Jim Carroll
14th March 2009, 12:02 PM
If you are only turning 1" diameter then a 16mm drive spur will do the job real easy.

Tiger
14th March 2009, 10:19 PM
it's the basic MC900 lathe, made in China, cheap. Today I filed the spurs and it helped, though a couple of hours of turning later, the work started slipping again.

RETIRED
15th March 2009, 07:49 AM
Check that you are not getting "creep" in your tailstock while you are working.

Calm
15th March 2009, 08:19 AM
What speed are you running the lathe at?

Does the centre in the tailstock have a bearing in it or is it fixed?

As says is the tailstock "slacking" off on you?

Cheers

Tiger
15th March 2009, 08:23 AM
and David,

Speeds vary but generally around the 1200 rpm mark. I am using a live centre in the tailstock. If there is creep that should be fixable by tightening the camlock nut but I'm not sure that there is any creep.

Calm
15th March 2009, 08:42 AM
and David,

Speeds vary but generally around the 1200 rpm mark. I am using a live centre in the tailstock. If there is creep that should be fixable by tightening the camlock nut but I'm not sure that there is any creep.

I would suggest spinning 1 inch diameter as fast as possible - also everytime the centre "slips" a bit tighten the tailstock to take up the slack -

I fing my lathe "chews" out the end of pine & cypress as well but put it down to being soft wood.

Hope that helps

Cheers

brendan stemp
15th March 2009, 10:45 AM
I would also like to put my support behind the Steb centre. Fantastic things. Only problem is that I think they are inordinately expensive... Mr Steb must be getting big royalties from Sorby!

Having said that I would also suggest holding spindles in a chuck using pin or shark jaws. I do this all the time and I can guarantee 100% no slippage!

Robomanic
15th March 2009, 03:52 PM
Something that I have transfered from early fitting and turning days was to wind the tailstock up but not lock the spindle. The handwheels have quite a heavy handle on them that makes it unbalanced. Winding it up so that the handle is on the far side gives it enough torque to keep the spindle tight against the workpiece. If there is any vibration or bedding in, the spindle automatically beds in further. You just need to keep an eye on it so if the hand wheel makes it to the bottom you can re-adjust and keep going. Don't know about your lathe but that might help.

Tiger
22nd March 2009, 03:38 AM
Thanks to those that helped here. I find that tailstock creep can be decreased if I tighten the camlock nut under the tailstock. It's a little awkward to get to and is quite a decent size nut but usually it can be tightened with finger pressure. It does come loose too easily for my liking though.

Skew ChiDAMN!!
22nd March 2009, 03:49 AM
Yeah, those nylock nuts seem to wear (ie. become loose) just from the vibration.

Mine got so bad that I needed to tighten 'em almost every time I moved the banjo or tailstock, so I cut 'em each into two smaller nuts with a hack-saw, so after getting the tension right I could snug up the second half as a lock-nut.

That way I could still slide the tailstock or banjo off the end. (Wish they'd make that cut-out just a wee tad deeper...)

Edit: or did I replace the original nuts with nyloks way back when? And then found out they weren't the best choice? My memories a bit hazy on that. :-

rsser
22nd March 2009, 06:12 AM
Or get the tension right and use a locking compound?

AUSSIE
22nd March 2009, 06:39 AM
Would a soak with thin CA harden wood enough .I am not a wood turner.But just use a lot of CA.It toughens up pine for my purposes
Aussie

Calm
22nd March 2009, 09:00 AM
Yeah, those nylock nuts seem to wear (ie. become loose) just from the vibration.

Mine got so bad that I needed to tighten 'em almost every time I moved the banjo or tailstock, so I cut 'em each into two smaller nuts with a hack-saw, so after getting the tension right I could snug up the second half as a lock-nut.

That way I could still slide the tailstock or banjo off the end. (Wish they'd make that cut-out just a wee tad deeper...)

Edit: or did I replace the original nuts with nyloks way back when? And then found out they weren't the best choice? My memories a bit hazy on that. :-

A way to rejuvenate Nylock nuts is take them off sit them on something solid, lay a screwdriver (something round) across the nylock and hit it with a hammer - the little dents it puts is squashes the plastic bit out again giving the thread a fresh bite.

Cheers

Woodwould
22nd March 2009, 09:07 AM
I'll second semi-permanent thread-locking compound.

A better solution to Nylock nuts are K-nuts (all-metal locking nuts that don't lose their grip).

Tim the Timber Turner
23rd March 2009, 06:15 PM
I"ll put my vote in for the Steb centre.

I had a couple of the first ones made by Gerry Stebbings. before he sold the design to Sorby.
They are safer to use with kids and learners, they also make less noise if you should try and reshape them with a skew (ouch):no:.
Can also act like a clutch and can provide some slippage in the event of a catch.

I use the standard one (22mm) for diameters up to 50mm..

For larger diameters up to 100mm I like the big Sorby version (32mm). This is a great bit of gear.

I have found the Carba-Tec version better than than the original Steb Center.
The steel is better quality and harder wearing. I don't know about the current Sorby version.

Another option is the Vicmarc drive dog punch. one hefty wack with a 4lb hammer and no problems for ever more with a slipping four prong drive centre.

Cheers

Skew ChiDAMN!!
23rd March 2009, 06:32 PM
Tiger, just as a matter of idle curiosity... what sort of blank weights/diameter are you mainly having problems with?

If you're turning heavy blanks or small branches/logs (say anything around 8"+ in diameter) then an ordinary spur centre is pretty much a bad choice. The inertia of the log at start-up will tend to make the spurs slip, and once started, any leverage on a tool handle will just make the slippage worse.

A better alternative is to use a small, 2"(ish) faceplate and permanently fit it with good steel nuts'n'bolts. Cut the ends of the bolts short, maybe only 1/4" projecting past the nuts, then sharpen them to points. A super-centre.

Guaranteed positive traction... :2tsup: (Mind you, if you do get any slippage with one of those, it will probably make a nice little mortise so you can use your chuck in expansion mode... :innocent:)

RETIRED
23rd March 2009, 06:56 PM
I"ll put my vote in for the Steb centre.

I had a couple of the first ones made by Gerry Stebbings. before he sold the design to Sorby.
They are safer to use with kids and learners, they also make less noise if you should try and reshape them with a skew (ouch):no:.
Can also act like a clutch and can provide some slippage in the event of a catch.

I use the standard one (22mm) for diameters up to 50mm..

For larger diameters up to 100mm I like the big Sorby version (32mm). This is a great bit of gear.

I have found the Carba-Tec version better than than the original Steb Center.
The steel is better quality and harder wearing. I don't know about the current Sorby version.

Another option is the Vicmarc drive dog punch. one hefty wack with a 4lb hammer and no problems for ever more with a slipping four prong drive centre.

Cheers:2tsup:


Tiger, just as a matter of idle curiosity... what sort of blank weights/diameter are you mainly having problems with?

If you're turning heavy blanks or small branches/logs (say anything around 8"+ in diameter) then an ordinary spur centre is pretty much a bad choice. The inertia of the log at start-up will tend to make the spurs slip, and once started, any leverage on a tool handle will just make the slippage worse.

A better alternative is to use a small, 2"(ish) faceplate and permanently fit it with good steel nuts'n'bolts. Cut the ends of the bolts short, maybe only 1/4" projecting past the nuts, then sharpen them to points. A super-centre.

Guaranteed positive traction... :2tsup: (Mind you, if you do get any slippage with one of those, it will probably make a nice little mortise so you can use your chuck in expansion mode... :innocent:)You mean like these? These are the drives off the big mongrel.

Tiger
23rd March 2009, 09:00 PM
Skew, just talking about spindle turning with approx 300 mm long, 50 mm wide. The sort of stuff you wouldn't expect to have any problem with.

Woodwould
23rd March 2009, 10:41 PM
Another option is the Vicmarc drive dog punch. one hefty wack with a 4lb hammer and no problems for ever more with a slipping four prong drive centre.

I use a copper-faced mallet to belt the drive centre into turning stock; it doesn't damage the drive centre's end.

Skew ChiDAMN!!
24th March 2009, 01:37 AM
:2tsup:

You mean like these? These are the drives off the big mongrel.

Not many of us can say they have their own tunnel-boring machines... :D

Grumpy John
24th March 2009, 10:23 AM
A while back, in another life when I had access to as many lathes, milling machines, grinders and welders as I could wish for :C I made a small (90mm dia.) faceplate. In an unusual (for me) moment of foresight I tapped the 6 screw holes. Since then I have modified some high tensile grub screws to include a 60 deg. point. I now have a drive plate as well as a face plate :). Anyone with access to metal cutting taps should be able to modify their existing faceplate/s to accommodate some pointed screws. The screws do not have machined on a lathe, hand sharpening on a grinder is sufficient. I do recommend obtaining high tensile screws though. My only regret is that I didn't drill and tap the centre to accommodate a woodscrew so that I could use it as a screw chuck.

Woodwould
24th March 2009, 10:51 AM
Nice job GJ. :2tsup:


My only regret is that I didn't drill and tap the centre to accommodate a woodscrew so that I could use it as a screw chuck.

If you did have a central woodscrew, you could wind it into the stock first and then tighten the dog screws in for the ultimate traction.

Grumpy John
24th March 2009, 10:54 AM
Nice job GJ. :2tsup:



If you did have a central woodscrew, you could wind it into the stock first and then tighten the dog screws in for the ultimate traction.

Exactly what I was thinking WW, I still have mates (yes David, I do have mates :p) in the trade so all is not lost.

Tim the Timber Turner
24th March 2009, 11:05 AM
Rather than points I find 3 spade bit tips, like a screwdriver blade, works better in green timber and bark. In soft wet timber, round points tend to slip and spin

A drop of locktite will stop the 3 blade tips rotating.

A round centre point which is adjustable for length is also a help when turning burls.

The point is set slightly longer than the 3 driving tips, this makes it easy line up the mark and to make small adjustments to the position of the burl.

I modified a Vermec Chuck Drive Dog with longer and bigger diameter grub screws.

I must learn how to post photos and links it would save a lot of typing.

Yes I know it's probably not hard but!!!

cheers:)

RETIRED
24th March 2009, 12:18 PM
The 2 pictured have chisel points.

And Tim, it's easy. Even I can do it.:wink: