AWGB Woodturning Forum
General Category => Tool tips & reviews => Topic started by: MCB on July 26, 2015, 01:02:26 PM
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I've noticed that when I'm roughing down a square section spindle blank, sometimes the blank catches and stops rotating, even though I had tried to secure it onto the drive centre (by tapping with a mallet)
I wonder if this suggests that the drive centre isn't inserted enough into the blank because it's blunt.
Is it possible to sharpen the centre or do I need to replace it.
If the former, how does one sharpen it.
With best wishes and thanks.
MC
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This happens sometime in softer woods and personally I have got a habit of just giving the tailsock a tweak every now and then. If you do want to sharpen the centre give it a wipe over each face with a file. Wouldn't advise trying it on the grindstone. Might be other options from someone else
pete
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chuck the 4 prong away and get a stebcentre, i've caught mine once or twice and it's got a bit smoother by being touched with sandpaper every so often and it still grips spectacularly well...
well worth the money in my opinion...
mine's chuck mounted but i also have the morse taper ones if i want to do lots of spindle turning and won't need a chuck.
pete is right about the occasional winding in of the tailstock, works a treat...
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I agree. Get a Steb centre. Well worth the money. Two types available. One with a Morse taper and one to fir a four jaw chuck. Malcolm.
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Another one for the steb centre and occasional tweak.
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I agree. Get a Steb centre. Well worth the money. Two types available. One with a Morse taper and one to fir a four jaw chuck. Malcolm.
Gentlemen
Thank you for taking the time to respond.
Is it worth getting the Steb centre for the Tailstock too?
What's the diameter of the BODY of the Steb that fits into a four jaw chuck? I need to check if it would fit in my Viper3
Very many thanks again
MC
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Any drive centre that fits into a chuck MUST have a parallel body as opposed to the morse taper or it just slides out. Sometimes called parallel drive centre
Pete
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If I were you and you are buying a Steb centre I would get a Morse taper one to fit your lathe the chances are that your chuck will grip it anyway.
No you do not need one for the tail centre.
Regards George
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Any drive centre that fits into a chuck MUST have a parallel body as opposed to the morse taper or it just slides out. Sometimes called parallel drive centre
Pete
I use a MT Steb center and it holds OK it cannot come out because the wood is holding it in. Wake up Pete ::)
Regards George
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Wide awake George LOL. I agree that should happen but I have had occasions where it has somehow worked loose as the chucks grip on the taper wasn't enough and it has started revolving loosely.Okay i phrased it badly. Just something that I have experienced so am wary of.
Pete
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Fair enough.
Just looked at one of mine and it has a flat area after the taper and that is where I grip it
Regards George
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The one I use in a chuck has a flat section just behind the head. Same on my jacobs chuck. Both I have used in a chuck.
Pete
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here is a picture of my 7/8th" chuck stebcentre and the measurements are thus.
length, 50mm
steb diameter (the teeth) 7/8"
main body's widest diameter, 30mm
rear diameter, 1"
narrow waist, 3/4"
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Gentlemen (I think everybody who responded can be so classified)
You have convinced me to buy a Steb Centre (or possibly two - one to fit in my Chuck)
Is anybody aware of any suppliers that sell them at below the usual price?
With best wishes and thanks again.
MC
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If I were you I would make sure it is a Step centre I bought a copy and it is just not the same.
Regards George
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With each rotation of a square blank there are four intermittent cuts, each one causing stress on the wood fibers that meet the drive center, as a .The result is loosening of the drive. In relation to the Steb Center, on seasoned stock I have found it to be good but on unseasoned wood (very fresh/just felled) I found that the fibers are too wet and flexible for the Steb center to hold due to the relatively small depth of grip resulting in slip. For this reason I have never personally purchased one as I found for the price a good four prong is all that is needed for both seasoned and freshly felled wood.
I would sharpen your four prong with a small diamond cone bit in a dremel type tool and spend the £50 + on an enjoyable day out with the family. For me it is just another gimmick, give a good our prong a good whack with a mallet and it is more than good enough for all needs.
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I also support the use of Steb centres...
... but there are times when my 4 prong or 2 prong drives still win out. I'd not do without them in my equipment range.
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I like mine but as Mark says they are an unnecessary luxury.
Regards George
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MC although I own a selection of steb centres I still use a 4 prong drive. I sharpen mine by touching them on the grind stone lightly and have done for years. Maybe you should just make a wooden mallet and hit it harder thereby driving it a bit deeper and helping it grip better. Just be aware that woodturning accessory manufacturers are very good at convincing woodturners that they need more equipment when normally all the turner needs is an increase in experience.
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MC although I own a selection of steb centres I still use a 4 prong drive. I sharpen mine by touching them on the grind stone lightly and have done for years. Maybe you should just make a wooden mallet and hit it harder thereby driving it a bit deeper and helping it grip better. Just be aware that woodturning accessory manufacturers are very good at convincing woodturners that they need more equipment when normally all the turner needs is an increase in experience.
Thank you
I don't need to make a mallet since I have a 2.5 lb engineer's hammer (that belonged to my late father) which should sink the four prong drive into the end of the spindle sufficiently far to do the trick if my copper hammer doesn't.
MC
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I use a 4 prong drive center and use the following method.
Insert the wood between centers then using the tails stock like a vice I then lock the head stock and rock the spindle back and forth until I can tighten the tail stock some more, repeat this a couple of times until you can no longer move the piece on the drive. this ensures any play or give in the timber is taken out and negates the fibers softening or working loose.
Obviously ensure your lathe has the strength to use the tail stock in this way.
I have rarely had to retighten during turning with this method. Don't forget to remove the spindle lock when completed. :o
Or if you have an unruly or odd shaped piece drill a hole with a forstner bit to sit the drive center into, then repeat the above.
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Some of the wood that I use Lazarus is either very soft or has splits and cracks so i need to be careful having it too tight or I would just break the piece up. In decent wood what you do sounds a sensible idea though. With the softer wood, I usually just use the centre to hold the piece long enough tpo make a tenone and then, if it is really soft, soak the tenon in thin CA glue to harden it up. If you think there is usually a way to turn most woods as long as it is safe .
Pete
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Also using the Tailstock as a vice could damage the bearings. I use a heavy mallet so not to mushroom the end of the 4 prong drive, it will damage the Morse taper in the headstock if it become mushroomed on the end due to using a heavy hammer.
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.... just make a wooden mallet and hit it harder thereby driving it a bit deeper and helping it grip better. ......
Accepting that using a hammer may cause other problems........
What wood would you suggest using to make a wooden mallet?
And what weight head?
MC
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Mine has an ash handle and a head in beech. if you can get hold of an old bowling bal cheaply (unlikely now) lignum vitae is good. Basically a hard wood for the head. Not oak though, tried that and it chips a lot if you hit metal as in the drive centre. Sure others will have ideas for wood as well.
pete
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for mallet heads you should use any of the following, hornbeam, apple, beech, eucalyptus, hawthorn, hard maple, plumb or pear.
exorics that can be used are jarrah, ekki, ipe, massaranduba, balau, keruing or as pete said the lignum bowling balls which will be the best solution.
here is one on ebay, http://www.ebay.co.uk/itm/Old-Lignum-Vitae-bowl-for-woodturning-/400964246914?pt=LH_DefaultDomain_3&hash=item5d5b54dd82
for the handle i would use ash.
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I just use a carvers mallet that I keep for the job. You don't need to smash the drive deeply into the wood to drive it 3-6mm depth should be sufficient in seasoned wood. As Philip has pointed out you should not tighten to much as it will cause undue wear on the bearings, this can simply be notice by over tightening the tail stock at which time you will hear a change in sound coming from the bearings.
When I teach I lock the head stock off and locate the indents made by the prongs in the wood onto the drive, with the tail stock brought up I get the student to gently rock the wood back and forth until the slack is taken out, then a little more twist of the tail stock is all that is needed. If the prong indents are deep enough and the cuts are taken efficiently then the prong should not break out, far too often initial cuts are too aggressive causing this to happen. The intermittent cuts will cause the fibers in the end grain to move slightly so until it is round I recommend a regular check of the tail center with a little tightening to take up any slack on the drive.
a mallet (http://www.ebay.co.uk/itm/like/350704347161?limghlpsr=true&hlpv=2&ops=true&viphx=1&hlpht=true&lpid=108&chn=ps&device=c&rlsatarget=&adtype=pla&crdt=0&ff3=1&ff11=ICEP3.0.0-L&ff12=67&ff13=80&ff14=108) like this is all that is needed, or turn a basic one out of a lump of Ash
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The problem I've found with really nicly made things like Lignum Vite headded mallets is no-one wants to damage them...
You've got a lathe, any sound piece of branchwood will make a mallet (maul), it's going to get ruined hitting the tang of the Drive.
So don't worry about it, use what you've got, when it's knackered just make another.
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Personally, I don't think the steb centres are worth the extra expense and the drive you get from them isn't as good as a similar size of four prong drive. Just my opinion, if you want to splash out another £40 - £50 that's up to you!
Have you considered a larger diameter four pronged drive centre instead? These are under £20.
Alternatively, how about something like this? http://www.axminster.co.uk/axminster-screw-chuck-faceplate-drive-for-c-jaws
With the centre screw removed and the drive screws added, it makes a useful drive that can be mounted in a chuck.
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One of the plus points of a steb centre is if you (or a student perhaps?)gets a catch they are less scary with a steb centre and less dangerous too.
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Steve centres are spring loaded and you need to take care when parting off.
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I've just noticed that I must be more careful and check that the i-pad predictive text hasn't taken over.
Steve was chosen for stab. Getting worse isn't it. I'll have another stab. Steve shut up for steb's sake.
Ah well as they say "silly things for simple minds".
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That makes a bit more sense now :)
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as a Steve i'll quite happily have a tool named after me, when do i start to get money for allowing use of my name? ;D
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It has to be split between ALL the Steves :)
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and all the Steb's. No no no not Steb's all the Stebs.
Apple needs to learn about the correct usage of tha apostrophe.
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.... just make a wooden mallet and hit it harder thereby driving it a bit deeper and helping it grip better. ......
Accepting that using a hammer may cause other problems........
What wood would you suggest using to make a wooden mallet?
And what weight head?
MC
I suspect that my four prong centre would NOT hold the blank for a mallet head so I'm thinking now of a copper hammer.
Such a tool would come in handy for other jobs too.
Comments?
MC
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just out of curiosity what size square are you turning that you are having trouble with and what species are they???
i turn large squares out of sycamore and beech 100% seasoned for my skittles and do occasionally have the same problem (once every couple of sets) but my steb centre is a bit past it and could do with a new one and it's usually because i've not wound the tailstock in enough.
the squares i use are 5"+ so it's understandable that taking too much in one go could spin the drive in the wood, to overcome this i've found that speeding up the wood gives it more momentum and therefore has less chance of stopping.
a sharp roughing gouge helps as well.
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just out of curiosity what size square are you turning that you are having trouble with and what species are they???
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a sharp roughing gouge helps as well.
The Ash blanks are 1.5 or 2 inches square. I'm making handles for some unhandled chisels.
The Four Prong centre is VERY old - it came with the second-hand lathe when I acquired it.
With best wishes and thanks.
MC
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why not drill your tool hole first and use a friction drive turned from another bit of wood?
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The Four Prong centre is VERY old - it came with the second-hand lathe when I acquired it.
The blades on the four prong centre are about a millimetre wide.
I'll try sharpening them with a grinding bit on my Dremel but fear the will leave it lacking symmetry.
MC
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MCB you say blades are 1mm wide. Seems odd to me.
I have one 1" dia with blades 5/16" wide and a small one 3/8" dia with blades 1/8" wide.
Dead easy to sharpen with a smoothish file. I wouldn't put them anywhere near a wheel.
For 2" square ash I would even use a two bladed drive.
I use a bit of 2" square cast off oak as a mallet.
Don't be tempted to bang the wood onto the drive once it's in the headstock, or you'll soon need new bearings.
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MCB you say blades are 1mm wide. Seems odd to me.
I have one 1" dia with blades 5/16" wide and a small one 3/8" dia with blades 1/8" wide.
Dead easy to sharpen with a smoothish file. I wouldn't put them anywhere near a wheel.
For 2" square ash I would even use a two bladed drive.
I use a bit of 2" square cast off oak as a mallet.
Don't be tempted to bang the wood onto the drive once it's in the headstock, or you'll soon need new bearings.
Each blade is approximately 10mm long and 1mm wide.
Perhaps I should have written “1mm thick” - sorry if this caused any confusion
MCB
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Another Steve here, I never use the Steb centres and have no problems with the standard drive. I would reccommend using a morse taper version of whichever style you pick. Unlike others I very occasionally sharpen mine on a small 6" grinding wheel, after many years this does mean you need to turn out the center to give enough clearance for the wings to grip the timber so for this reason I would not reccommend it unless you are happy turning metal. I have made a few centres from old drill bits. I have several sizes but use the 1" the most and find it will hold most sizes of timber. My largest is a 1 1/2 " and that holds fast almost anything.
I would never use a mallet with the timber in the lathe as this can't be good for the bearings. I have a strong tailstock on my lathes which create a lot of pressure easily.
I don't see any advantage of a spring loaded center and they are expensive.
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Frans Brown makes a good one. It fits in-between the jaws of your chuck.
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Frans Brown makes a good one. It fits in-between the jaws of your chuck.
I've been in contact with Frans Brown and he tells me that he no longer makes and sells what he calls his X-drive.
Very many thanks for the suggestion.
MC