How high should centers be?

discussion of the niceties of turning on a bow, bungee or pole lathe.

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How high should centers be?

Postby robgorrell » Thu Oct 13, 2011 3:07 am

Hi gang. I have been gathering advise from this forum on my lathe and there seems to be a difference of opinion as to the height of the centers. One group, both as advised on here and on some youtube videos uses a lathe that is "nipple high" (fun term Gavin). The other group, as seen in a number of magazines and other sources, shows pole lathes with the regular power lathe height.

What are the pro's and con's of the two schools of thought?

Rob
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Re: How high should centers be?

Postby robin wood » Thu Oct 13, 2011 8:13 am

Most spindle lathes follow Mike Abbotts plans and are relatively low. When I started bowl turning I looked at old pictures of George Lailey and reckoned his centre was armpit height so that is what I go for and most others since have done similar. If you are only a hobby turner it probably doesn't make a whole lot of difference but if you plan working this way a lot then the stooped posture typical of power lathe turners is very poor for your body. I remember early on meeting a good professional turner Kieth Rowley at a show and he had been stopped over his lathe for so many years his head and neck seemed stuck in that position.
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Re: How high should centers be?

Postby HughSpencer » Thu Oct 13, 2011 10:28 am

I have made three lathes and I have to say that making the bed top level with the top of your hip and the poppet centres around 8 to 10 inches above that is about right. I tend to put my elbow on the left hand end of the tool rest at times. I'd point out that for women, the nipple measure is not a very stable measuring point - indeed on some men it isn't either!
I made one along the lines of Mike Abbott's plan in his second book for my boys to use. As it is a bit too low on its highest setting for me, it does give me back ache.
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Re: How high should centers be?

Postby robgorrell » Thu Oct 13, 2011 12:02 pm

I have only used the one I built a couple times. It does feel awfully low now though. The centers are about elbow height. I am going to raise it up on a couple of timbers I have out back and give that a try. Currently it is bolted down so it wouldn't want to move, but it is too close to the wall.
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Re: How high should centers be?

Postby jrccaim » Fri Oct 14, 2011 3:26 am

As Robin said, doesen't make much difference. The larger the center height the larger the work you can turn, but the also the more flex in the lathe. I'd say 15 cm to start with. This is the canonical "six inch lathe" beloved by manufaturers. If you need at some point to turn a bigger piece, just make some taller poppets and pop them in.
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Re: How high should centers be?

Postby SeanHellman » Fri Oct 14, 2011 5:58 pm

I have got higher over the years. I want to stand upright and not stoop
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Re: How high should centers be?

Postby jrccaim » Sun Oct 23, 2011 4:04 am

SeanHellman wrote:I have got higher over the years. I want to stand upright and not stoop


Oh, yes indeedy, do I agree with you. But I make the supports higher, not the centers (poppets).
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Re: How high should centers be?

Postby robgorrell » Mon Oct 24, 2011 2:40 pm

I added about 9 inches of wood block under the feet of the lathe which gets the centers up to about 1-2" below nipple height. Wow that is high. But I can see the advantage in leg comfort right away. The lathe flexes torsionally more than I want now that it is not bolted down. I added a base plate under the whole lathe that takes care of most of the problem with a little shimming.

Haven't had much of a chance to really try to use it yet. I'll keep you posted. Too many irons, not enough fire.

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Re: How high should centers be?

Postby woodness sake » Sat Oct 03, 2015 1:44 am

Relax. Stand with your right palm flat on your stomach, thumb up and resting in the notch in your rib cage. Centers height should be even with the nobby tip of your elbow. For spindle turning, the top of your tool rest should be just below the centers. This will keep you standing upright so your posture doesn't go bad and it will give you good lateral range for longer or reverse hand turnings.
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Re: How high should centers be?

Postby Bob_Fleet » Sun Oct 04, 2015 3:22 pm

woodness sake wrote: Centers height should be even with the nobby tip of your elbow.
That's the measure I use when folk make their lathes at Wooplaw.
Stand and bend your elbow - the tip's the height for the spindle centres.

Without having to change the lathe or poppet heights you can get a bit of adjustment by changing the height of the tool rest too.
It means holding your tools at a different angle of attack though if you go higher or lower, but a small adjustment makes quite a bit of difference in the angle you hold them and thus the height.

Horses for courses.
I advise our folk to consider their first lathe as the prototype and find out all of it's bad habits so you can avoid them in the next one.

Calculation - Leonardo Da Vinci, that well known pole-lather, no less - around 1490 - LINK

Shoulder height - (total less chin to top of head is 7/8th your height.)
Elbow to armpit is 1/8th your height.
Hence - elbow is 3/4 your height.

So you want to set your spindles at 3/4 of your height.
I'll need to measure mine now just to see how close that is.
Enjoy.
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Re: How high should centers be?

Postby robgorrell » Mon Oct 05, 2015 7:00 pm

After a long spell away from wood I am building pole-lathe 3.0. I was given some decent oak timbers about 3" thick by 7 inches wide. I don't think this lathe is going to twist and dance like the last one. I will try to get some pics online soon.
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Re: How high should centers be?

Postby ron.d » Mon Oct 05, 2015 7:48 pm

Bob, I have just followed your link and according to Leonardo the distance from the hairline to your chin is one tenth the height of a man. By that reckoning I must be getting taller by the day.
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Re: How high should centers be?

Postby Bob_Fleet » Tue Oct 06, 2015 12:24 am

Ahah.
That means that from your hairline to the top of your head must be 1/40th your height.
How does that work if you're bald?

As long as the centres are not at half your height then things won't get in the way.

Getting a bit off topic here but as long as it's comfortable then basically the height is right.
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