Supporting things with a live center

[John K Jordan]

This is in part a response to this thread where I considered turning a #1 Morse taper on a piece of Lignum Vitae to fit into the Oneway live center in place of the removable point: https://sawmillcreek.org/showthread....55#post2871155

I knocked the points out of a Oneway live center and a couple of clones. The points and tapers are identical. BTW, in their wisdom, the Oneway people built their live center so a common 1/4" knockout bar will not fit. Perhaps there is a metric reason for this. The clones don't have this "problem."

I measured both ends of the tapered point and set two calipers. I used a parting tool to size a piece of Lignum Vitae the with the proper spacing. BTW, I like to use Lignum Vitae for things like this since it is hard, extremely strong, cuts cleanly, and is self-lubricating.

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I then turned away the wood between the grooves, peeling with a skew chisel until the taper was approximate, extending the high end a little for some extra space. With the lathe running at low speed, I held the live center with a rod through the locking holes to keep it from spinning, and pressed the pin socket onto the taper. This burnishes any high spots, marking them so I could trim them away. Trimming needs only extremely light cuts - too much and you start over.

When close, I relieved the center a bit with a parting tool. I pressed the live center again and looked at the burnished marks on the wood. I trimmed again where needed and repeated until I saw two well burnished rings, one high and one low. With the lathe off, I pressed the center onto the taper and tried to wiggle it back and forth to make sure the fit was good.

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I turned a couple of these from Lignum Vitae. One I made as a small diameter extension with a kind-of-flat end that could hold something just by pressure, or be pointed or cupped to fit a specific task. I left the second one a larger diameter so it could be shaped as needed. I use a live center as a drive center to shape pieces like this. The second center in this photo (the clone) shows the larger piece in place along with a piece of thick wire through the locking holes to keep it from spinning. Spin that in the headstock to custom turn as needed. The first center is shown along with the smaller diameter extension.

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As I mentioned elsewhere, my favorite live center for the flexibility is the Nova. It has a #2 Morse taper which makes it easy to hold a variety of points and attachments. Those in the back of this photo are some that come with the center. Those in the front are various pieces I've shaped for specific uses, such as holding a long spindle with a small hole drilled on one end.

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The long piece mounted in the center is what I use to hold bowl and platter blanks by friction between the live center and a faceplate or the open jaws of a chuck. I use this method to cut a dovetailed recess on one side of the blank. (I flatten both sides of these blanks first so they are perfectly parallel.) The long pressure extension give me lots of working room to cut the recess and shape dovetail.

Another way to make custom piecesto fit on a Oneway live center (or clone) is to drill a hole and thread with a 3/4"x10 tap. This pictures shows a couple of those and the tap I use. Also is another pressure attachment as per Mark StLeger - simply drill a 3/4" hole in a golf ball with a Forstner bit and use it to hold something with pressure. A short block of wood would work too.

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One more thing: Nova also sells a threaded adapter with a short #2MT that fits nicely into their live center. This one is threaded to 1-1/4"x8, the same as the spindle thread on my larger lathes. It can hold a chuck, faceplate, or anything else that will thread onto the lathe spindle. I wouldn't want to turn very much on a heavy piece held in a chuck in the tailstock, but it is great for other uses. For example, if the piece still in the chuck needs to be precisely centered on a vacuum chuck or jam chuck this makes it easy. If you already have the center, this adapter can be used instead of the more traditional tailstock adapter with the longer #2MT shown behind the center.

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JKJ

[robert baccus]

These are useful for sure. I also find the big screw-on cone for the oneway extremely useful used normally or reversed for centering hollow forms and centering square shafts quickly.

[Dave Bunge]

Thanks for the good tips and detailed write up.

What is the chuck you're using in the picture below?

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[John K Jordan]

Thanks for the good tips and detailed write up.
What is the chuck you're using in the picture below?

You are very welcome. I cut morse tapers a lot to hold thin spindles.

That is a Teknatool Supernova2 with 35mm jaws, perfect for holding small squares. But this one was just barely big enough! Since I turn small squares a lot I keep two chucks with these jaws.

JKJ

[Peter Blair]

Very nice John. I'm sure it will be most helpful to a lot of turners. From what I have read here and on the other thread I now have a few ideas to try. I will be making mine from mild steel and I just may try to find a #1 taper to use as a guide. One thing John, the Lignum Vitae you use, do you just use the light coloured part. The large chunk I have is quite yellow or very dark brown where yours seems more in between these colors.

[John K Jordan]

... the Lignum Vitae you use, do you just use the light coloured part. The large chunk I have is quite yellow or very dark brown where yours seems more in between these colors.

All of mine is nearly the same color, well all of the Genuine Lignum Vitae looks close to the same and all of the Argentine Lignum Vitae looks close to the same, somewhat lighter than the Genuine. None of what I have has both light and dark.

For those who haven't turned Lignum Vitae, it's not difficult in spite of it's hardness, about three times that of White Oak. It's a pain to sand since the waxy sawdust loads up the sandpaper quickly.

JKJ

[robert baccus]

Lignum Vitae is great for turning in general--pretty and hard for fixtures. Hardest in the world in the book, used for prop shaft bearings in every nuke sub we have, in fact for almost all ships small and large as it is 30% waxes and oils. It must be used wet for bearings. Hard to sand but hardly needs it if you do good tool work--does wet sand like many tropicals if soapy water is used. Pitch pine (s. pine heartwood) also benefits from this wet sanding tip.

[John K Jordan]

...Hardest in the world in the book...

I've read that often. I think what they usually mean it's the hardest widely available commercial wood. Some others are reported to be harder than Lignum Vitae but .


According to the Wood Database's list (https://www.wood-database.com/wood-a...rdest-woods/):
Lignum Vitae (Guaiacum officinale) is Janka 4,390 lbf
(Keeping in mind all Janka numbers are averages and can vary maybe +/-10%, even in the same tree!)

Quebracho(Schinopsis spp.) is Janka 4,570

Australian Buloke is Janka 5060 according to Hitchcock and King:
"An ironwood tree that is native to Australia, this wood comes from a species of tree occurring across most of Eastern and Southern Australia. Known as the hardest wood in the world" https://www.hitchcockandking.co.uk/h...t-woods-world/

Probably can't get those but I have turned Gidgee from Australia, right up there with LV at Janka 4270. It is not oily/waxy though.

I've used Lignum Vitae to machine brackets and things, including a critical missing part for my Robland sliding table for the table saw, something I would have otherwise milled from aluminum. I found its weight useful for the handles to give a better balance on conductor's batons I turned. Makes a nice finger top. I even made a kind of unique shallow bowl from it - a tiny thing about an inch across to fit on the end of a flat stick held under the thigh while seated - this was the bearing for a "supported" spindle for spinning very fine fibers. I put a smooth aluminum tip in the bottom of the spindle and the naturally lubricated Lignum Vitae let it spin nicely.

JKJ

[Peter Blair]

John you are a treasure trove of information and the way you share it is wonderful. I had meant to include a photo of the 'chunk' of LV i have had in my possession for about 45 years but have a bad back at present and just can's bend over to dig it out. I will post a photo to this thread as soon as I can get to it though. As an apprentice boat builder in the 60's I too witnessed the use of LV in Shaft Logs and at that time it was no where near as expensive as it is today. the piece I have was a scrap from one of those jobs. I just crawled out to the shop and dug the piece out and here are a couple of photos that show the light and dark wood.
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