Turning Archive

Subject:
Supporting things with a live center *PIC*

John K Jordan
Someone on another forum asked about making something to fit the tapered socket in a Oneway live center after the pin was removed. I often make #2 Morse tapers from wood and decided to make a couple from Lignum Vitae to fit the Oneway.

I understand the pin in these live centers and clones are #0 Morse taper but I didn't measure to verify. I wrote some notes and took some photos. I decided to add some other ways to hold things with live centers.

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, Lignum Vitae is nice for things like this since it is hard, extremely strong, cuts cleanly, and is self-lubricating.

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.

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.

I think I mentioned elsewhere that 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.

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 pieces to 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.

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.

Any other useful techniques?

JKJ

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