OneWay Chuck Spur drive maintenance

interesting

GaryG in MD

I would not have guessed this. Good to know.

What's the purpose of the spring-loaded center?

Ellis Walentine

The answer is probably obvious but I don't understand. Or maybe I never thought of spur centers this way.

Ellis

Re: What's the purpose of the spring-loaded center

Dave Paine

I have two spur drives. This OneWay and a Penn State drive which mounts in the MT2 taper.

Both have spring loaded pins. I think this is so that the spurs are able to make contact with the wood.

If the pin were fixed, a small hole would be needed for the pin to seat before the spurs would engage.

Even though my spur drives have spring action, I like to drill a small shallow 1/4in hole for the pin to fully seat in the wood. I feel this helps to keep the piece from coming off if I have a catch.

Re: What's the purpose of the spring-loaded center

John K Jordan

I think the spring loaded center pin allows the spur or other type of center to seat more easily on different types of wood. A pin without spring loading may work fine in soft wood but would have a difficult time seating in very hard wood, perhaps even keeping the spurs from contacting. One with a spring could seat easier.

Also, a rigid center pin can easily split brittle wood on a thin spindle. I always drill a small locator hole in the center of both ends. (I use a hand-held gimlet, a "cordless drill" as someone commented once in a demo!) If the pin is not spring loaded and the hole is not big enough the conical point on a rigid pin can split a thin blank can as the tailstock is tightened.

I generally use steb centers for thin spindles, both for the drive and tailstock ends (the 1/2" Sorby live center). These all have spring-loaded pins. The pins for these can be pulled out with pliers.

JKJ

One word of caution

Sergio

I had a oneway spr drive now gone.

One day the point did not want to move, so I tightened the sping with the set screw in the back. Nothing, thus i tightened it a little more. Nothing. The point must have been gummed up so i decided to clean it. Tried to loosen the set screw that hold the poind in place and took a certain strenght since there must have been a sort of thread locked put at the factory. While loosening, suddenly i imagine when the screw passed behyond the sides of the flat, the point sprang like a projectile almost going through my head. So make sure that the spring is loose as it can be before freeing the point.

It is designed....

Brian Roberts

to provide an easy center finding capability.

Locate the center on your blank and put a small mark with an awl......just a slight mark is all that is necessary.... then set the spring loaded center on the mark (with the turning blank sitting on the bench NOT in the lathe) and seat the spurs with a rawhide or wooden mallet. The center pin retracts as it is designed to.....less chance of splitting.

It's what I was taught......others may disagree.

If the spurs don't hold the blank when you get a catch...that center point isn't gonna do much.....ya got other problems....perhaps.....

Re: One word of caution

John C Lucas

The idea on some is to be able loosen the spindle for inspection without turning the lathe off. I do that on productuion runs bjt seldom on others. The one problem with springs is if they are too strong it creates chatter on thin spindles. I gave away my smaller steb center because of this.

Good explanation, Brian

Ellis Walentine

Very plausible. Not having ever used a spring-loaded center, I'm trying to imagine how it would allow me to mount some of the dense exotics that I often turn. I'm used to ripping blank square, then bandsawing shallow kerfs in the end to seat the spurs. Since my center point is fixed, I have usually drilled a small hole at the intersection of the kerfs to accommodate it. I can now see how a spring-loaded point would eliminate the need to do that. Thanks.

Ellis

Tension is good for tiny spindles

Ken Vaughan

While I have tinkered with the tension on the pin, putting long thin spindles in a bit of tension works better than compression or cantilever. LMS sells a live center with a Jacobs Chuck. Draw bar on the tailstock and collet at the headstock. Limits are in the inertia on the Jacob Chuck end. Sloooowww speed changes when the spindle (knitting needles) get thin.

There are practical limits on each technique.

Re: Tension is good for tiny spindles

John C Lucas

I played around with draw bars and tailstock tension just a little. Too much hassle. And like you said starting and stopping the lathe will break it in a heart beat. What you need is to have the chuck in the tailstock geared to the headstock chuck or spor drive. I made some sketches once but never needed it enough to build it

Permits hot changing work pieces

Geoff Whaling

A spring loaded center pin in a drive / live center permits hot changing work pieces in production spindle turning, particularly useful with a conical drive center.

The work piece can be safely centered while the lathe is still running. Position pre-marked center on pin in head stock drive then to pin in tail stock - bring up tail stock. While between pins only it acts as a clutch, add pressure from tail stock engages drives.

I drive a lot of my small spindle work between two point centers only - not Steb centers or conventional prongs. Works very well as the friction from the points is enough to drive the small spindles. Quite surprising how little pressure is required from the tail stock for the spindle cuts required to make small spindles.