Saturday, January 10, 2015

A Handwheel For A Wood Lathe Without One

A recent wood lathe restoration project has left me with a nicely working wood lathe that lacks a handwheel for the headstock spindle.

I find myself using the cone pulley for a handwheel -- not the safest practice.

So, I'll make a wooden handwheel for the machine, using a 2" pulley as a hub.

Here's what I have to start out with.

That wood is softwood, which is not the best material for this. I'd be better off using a close-grained hardwood like maple, but I don't have any that's suitable. I'll go with the softwood, and see what sort of result I get. I can always make a new, better wheel if and when I obtain some better material.

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And here's the pulley at the drill press getting four 5/64" pilot holes drilled for fastener locations.

Starting a drill on a sloping surface like that is a bit of an iffy proposition. I was able to get a reasonably precise, if not entirely perfect result.

Here I've bored the pilot holes out to No. 25 drill diameter, for tapping 10-24.

Before tapping the fastener holes, I faced off the rim of the pulley, to ensure that the handwheel will run true.

And here we are with the pulley's fastener holes having just been tapped 10-24.

Here's the wooden handwheel blank assembled to the pulley, and mounted for turning.

The screws are 10-24 x 1 1/2" round head, with No. 10 SAE flat washers under their heads. I installed the screws with blue threadlocker, so they won't loosen off on me.

And here's the finished item, turned, sanded and ready for installation.

Finally, here's the handwheel mounted on the outboard end of the headstock's spindle.

Much better.

The handwheel isn't perfectly balanced. At the lathe's highest speed, there's a slight but perceptible vibration. I've yet to have had need of that speed, so I'll just work with the handwheel as it is for awhile, and see if it's satisfactory otherwise. I can look into how I might correct the imbalance later.

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Further To Imbalance -- SUNDAY, JANUARY 11, 2015

I put a dial indicator on the rim of the wheel, and discovered about 0.030" of radial runout. That probably came about while sanding the rim of the wheel, and no doubt accounts for much, if not all, of the wheel's imbalance.

Sanding on the wood lathe will tend to remove material non-uniformly, according to density/hardness variations around the circumference of the object being sanded. There's a 'path-of-least-resistance' effect that results in out-of-roundness. For a static, artisanal turning, the out-of-roundness is unlikely to be perceptible, or to matter at all to the usefulness/quality of the finished item. For a machine part, the out-of-roundness may matter, as it appears to here.

What I'll do is is I'll carefully re-turn the rim of the wheel with a sharp gouge, and forego sanding it. That should result in a truer wheel. We'll see.

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I re-turned the rim of the wheel and left it unsanded. The measured radial run-out is now about 0.012", and the wheel's balance seems to be slightly improved.

Anyway, the arrangement is perfectly acceptable. I'm not going to fiddle with it any further. I'll just give the handwheel feature a good trial as I continue to use the lathe, and see how I like it overall.

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A Small Improvement -- MONDAY, JANUARY 12, 2015

I deleted the round head screws and flat washers that I had used to fasten the wheel to the pulley, and replaced them with flat head screws.

Now there's nothing protruding from the face of the wheel when I use the wheel as a 'brake'.

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I Forgot Something -- MONDAY, JANUARY 19, 2015

A hole for the knockout bar to go through.

There. Now the wheel has an 11mm diameter hole through it for the 10mm diameter knockout bar to slide through.

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