Metal shaping on the woodlathe

[rsser]

The task is to take down a half inch MT arbour to 12mm. Over a length of about 15mm. Doesn't have to be spot-on centred; it's to mount discs of various materials running at slow speeds.

Terry Martin described using a scraper to true chuck jaw faces in an issue of AWR. I don't have a small square end scraper but could regrind a 3/8" beading tool. Would rather not.

So what does the brain trust think?

Get some W&D or emery on a paddle, spin the arbour on the lathe and 'sand' down.

Spin the arbour and file down?

[RETIRED]

Angle grinder with a sanding disc whilst rotating arbour in the chuck.

About 1 pass would do it. It is only .6 of a mil off.

[sjm]

I mounted a conventional 5/16" HSS cutting tool blank into a wooden handle and use it like a normal wood turning scraper. Works great on copper and brass, not so effective on harder materials, since it's only hand-held.

[rsser]

Thanks sjm. Good thinking. Too much effort though for a one-off.

And thanks .

The only angle grinder with sanding pad in the kit is a big cheapie and I wouldn't trust myself with that.

So I had at it with a 4" job with a metal grinding wheel, a light touch and lots of checking. The finish was pretty ugly but it cleaned up with some W&D.

Job done.
.

[Paul39]

Get some W&D or emery on a paddle, spin the arbour on the lathe and 'sand' down. Spin the arbour and file down?

Yes & Yes.

I would get a strip of cloth backed 80 grit sand paper about 10 inches long & a little wider than your cut, put on some light oil and pull tight at right angles to the slowly spinning arbor.

Sand, wipe, try, repeat. Change position of the contact area as it cuts slower. As you get closer to the right size you could go to finer grit for a more polished surface.

This should keep the area concentric and not cut too fast.

The above is standard practice in metal work to get the final dimension and finish on a shaft turned on a lathe.

Sequence - turn part on lathe, file, use abrasive paper.

[letzzzgo]

Ern, a strip of emery cloth should do the trick in use with a flat piece of timber.
I have some here you are welcome to. When do you need it?

[hughie]

I think the grinder suggestion is the way to go, .6mm is a lot for emery or a file. You could finish with a lathe file and some emery to polish it.

[issatree]

Hi ,
I've Turned Arbors down a few times as I make Drive Dogs from them.
At times I have found them to be a bit harder than just mild steel.
So I heat the end up, but I don't go to extremes, like Red Hot, let cool, slip it back in the Head Stock, take my 25mm Skew, & it turns down as easy as pie.
Sometimes I use a bit of S/ Paper on it, then some Steel Wool to polish it.
Of course, if you wish, you can Reheat, & cool it off in water.

[rsser]

Thanks guys for the tips.

In post #4 I describe what I did. Not pretty but it worked.