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Another use for my homemade chuck

I have been making a batch of finials using my homemade chuck. They are to be screwed onto some 12 mm threaded steel rod, and for this they need a blind axial hole.

The chuck insert for this job is just a short length of the threaded rod. Ideally, to make sure it runs true in the chuck, the insert would be made by cutting the thread on  a bit of plain rod, leaving one end unthreaded to go in the chuck. The studding works well enough, though with a little run-out.

Threaded insert in the chuck

I start by preparing the blanks, each with a hole drilled in one end, of a diameter that will screw onto the rod fairly easily.

The running lathe draws the blanks onto the chuck. I wax the thread between items and the blanks align themselves as they go on. The variable speed is turned down and I hold the blank tightly to stop it turning. When it nears full depth on the thread I let go. It only takes a second or two. I move the toolrest out of the way to avoid getting my fingers trapped. Then I bring up the tailstock and toolrest. I have been roughing this batch down using my Alan Lacer skew chisel flat on the rest with its handle low to give a sliding and peeling cut. The middle of the curved edge takes off the waste quickly.

Roughing to cylinder with Alan Lacer skew chisel

The next job is to rough down the narrow part of the finial. I could do this with the skew too (I would have to use the smaller size because there is not enough room for the large), but I normally use a 10 mm scraper. 3 1/2 adjacent cuts give me the right width. I judge the diameter by eye using the chuck body as a reference. Dimensions are not critical.

sizing the lower part with scraper

I then plane the remaining wider part with the skew. This makes sure the widest part of the finial has a good surface without tear out from the roughing stage.

I use the skew to shape the upper part of the finial, which is like a pointed egg in shape. This can be done either with the long point or the edge. I used both on this batch – it all makes practice. Then the skew planes the lower part of the narrow section – one parallel cut to the left then one to the right to make a short taper.

Rounding over the end

Then I use a small spindle gouge to make a cove beneath the egg section, and a very small homemade gouge to make a tiny cove separating the two planed bits.

Cutting the cove with a spindle gouge

Making a tiny cove with homemade spindle gouge

Then I use my favourite 10 mm skew chisel to scrape an undercut at the bottom of the finial. This will let it fit closely to a curved surface when finished. I do this very carefully as I want the undercut to finish as close as possible to the metal thread in the chuck. I usually stop short by about half a millimeter and remove the last little bit by hand later. Occasionally I misjudge it and the point of the skew touches the thread. No harm done with a scraping cut, but that means it’s time to resharpen. I also use the edge close to the short point to plane the little fillet next to the cove beneath the egg.

Scraping the undercut

Then I move the tailstock back and use either of the skews to trim off the centre mark. The small one seems to work best. A light cut stops the finial screwing further onto the chuck, which can throw it out of true.

Trimming off the tail centre mark

A quick sand, then I grip the finial with a friction mat and switch the lathe on in reverse to let it wind off the finished job, which will be ebonised.

The completed finial

 

 

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