24
May 20

Centerline finding aid prototype

So I had an idea and I’ve not seen this around for sale anywhere so I figured I’d build it.
When learning to turn, we keep getting told to set the height of the tool rest so that the cutter is along the centerline of the bowl.

I mean, after a few you can kinda get the hang of it and just set it by eye six times until you get it right and I’m told that after a few years you can drop that down to only setting it by eye two or three times to get it right 😀 But my lathe has morse taper 2 fittings in both the spindle and the tailstock, and you can get blank MT2 arbours for various other things (it’s not just lathes that use MT2 fittings) so I bought a blank MT2 arbour and some other bits and pieces and made this.

Small voltage source, some hardware for mounting something concentrically with the arbour and a laser diode with a cross collimator and…

And now you have a centerline to set your tool rest height to.

Now that’s just a protoype so it’s got some mechanical issues (that box isn’t as rigid as a metal one would be, and it’s enormously large compared to what it needs to be, but lookit, it’s a prototype not a finished thing and anyway I mostly made it because I wanted to see if it’d work anyway.

You do need to align the laser, and if your lathe has indexing like most newer minilathes, that’s easy, you just take off the chuck and turn on the laser…

Line up the vertical laser line so it hits that indexing marker above the spindle and that’s it aligned (assuming that your headstock and tailstock are aligned, but that kind of alignment is a routine lathe thing and you can get specific tooling for it and so on).

Activate laser, raise toolrest, put scraper on tool rest, cut bowl.
What do you think? Useful training wheels for learners?


02
May 20

School day, take two

That sodding bowl was annoying me.

So, put it back on the lathe using the recess, which wasn’t completely destroyed by the catch yesterday, and re-cut the rim (and of course, half-way through that, I had another catch and the bowl jumped behind the lathe to hide in the shavings pile). Once re-seated on the chuck, I finished recutting the rim, cleaned up the lip and deepened the ogee.

Then sanding, re-staining, sanding sealer, gilt cream on the rim, lip and back while trying not to lose a finger to the dovetail jaws, and then tried out Yorkshire Grit to polish the bowl (quite impressed by that by the way).

Then, new toy, cole jaws for the lathe!

Those buttons on the jaws that hold the bowl in place, by the way, are nowhere near as soft as the name “rubber button” suggests if you accidentally stick your finger into one while the lathe is spinning…

Happily didn’t break anything, but my manicure is ruined. Cut away the ruined recess and recut a wider foot than before, and then on to sanding, staining, sealing and some shellac. The branding survived so didn’t have to rebrand it.

And rewired the shed a little so that I now have enough plugs for the lathe and lights and dragging the lathe around a bit to get better access doesn’t drag wires under the lathe or pull plugs out of sockets.

End result is what I was hoping for.

The foot’s not fantastic, but the rest is so much better.

Before:

After:


01
May 20

Every day’s a schoolday

So I thought I’d move up to a 6″ blank from the 3″ ones I’ve been practicing on so far. I had in mind as well to do some colouring work – been watching too much of woodturning Youtube I suppose. It went to plan right up until gouge touched wood for the first time, which is pretty good as these things go.

The plan was to have an ogee curve on the outside of the bowl, rising to a narrow lip and then on to a slightly wide rim with a downward sweep into a bead that the main bowl interior would cut down through. Then the outside and the rim would be stained black with bronze gilt cream in the pores to liven up the grain, and the inside would remain the natural wood colour.

It didn’t work, but you can sortof see it from here, if you squint hard enough while staring somewhere other than the screen…

I mean, the ogee is starting there. It’s just not aggressive enough on the concave portion of the cut. And the lip is twice as thick as I wanted and there’s tearout on the bead at the start of the main bowl. Problem was, after I flipped the bowl over and chucked up the recess, about twenty seconds into squaring up the face, I had a nice catch and it ripped the bowl out of the chunk jaws and flung it at the wall and it bounced back at my face. You can see the damage it did to the foot.

So after that I stuck with less aggressive cuts 🙂 But the outcome suffers for that.


The colour is also disappointing. I put on the gilt cream first, which was a mistake; should have stained it first, then sealed it (though I don’t have cellulose sealer which I might need to rectify), then done the gilt cream. But the colour of the gilt itself isn’t half bad. Like I said, I can see what I wanted to get from here, I just didn’t manage it this time.
Oh well. Next time!