First things first, this is not me being creative. I just copied the idea from a project in last months woodturning magazine. But I liked the project and wanted to have a go. It was also an opportunity to turn something BIG. Certainly the biggest turning I've attempted ,and right at the limit of my lathe's capacity.
It started out life as a large lump of oak beam.
My younger brother builds and renovates houses, and some time ago he gave me the oak. It was an off-cut from a structural beam in a very nice extension he built. It's been sat in my garage for sometime, waiting for me to figure out what to do with it.
This section is about 50cm long, as long as my lathe bed would allow, and so large in cross section, I couldn't get the banjo underneath it until a section had bee turned to round. Obviously I set the lathe at it's slowest speed (500rpm) and even that was a little daunting. This really was a big heavy lump of oak spinning at 500 rpm.
This made a lot of shavings.
I then tapered the shape to form the base and started to shape beads down the length
My first set were a little rough, and I got neater as I practised, so I ended up returning to reshape the worst beads until I was reasonably satisfied with the look
The next challenge was to produce the head shape. The article made is sound easy to just cut out the curved top section from a huge block of wood. But my bandsaw struggled. I later decided that my blade was a little blunt and switched it for a new one, which did seem better. But not before I'd struggled with this section.
The idea is to use the cut out piece to be a friction drive on the lathe, this worked well enough.
The hole through the middle was as large as I could manage through such a large depth of wood. The article didn't talk about forming the hole, but I realised that my larger diameter bits just wouldn't have the length to go all the way through, and trying to go from both sides and meet in the middle is way too hard. So I used a big auger bit, which was a little scary since even mounted squarely in my drill press, the length meant tiny imprecision lead to large wobble at the tip. I over came this by starting with tip pressed a little against the wood. My drill press doesn't even have enough travel in the head to go through in one, so I had to keep moving the platform up to cut through in stages.
Shaping the exterior of the head section was easy enough, but because of the mess I made with the band saw i felt i needed to clean up the top surface. This meant holding it on the spigot that would ultimately sit in the neck section. And allowing the off-centre top to whip around whilst I tried to carefully use a bowl gouge to clean up. This was difficult since the out of balance nature of the top introduced vibrations, and i couldn't get banjo support too close, so it was a little like deep hollowing. Ultimately I locked the headstock in place and cleaned up the rest of the surface with my power sander (sander attachment in flexible shaft attached to drill) The last thing on the head section was to carve a series of curving lines out from the holes and all over the surface. The article did this with a power carver, but not having one of those I used a carbide bit in my rotary tool. First I drew the patter in pencil, then just followed the lines with the rotary tool freehand. This worked pretty well, and just needed a little sanding to clean off some frayed edges.
I didn't remember to take more pictures of forming the head, or any of the wide neck piece. The neck piece was just a 50mm wide section of the oak, cut to be not quite square, so it could be turned to have two flat sided but taper in a curve on top and bottom surfaces to two rounded ends.
See here the final assembled piece
And finally I got to play with a blowtorch to ebonise the piece. Party to protect it from the elements, but mostly to contrast out the beads and the carving. This was good fun and weirdly like using a spray gun to 'paint' on the blackened surface. Particularly interesting is how fast the surface blackens, while even very shallow carved lines or the base of beads stayed un touched.
At last it was finished
I enjoyed this project, and I'm fairly pleased with the results. It may be sometime before I have the wood to turn anything quite so large again.