Alright, back on track. Lets get to making the globe for a Christmas Ornament!
There are two ways to approach the design elements of any turning project. You can either work from a sketch, or sculpt your piece as you work at the lathe. There have only been a handful of instances when I work from a drawing. That’s not to say that I don’t sketch regularly. I like to immerse myself in and around good design and art regularly. This is critical to making something that is pleasing to the eye and has a spirit of it’s own. Bad design is thrown into the trash pile in my shop and unfortunately makes for very time consuming firewood.
So, onward to making chips! Before we got to this point, I mounted the wood onto a glue block. The glue blocks are made of Poplar and the globe I’m making is Bradford Pear.
For shaping the globe, I mainly use a 3/8 bowl gouge with an Elsworth grind. While this may sound a bit hippy, I develop the form of the globe by hearing what shape the piece wants to be. I work towards a pleasing shape and visualize a center line around equator of the globe. If I want a symmetrical piece, I establish the “equator” and begin to mimic the right half (farther from the headstock) to the left half (closer to the headstock). Once I get the shape established, I shear scrape the surface with the wing of the gouge and sand the piece appropriately. I generally start around 220 grit and work up to 600 grit before starting with Scotch Brite. I finish sanding with the white Scotch Brite and then burnish the surface with shavings from the piece. Before I start hollowing, I apply a coat of paste wax to the surface and buff again. The last step before hollowing the globe is to drill out the center with a 3/8″ drill. Reduce the lathe speed and smoothly advance the drill through the globe.
Apparently, I got just a bit too aggressive with this piece and it popped off the glue block. You can see that the opening of the globe was damaged when this happened. Now I have to figure out how to finish the globe… Don’t worry, I know what to do!
Little did I know I’d also be giving a lesson on jam chucks in this tutorial. I can’t over emphasis the importance of being able to make a jam chuck. Being able to make these will be a huge aid and could even get you out of a uhhhh…gulp…detour you didn’t think you’d be taking.
Since I had already drilled my 3/8″ hole through the globe, I used a jam chuck I had previously made for this size. My first step after mounting the jam chuck into my scroll chuck was to press the globe onto the tennon of the jam chuck. I then cleaned up the opening that was damaged when the globe decided to free itself from the glue block. Once that was finished I made a new jam chuck to fit the opening I just worked on.
Here are the steps I took to make this jam chuck:
- I left the glue block I was using in the scroll chuck and turned a tennon larger in diameter than the opening in the globe.
- I form the tennon with a tapper on it with the smaller diameter farther away from the headstock.
- With the lathe off I check the fit of the tennon. If the globe just barely fits onto the tennon, then I have a great starting point. Turn the lathe on and firmly hold the globe against the tennon. You will see a polished section develop on the tennon. This is the exact ID of the opening in the globe.
- With the reference point established, reduce the rest of the tennon just shy of this diameter and check your fit once more.
- If the globe just snugs up against the large face of your jam chuck, then you’re done. If the tennon is still too big, then take off just a little more material and check again until a very snug fit is achieved.
As always, please feel free to comment or ask questions. If you have made or make an ornament, send me a picture. I’d love to see how it turned out!