Thursday, March 7, 2013

Holly's Walnut Bowl-Pt.2: Preliminary shaping

Good Morning All,

I've been looking at the turning blank since Tuesday and I've decided to shape it into a calabash bowl. Calabash bowls have a narrow opening at the top that is smaller in diameter than the widest part of the bowl. I've never made one before and I think this shape will fit the shape of the turning blank. So off we go.

Shaping the bottom
Since the blank is still attached to the faceplate I decided to shape the bottom of the bowl first.  So I took the whole thing back to the wood shop and re-attached it to the lathe and the first thing I noticed was an ominous looking series of cracks in the surface of the blank. The bottom needed to be trued up and the bark was still attached to the blank too. These are all problematic features and have to be dealt with first:

I like to take a straight edge to check the flatness of the bottom of bowls and platters. It can be difficult to see small subtleties and it's important for the bottom of the bowl to be flat so it won't spin on a flat surface:

I've gently shaved the bottom flat and I've also located the center of the foot and marked off a 2 inch diameter circle and a 3 inch diameter circle. I'm not sure yet just how I'm going to mount the bottom of the bowl onto the lathe and so these two circles will let me either center a small faceplate or create a recess for my Nova chuck. Those can stay there for the time being:

 In this photo you can see the flattened bottom clearly. I've roughly marked the widest part of the bowl in white pencil. Approximately 1/3 of the bowl will sit below this mark and 2/3 will sit above this mark:

Time to begin shaping the blank. There is a lot of wood to be removed before we get to our final shape:

You can see in this photo how I've rounded off the upper 2/3 in preparation for really narrowing this portion of the bowl. 

Here is the bowl several minutes later:

And about 10 minutes later:

 Time to take the blank off the lathe and stand it up to see clearly what the shape looks like. I think the general shape of the bowl is good. My next step is to shape the bottom a little more, cut a recess in the bottom for my Nova Chuck and smooth the wood. I like to get the bottom of any bowl nearly finished before I flip it over and re mount it. It's much easier to do this now rather than later:

Here I'm cutting a recess in the foot of the bowl with my tailstock removed and a drill chuck inserted into it's place. You can see the big Forstner bit I'm using for this:

The Forstner bit will produce a recess with straight sides and we'll need to dovetail the sides so the chuck will fit into the recess more securely. I'm going to do this with the small parting tool you see in the photo. This takes only a minute or two to accomplish and it makes the chuck sit more firmly in the recess of the bowl:

Here is the finished recess:

This photo shows how I've cleaned up the bottom and sanded it smooth. The bark is still there but it's firmly attached and very smooth now so I think I'll just leave it:

I've taken the bowl off the lathe and removed the faceplate. In this photo you can see the chuck being screwed into the recess in the bottom of the bowl:

And I've flipped the bowl over and remounted it on the lathe. In the photo you can also see cracking radiating out from the center of the bowl. The pith of the tree is causing this and it has to be removed so I'm next going to remove about the top 1/2 layer of wood and you can see how I've marked that off in the photo:

Here's another problem that has just shown itself-a branch. You can see it at the top of the bowl. This will cause problems as well so I've begun removing it as well. I've also cut another recess in the bowl to help the wood fibers relax a little:

Here is the blank with the top 1/2 inch of wood removed and I've gotten more of the branch removed as well:

 Here is a side view of the photo. I'm hoping that the radial cracking will ease up now that I've removed the pith.
The top of the bowl needs to be narrowed and the diameter of the bowl needs to be narrowed too and so tomorrow that's what we'll work on.

I'm going to leave this out in the workshop and stop here for the day.

See you tomorrow,


  1. Thanks again! It's great to follow your project, even though you had some problems too. I always somehow find a branch at all of my turning projects... :/

  2. Hi Saaara,
    Thanks for your comment. Many years ago I was turning a mahogany block into a bowl when all of a sudden it exploded in a million pieces and my turning chisel flew right past my face. It had a huge rotten area inside of it that couldn't be seen from the outside of the blank. Sometimes the tree can grow around a defect or branch and years later when someone mounts it on the their lathe, well, they're in for a big surprise if they try to turn it.
    I just went out to the wood shop to check on the bowl and the cracks have gotten smaller so I'm hopeful that they'll either shrink away or I'll be able to cut them away as I shape the bowl. Come back tomorrow as I am going to do a lot more shaping on the bowl and we'll see how it comes out. Best Always, Vickie