Natural Edge Cork Oak Bowl ...

I'm exhausted this evening but had a very good day.
I have two days free for turning - no duty at Waterfront Woodturners.
An ideal opportunity to get stuck into this big piece.
This is a 650mm diameter natural edge cork oak bowl.
The biggest bowl I've ever turned.

You can see the pics and preparation of the bowl blank here


Chris helping me getting the monster blank up on the lathe

What would I do without my greatest helper (when he is occasionally around)









Now we got to get it straight so the wings of the bowl end up equal height

















Only on a Stubby 1000 - and its not even bolted to the floor

Just manage the speed very carefully

Now this is why I bought a Stubby!

And just in case you are wondering about the shorts/knees and special 'safety' shoes just remember that the temperature is about 35deg C (95deg F) in the shade in Cape Town in February

Under my asbestos sheet workshop roof - who knows?



Part 1
Here is a short movie to show the blank rotating.
Pretty impressive isn't it.
The blank wasn't nearly as out of ballance as it appears visually.
I took great care to ballance it by carefully carving off pieces with a chainsaw.
As I worked around from the base towards the circumference I trimmed the bowl progressively with the chainsaw. This kept it in ballance and made the turning less rough.


Here is the outside of the bowl turned

It is beautifully spalted but rather punky

Sharp tools and a light cut were the order of the day

The blank turned down to 650mm diameter, having obviously started off somewhat larger





I got real brave and even cored out the centre with my Kelton

Fortunately the wood is pretty soft and punky so it wasn't too difficult

I also just removed a single core and used a wide kerf to avoid problems






Here is the centre ready to come out

It will be turned into a second bowl











Out it comes













The centre core removed













There was a great black void under part of the bark but unfortunately I had to sacrifice most of it in turning away the inside of the bowl

The deepest part remains however and there is still a lot of interest where the bark meets the wood













I spent the latter part of the evening turning out the inside so the wall thickness is somewhat thinner now but it was too late to photograph and I was too damn tired by then







More pix tomorrow








And the day afterwards I thinned the wall a little and finished off the inside shape












Look at that stunning bark


















Complete with irridiscent green lichen in parts










Part 2
Here I make the last couple of cuts on the upper sections of the inside of the bowl.
This is a very delicate opperation as one is intermittantly cutting the soft corky bark on the wings and fresh air between them. It is critical to have a very sharp chisel. In fact at this stage I resharpen between every cut. One can't take a very shallow cut because there is just too much bounce on the chisel caused by the intermittent cutting. You can see that I had to move back and restart the cut because I started off taking too shallow a cut. One must also not take too big a cut as this will just nock of large chunks of the cork bark natural edge. So be bold but not too bold! One has to hold the bowl gouge very steady as it is advanced down the inside of the wings of the bowl and try and keep the depth of cut the same all the way down.



Part 3
Here I have moved the tool-rest a little deeper into the bowl to cut deeper than the wings. It's very important to cut a nice smooth curve between the wings of the bowl and the bottom, no ridges, no flat spots and a smooth curve from top to bottom.



Part 4
Showing the use of a very simple 'bloudraad' (fencing wire) wall thickness guage!



Part 5
Here I am turning the very base of the interior of the bowl.
The way to test the interior curve of the bowl is to run ones fingers from the wing to the centre. Fingers are even more sensitive to variations in curvature than eyes

I will insert a picture of the finished bowl in a couple of weeks. It's going to take me a while to sand and finish it

9 April 2007 - Easter Monday



Part 6
Well on the advice of Peter Nicolle I took my courage in both hands and remounted the bowl on the lathe to thin the wall. I had the feeling all along that that is what I should do but Peter's comment just tipped the scales. As it turns out the bowl has definitely been improved by thining the wall and deepening it somewhat



Once that was done and I had applied a few coats of finish I took another step forward in finishing the bowl today

I reverse chucked it on the lathe






Part 7
Here I am turning the foot of the bowl to remove the screw holes and leave a nice clean foot



Here is the foot of the bowl with most of the spiggot carved away












This is the end of proceedings on the lathe

After this the bowl was removed from the lathe and the remaining portion of the spiggot removed with a mini arbourtec before finally sanding it flush








The foot pyrographed with wood type, initials and bowl number













Part 8
This is just a general view of the bowl to show how it was reverse chucked on the lathe to have the foot turned just before the bowl was removed from the lathe for the last time


And here is the bowl in the workshop

A few more coats of finish to be applied and it will be ready for the AWSA 2007 Conference gallery at the end of April