The Knob.

 

        A hollow form from Kauri pine.

 

 

This Kauri pine had to be removed to make way for a new building and the very generous bloke who was tasked with the job offered to recover the timber for me. Initially I was only interested in the main log for milling into boards but Darryl also produced the top section of the log which looked interesting. As described in the sketch here, the tree was 'topped' at some point to keep it's height down and then lived on to produce "The Knob" which proved to be an amazing bit of timber for one that is generally very plain and boring.
 
The Knob as I received it.
Mounted it on my biggest face-plate with lots of long screws as I couldn't tell just how bad the rot was up further.
Mounted on the Stubby - one of the main things I love about this lathe is being able to use the tailstock for stability on large, unbalanced pieces like this.
I did most of the roughing down with a home-made carbon tipped tool - makes the job easy on me but it's hard on the lathe, toolrest and the timber. As soon as I have enough balance I revert to a bowl or spindle roughing gouge.
A rapidly spinning lump of wood this size can be daunting at times!
As soon as the first sign of the 'topped' section showed through, I had to refine my final shape from what I had. Wasn't real happy with it at that point but taking more off that area could have lost the top altogether.
With a tenon left on the top of the form, I reversed it onto a chuck so I could turn the base to shape. Note the spalting from the base up from the rotten heart.
Turned down to the final shape with a tenon left for remounting on a chuck with large bowl jaws.
Started to worry when I tried to run a 50mm Forstner bit through it - only had real wood for about 30mm.
The inside turned out to be a mixture of rotten pulp and resin that defied normal hollowing. Was more a case of hack and vacuum right until the last 50mm or so of the largest diameter.
The bark inclusions were doused with CA and the final rough-out was wrapped in paper to avoid cracking and left for about 9 months to dry.
 

 

 

 
Fortunately there was minimal cracking and very little distortion and the piece was re-trued with little trouble. All the voids were filled with ebony dust and CA and the inside sprayed with flat black enamel to give it the bottomless look. It took about 15 coats of wipe-on poly and sanding followed by a buffing with traditional wax to get the finish I was after.

 

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