This was a commission from my local pharmacist, who supplied his own piece of timber - a 27" long x 22" wide x 9" thick intersection of three trunks, and it had been sat in his shed for 15years getting drier and harder. The largest blank that I was able to cut from it was 19" diameter x 9" thick, but the surface chosen to be the top of the bowl was far too uneven to accept a faceplate, so work started by fixing a 6" faceplate to the base, with four 2"x1/4" coach screws. This allowed me to get a bit of weight off the blank by truing up the outside, and then to sink a socket into the top of it. I had to cut into the bowl for a good few inches before I found a surface free of voids to form the socket, and my chuck had to be lined up with one of the voids in the side so that a chuck key could reach the chuck.
Cutting the depth was tricky, as how the heck do you measure depth with such an uneven rim? I settled for calculating the depth of the coach-screw holes in relation to the foot of the bowl, then added 5/8" for the thickness of the bottom - this came to a tad over 2". Next I put the bowl the right way up on my bench and put a house-brick either side of it with a wooden beam going across the top. I took a measurement from the beam to the bench-top (9"), deducted a tad over 2" and the difference (7") was how deep the inside of the bowl should be below the beam. At that point I'd cut down into the bowl to 4" deep, so there was another 3" to go, but obviously, once the bowl was back on the lathe I wasn't going to be able to use the bricks-and-beam. The crucial thing was to know that I still had 3" to go! I simply chose two depressions in the rim of the bowl and put a 2ft rule across, which effectively marked the diameter and from this I was able to measure depth at the bowl's centre. I put masking tape on these depressions and pencil-marked the exact positions for the rule, so that each time I checked the depth I was measuring from exactly the same position....it worked perfectly!
With the inside cut and sanded, the bowl was reversed onto a 12" diameter log with its end rounded over and clad in non-slip fabric, the bowl being pushed into place with the tailstock. I cleaned up the bottom of the bowl to the bottom of the original faceplate holes and left a 3/4" stub to be later cut away and sanded.
The finish is 1 coat of wax oil and (so far) one coat of micro-crystaline wax....a few more coats of wax will follow.
C&C always welcome.
