John Rodgers on wed 13 oct 99
The one round hole and one oval hole system on the Pacifica plastic bats
have worked well for me. And should for any handmade bats if done with
precision. The oval hole allows for any minor variation as to screw
placement for bats on wheel heads on different machines.
As long as the round screwhole is a snug fit on the screwhead, all the
way around, the oval screw need fit snug only on right and left sides,
not fore and aft. It will not move.
All of this assumes of course, that the bat in general is true in its
planes and dimensions. If this is not true, then the batt will likely
wobble up and down on the wheelhead.
If you want some nice, good quality, standard bats, you might contact
Jeff Lawrence, a member of this list. He got a really nice set made up
somewhere, and being the nice fellow he is, probably wouldn't mind
sharing the source.
You can actually throw on excentric bats, ie, bats that are off-center,
oblong, square, or triangle shaped, octagonal, or what have you.You can
even throw on bats that wobble up and down, as long as they don't move
for and aft in the process. If that were the case, you would never get
the clay centered. The critical element is allowing the centering
process to find the exact center of the wheelhead shaft as it turns.
Once done, the rest is easy. In dealing with the up/down wobble, you
must determine if the wobble is in the surface of the bat or if the bat
is warped. If it is surface wobble only due to uneveness, just go ahead
and center. If the wobble is due to a warped bottom on the bat, the you
must stick a little clay under the bat and press the bat down. That will
stop the wobble. The go ahead and center.
Some potters I know squish clay out directly on the wheelhead, making it
a little wetter than usual. Then three concentric grooves are cut. Then
a bat is pressed onto the clay. The bat is stuck really tight and will
not come loose. The pot is thrown, cut off with a cutoff wire, and then
carefully picked up and set aside to dry. The bat surface is scraped,
and it is ready for the next piece of work. They will use only one bat
for a days work.
I know of one potter family whose work is done directly on the
wheelhead. There is not a bat in the place. When the work is done, it is
cut with a cutoff wire, and an lifted with pot-lifters.....special tools
made to fit the base of a wet pot in order to lift and move it. This is
mostly used for very large vessels
As for myself, I prefer throwing on plaster bats. I find that most
plaster bats I have used had a little wobble up and down, but were true
and didn't move fore and aft. So centering was easy. And when the work
was done, all I needed to do was set the bat aside for a while, and in a
short time the plaster would pull enough water from the clay to allow
the pot or whatever to simply pop right off, leaving a nice smooth
bottom. Some don't like the plaster bats and complain about plaster
chips getting into the clay. A legitimate complaint, but for me
insignificant enough that I still prefer the plaster bats.
BTW, the bats I used were created using a bat making system I got from
Axner. Worked pretty good. Easy to use.
In New Mexico