I always recommend that the flange be cut off. Even though Stachiw shows supporting the inner heel, you have to remember that these were early experiments. First they pressure tested a dome with a formed flange (and of course it broke at the heel) So they reinforced the heel and the dome went deeper. Even so, a further improvement was made when Kittredge chose to cut the flange off and glue on a ring to use as a hold down. This design eliminated the highest stress area (the heel) and added years of service life to the dome- something that Stachiw could not test. Modern subs with domes (like the deep worker 2000) use straps instead of flanges.
So the moral is, even though Stachiw was the first and best work done on acrylics, not everything you see there is the best solution today. The few times I got to talk with Jerry on the phone he sometimes discussed ideas he had come up with in more recent years that were not in the book.
Regards,
Greg
--- On Thu, 5/27/10, Alan James <alanjames@xtra.co.nz> wrote:
|