waco, I had the same problem with my #450, but found a simple cure as I lack Keith's machining skills. The late Ken Mollohan ("Molly") recommended inserting a sheet of tablet backing or shirt cardboard under the lube sizer, tracing its "footprint," poking holes for the retaining bolts, and then tightening it down. You next take a sharp utility knife and cut around that footprint. Voila! you now have a leakproof gasket. I did this years ago (after unsuccessfully monkeying with the #450's bottom) and never had another leak. Try it, as it takes less time to accomplish than writing about it.