I've done many of these "tube around the end" grands over the
years; they're really easy.  Here's one way:

1. Remove the old gasket.  It was held down with thick shellac.
(Hopefully no one has used something else in the mean time.)

2. Stick a piece of masking tape over the casting, covering the
casting completely.

3. With a ball-point pen, draw in the holes where the dents are,
and also trace around the outside edges of the gasket.  Pencil
works fine, too.

4. Remove the masking tape, and stick it to the new leather you
will use for the new gasket.

5. Using your leather punch, punch out the holes, copying the
exterior shape of the new gasket as well.

6. Clean off casting and vacuum holes.

7. Stick down the new gasket to the cleaned-off old casting using
thick shellac _only._  Do not stick it to the top casting or to
both castings, ever.  If some lazy corner-cutter glued the top one
to the bottom one before, you do not have to repeat his mistake;
just clean off the top casting.  They seal just fine.

8. Replace the springs to hold it tight while the shellac hardens.

My Duo-Art pianos are all "tube around the ends", my machinist
regularly makes copies of the castings, I install them whenever
a customer is willing to have it done.  I think they're really neat.

On the other hand, the masking tape pattern process works just as
well on pianos that are tubed through the keys: simple, easy, fast.

Bruce Grimes