old Steinway ivories

[Allen Wright]

List,

I've taken on a job of replacing a dozen or so missing ivory fronts (using
my collection of old ivories) on an old (ca. 1911) Steinway grand in
otherwise pretty good shape. Don't normally work on old uprights much
anymore, but I decided to do this partly because I enjoy doing chipped key
repairs with the acrylic kit.

I discovered when I got the keys home that they don't in fact seem to have
used ivory wafers, or linen or glue and whiting on these originally. Instead
it looks to me like the tops of the keys were scored with small grooves
front-to-back (very straight and consistent) and some sort of glue must have
been used, although I really don't see any remnants of glue.

I've been reading old journal articles trying to learn the right way to use
ivory wafers, and have gotten the clear impression that ivory will only work
using a linen undersupport. Otherwise, it will crack eventually. Yet these
keys have survived 90+ years (most of them, anyway) and look great. They
haven't even curled much. Can anyone tell me how Steinway glued these on?
Was it just hide glue?

Another thing I don't get about these keys is that there is a wood insert
about 3/4" wide and 3/16" thick right in the middle of the fronts, on top of
the keys - what was that for? Related to making the mortise?

Pardon my ignorance.

Any suggestions will be appreciated.

Allen Wright
Cincinnati, Ohio