This engraved design (PM-MK) is in the old Suydam chip catalog of 1880. See p. 402 of Seymour's book. Although it may have been offered to appeal to Masons, I suspect it was for home play. On the same page are designs of 3 chain links (IOOF?) a beehive (Mormon?) and a couple giving a secret handshake (recognize this, Chuck?).

Back to the original chip, the letters K.S.H.T.W. 2.2.T. should mean something to a Mason if that's what it was designed for. Dale just calls the design "Keystone".

I don't have the chip and would like to trade for one if someone has extras.

DonL