<HTML> <TT>Newton,</TT><TT></TT> <TT>I've had great success with the large size of steel "music wire" sold at the hobby shops (right next to that brass wire of yours); it hardens nicely, so now I've got a great set of miniature chisels (0.019?!!). A more square version of your corner chisel could be fashioned kind of easily out of this.</TT><TT></TT> <TT>Ken,</TT><TT></TT> <TT>The x/y vice technique would work, actually simpler and with less set-up between mortises with a long (uncut) button moulding than for cleaning out existing mortises. I'm not so sure it could work with blanks glued onto the individual keysticks, though.</TT><TT></TT> <TT>Anyhow, it gave me an idea at least to improve my current technique: use an end-mill to cut a mortise in a rectangular piece of plexiglass parallel to the long sides, off center lengthwise so that it can be flipped alternately to cut naturals and sharps. Square up the ends of the mortise with a file.</TT><TT></TT> <TT>To use it, mark the long button moulding for the center rail pattern  and drill along the center lines. Then use a machinist square from the edge of the moulding to position the plexiglass jig over the holes, clamp it in place and use the two sized chisels to finish the mortise, or alternately, using Newton's drill-press corner chisel.</TT><TT></TT> <TT>Not cutting the slots for bushing from underneath certainly can't harm the buttons, and should add some stiffness to the keys.</TT><TT></TT> <TT>Clark</TT><TT></TT> <TT>ps - Ken, what'd you do with all those replaced oblong Knabe balance pins?</TT></HTML>