Keys for Penny-Chanters, temporary replacement keys for traditional chanters, and regulator keys.
Use medium thickness brass strip 1/4" wide; 1/16" thick perhaps.
Cut length of key. Leave enough for finger at end, flat. Make a 90 degree twist over short distance, from there through the location of the axis. Make another 90 degree twist for the pad end of the key.
Photos illustrate key after 3 minutes work, cut and bent to initial shape.
Bend pad-end down a few degrees at the twist, then back up parallel so that pad can contact the chanter hole squarely. Fix leather pad on underside of end with (super)glue.
Grind underside rear of vertical center axis section so that the finger end is clear to pivot downward. Additional filing or grinding of corners and shaft according to desire for appearance.
Drill hole through mount for pin, use rubber o-ring or Keenan style rubber band as spring. ;)