Screw-On Rubber Head Mallet: Rubber Members on Flanged Ferrules, Cupped and Cushioned on Steel Studs (Pemmerl, 1950)

"The frictional and cushioning washers 16 and 23, as interposed between the respective percussion members 14 and 17 and the mallet head 10, serve the two-fold purpose of setting up a strong frictional resistance against tendency of said percussion members to accidentally loosen or turn off the coupling studs 13 when the mallet is in use, while at the same time said washers act as impact shock absorbing means."

From 35 mm steel round bar turn a head 90 mm long between its end faces, and at each end a stud 13 12 mm across and 20 mm long; cut an M12 thread on each with the die. Drill a 20 mm eye through the middle, square to the axis, in a V-block, for the handle.

For each member, saw an M12 coupling nut to 30 mm and lock a 24 mm washer on it 4 mm from each end with a nut and thread locker: the flanges 19 round the threaded bore 20. Turn two cups from 45 mm bar: a base 3 mm thick with a 13 mm hole, and a skirt 12 mm deep bored 40.5 mm to embrace the member's inner end.

Scribe and cut 4 mm rubber discs 40 mm across with the knife: for each member, seven holed to the ferrule (24 mm holes level with the two flanges and 22 mm round the nut, so the discs either side trap each flange's rim) and five solid discs for the striking face. Brush contact cement on both faces, let it go touch-dry, and build the member up over its ferrule, the ferrule's end flush with the member's inner end; press it in clamps overnight and trim it round.

Turn an ash handle 300 mm long, fit it in the eye with a glued wedge. Cut two 6 mm rubber washers 23, 40 mm across with 13 mm holes. On each stud put a rubber washer, then a cup, skirt outwards, then screw a member on until its end is in the cup and the washer is squeezed; it should take a firm twist to undo.

**Michael Pemmerl** of Chatham, New Jersey, US 2,518,059, dated 8 August 1950, filed 31 October 1947. He claimed a mallet head with a screw-threaded coupling stud at an end, "a percussion member made of relatively soft material such as lead, an internally screw-threaded ferrule made of hard metal imbedded in said percussion member, said ferrule having external annular flanges", "a perforate cupped reenforcing member", and "a perforate rubber washer of substantial thickness" between cup and head. His soft members were moulded, and he names rubber among their materials; ours are rubber discs bonded round the ferrule. He also shows hard metal and rawhide members. He gives no sizes; every size here is ours.