Steve's Corner - Hammer Tips
When the Rhodes Suitcase pianos were first introduced in 1965, they had hammers similar to an acoustic piano. As each string (or set) on an acoustic piano is slightly different, the hammer is shaped and sized for that string or note: so were the hammers on the early Rhodes. Shaping (voicing) each hammer was very time-consuming and costly. Around 1970, Rhodes changed to a neoprene hammer tip mounted (glued) on a wooden (maple) head. Later the hammer became one molded plastic piece, instead of one that was a plastic shank with a wood head. Originally the glue was weather stripping adhesive (3M 8001), which was normally used on car doors. Later we changed to super glue (cyanoacrylate).
Because each tine is slightly different in length, theoretically, different tip hardness should be required as it was in the previous felt hammers. This was not practical, so Rhodes settled on 5 hardness gradations across the 73 keys (and later, the 88). They were as follows:
- 00 - 23 = 30 shore
- 24 - 33 = 50 shore
- 34 - 43 = 70 shore
- 44 - 57 = 90 shore
- 58 - 81 = Maple with 3 layers of shrink tubing
"Shore" is a rubber hardness or penetration measurement.
The original neoprene tips had dye added to the rubber to identify the hardness. Later it was found that the dye caused the neoprene to deteriorate quickly, so the tips were painted instead:
- 30 shore = Black
- 50 shore = Red
- 70 shore = Yellow
- 90 shore = Black
The 30 shore (very soft) and 90 shore (very hard) were easy to tell apart, so no color was needed.
The tips changed in size and shape over the course of the piano's production. Originally, they were 3/8" square. Then they had slightly different heights, and later, they changed shape. The shape change was due to the fact that only one edge of the tip comes in contact with the tine: the tip shape was changed from a rectangle to a somewhat triangular shape. This latest version works as a replacement for the early versions.
The gradation assignment was a compromise: too soft of a tip for a particular note and the sound has a "thunk" to it; too hard a tip and the sound has a "clank" instead. But some people liked more thunks or clanks, especially clanks, because along with the clank came stronger upper harmonics. So the practice of increasing the ranges of the harder hammer tips began. It was fairly common to convert the last ten soft blacks to red, the ten reds to yellows, and the last ten yellows to hard blacks. This would give a piano a very bright and clanky sound, and the clank could be minimized in the mixing process.
Occasionally the wood tips were extended down a few notes as well. The wood tips could get clanky quickly. They were made using a strip of "hard rock maple" (as we called it), which was shaped like a piece of molding. This strip had three layers of shrink tubing applied, then the strip was cut into the appropriate tip widths. The wood tips dented easily, so using any other type of softer wood (such as pine) would result in a very quick deterioration and the need for replacement.
The tips are rubber, so after a period of time they can harden slightly due to oxidation. Also, after repeated strikes of the tips against the tines, especially over a period of years, the tips will develop a hard spot were the tip contacts the tine. The hard black tips are especially prone to spot-hardening. Shaving the tip with an exacto knife just under the hard spot will restore the softer strike edge (if this is desired). Because shaving changes the tip height, it is only recommended to do it twice.
To replace a tip, just pull it off with pliers, then use an exacto knife to scrape off the remaining rubber and glue residue. Apply super glue to the hammer and attach the new tip.