Kensington Concertina Construction

Kensington concertinas are very similar to traditionally constructed concertinas made by Wheatstone, Jeffries and Crabb. They have reeds mounted in individual shoes or frames that are mounted directly to the wood surface of the reed pan. The reeds themselves are steel in bronze shoes, and the reed shoes are specially made to provide a wide dynamic range at low pressures. Some concertina makers use accordion reeds, which are designed around different needs. Their relative stiffness and the mounting method generate a different tone quality richer in upper harmonics and poorer in the fundamental tone than the traditional concertina reeds.

Traditional reeds are made with tapered dovetailed sides that slide snugly into special slots cut for them. This system has worked well for a hundred years or more, but has problems when the instrument lives in a climate with wide swings in humidity from summer to winter. Being held by their sides, the shoes are alternately pinched and released by the shrinking and expanding wood. Eventually the reed shoes become permanently loose, and need shimming of one sort or another to work properly. If you live in England or Ireland with their consistent high humidity levels, this is rarely an issue, but much of the U.S. changes drastically in humidity over the seasons, making this problem common.

In Kensington Concertinas, I changed the mounting method to hold the shoe at its ends, in a direction that the wood moves very little. In all other respects, the reeds are the same as the traditional long scale reeds.

Traditional concertina reed pans also can develop leaks around the ends of the chamber walls, and have poor contact with the face of the action pan that rests on top of it. This can cause some reeds to sound dull while others are clear. Kensington concertina reed pans are made from one piece of quarter sawn wood with an integral wall at the chamber ends. The reed pans only have one sealing surface instead of two, and are clamped both at the center and outer rim to the action pan, insuring solid contact everywhere, and reeds that sound consistently clear over the entire reed pan.

The action of the best traditional concertinas used a lever riveted to a post, providing smooth travel and good alignment of the pad over its hole. Kensington Concertinas use a special fork pivot that provides stability for the lever, yet allows easy removal for re-padding or adjustments. It uses a downward pulling spring, instead of the normal upward pressing one, is automatically wear compensating and counters the tendency of the traditional springs to pull the lever posts out of the action pan over the years.

The buttons are made of Delrin for its low friction surface, with special teflon impregnated Delrin guide bushings in the action pan for a smooth action that is tolerant of the misalignment of a button that is not pressed straight down. Button pressure is set at between 50 and 60 grams. To a novice, very light button pressure is often equated with a feeling of speed, but experienced players find out that it is not the speed you can press a button down that counts, but the speed you can come off the button that counts for quick crisp playing. Button pressure of 50 to 60 grams allows light enough pressure to be comfortable to play, yet enough return pressure to assist in getting your fingers up quickly.

The end frames are made of a composite called Dymond Wood that is very dense and hard, is almost completely waterproof, and can take a high polish without need for additional finish. The end plates are Nickel Silver, a copper nickel alloy, that has been used in metal ended instruments for over a hundred years, is easily cleaned and wears well.

Bellows are traditional leather over card stock. I use goat skin leather for its toughness and ability to take constant flexing without tearing or cracking. After an initial break in period, they are both flexible and firm, allowing fast response to direction change yet resisting sideways flex that renders the quick motion of the bellows useless.