Concertina Reed Production
The Crabb Method

Reproduction of this article only with the permission of the Author

Introduction

Crabb's were a small producer of Concertinas in comparison to Wheatstone or Lachenal. Working in their own right from 1860 - 1989 very much as a Cottage Industry, the Crabb firm did not have the financial wherewithal to provide the facilities, production techniques or employment opportunities of the larger firms. To this end, production was very labour intensive and only possible by the large amount of hours put in by members of the family to be able to continue in business. Reed production was always a slow and laborious task to attain an acceptable quality and Crabb's basic method of reed making did not change during the life of the company. The finishing of the reeds was always left to the senior member of the family, having the most experience and practice in this highly skilled part of concertina making. The other member/s of the family would concentrate on the production of the reed parts and the fabrication of the rest of the instrument. Opportunity to perfect reed finishing skills was taken as time permitted and overseen by the elder Crabb until the time came for the next in line to take on this responsibility.

Reed Making

The following Crabb method of reed making is not intended as an instruction on how to do it but an insight into the process therefore dimensions etc. have been kept to a minimum to avoid confusion.

Reed Components:-

• Reed Blank - The basic reed frame shape, stamped from appropriate thickness sheet Brass or Half Hard Aluminium in a range of sizes.
• Reed Frame - The reed blank with the slot stamped.
• Reed Frame Block and screws - The securing assembly for the reed tongue.
• Reed Tongue - The steel strip secured to the reed frame which vibrates at a designed frequency when air passes though the reed and interrupts that air flow causing a sound to be heard by the human ear.

A concertina reed tongue of given length may be 'tuned' to cover a range of frequencies and so the range of an instrument and number of studs (buttons) will determine the number and sizes of reeds to be made for that instrument. Note. Because of the cost, Crabb made all their own press tools and used fewer reed sizes than Wheatstone or Lachenal. Example- Lachenal 48 Treble English concertina could contain 17 sizes of reed frame compared to 7 sizes used by Crabb for the same range.

The Reed Frame   With the sizes and number of reeds established, a large hand operated press was tooled up to produce the reed blanks in the sizes required, a pair of tools for each size. The press was then set up to rough stamp appropriate slots in the respective blanks. Again two more pairs of tools for each slot. The reed frames were then flattened under the press to remove any distortion caused by the stamping processes. The reed frame slots were then trued parallel and square by filing, a draft being formed towards the back or underside of the reed frame. ( Because this was done by hand and eye, the width of the individual slots in each size could vary slightly). The retaining slopes were then filed on the sides of the reed frames. The holes for the reed frame block screws were next drilled and threaded, fabricated jigs were used to correctly position these holes. The reed frames upper surface was then filed flat to produce a sharp edge to the slot and the intended note value stamped on the tip in front of the slot.

The Reed Frame Block   The blocks were made from brass or aluminium strip. Clearance holes for the screws were punched or drilled in the strip, the hole locations conforming to the tapped holes in the reed frames. The strip was then chopped into blocks using a punch and die in a fly press and loosely fitted to the completed reed frames with the screws. In the early days the screws were made on site, later they were bought in.

Reed Tongues   From circa 1860 onwards, reed tongues were made from spring steel, 'Brass' being used if requested or to replace broken/damaged reeds in existing instruments. The spring steel used in Crabb instruments came in large diameter (24 inches/600 mm) rolls of about 50 -100 feet (15 - 30 metres ) in length by 4 inches (100 mm) in width. This meant that as the metal was cut from the centre of the roll it would lay flat without the need of flattening. The steel thickness was selected by knowledge of the requirement for the ranges the reeds had to be tuned to, in general thicker materials were chosen for the lower notes and thinner materials for the high notes. Usually to enable selection of suitable steels, samples would be obtained from the supplier and trial reeds made before purchase. Spring steel appears to have a grain and this runs the length of the bought roll. This grain should run the length of the reed tongue and so strips would be sheared from across the roll, the width of these strips being 1.5 times the length of the slots for which the tongues were being made. This would allow a 'tail' for holding whilst processing, positioning and clamping of the tongue to the reed frame. The excess tail would be removed later. The strips would be fed into a shear fitted to a fly press. The shear could be adjusted to produce tongue strips just slightly wider than the reed frame slots for which they were intended.

Fitting   The tongue strips were then matched to their respective reed frames and filed along each edge and tip so that they would pass through the reed slot with absolute minimum side clearance. It was very important that the underside edges of the tongue were left clean, sharp and free of burrs. When this operation was completed, the tongues were individually 'voiced'.

Voicing is the process where the top surface of the tongue was contoured by filing to allow proper flexing of the tongue and to roughly 'tune' it to vibrate at the intended note frequency. To facilitate voicing, the partially processed reed tongue was temporarily clamped to its reed frame and a light line scribed across the tongues upper face where it emerged from the block. The tongue was then removed from the reed frame and clamped in a hand-vice, by the extended tail, up to the scribed mark. The exposed part of the tongue was then held on a suitable block arranged at right angles to the maker and the top surface filed to meet the aforesaid conditions. (The file would be held at right angles to the tongue but would be moved at 45 degrees diagonally across the tongue). It was most important that the tongue be filed equally across its whole width to avoid distortion when vibrating. Occasionally, the tongue would be held to the ear and flicked or 'pinged' to ascertain the nearness of the note produced to that required. (A master reed would be sounded in a tuning bellows for reference).

Assembly   When the maker was satisfied that the requirements had been met, the tongue was finally fitted to its reed frame, positioned centrally over the reed slot and securely clamped in place by tightening the block screws. Any protrusion of the screws from the underside of the frame was removed with a file. The reed would now be sounded in the tuning bellows and any adjustments made to ensure its correct operation. Fine tuning would be done on final assembly of the completed instrument. If all was acceptable the extended tail would then be snapped off. When all the reeds in a set were at this stage, the reed pans of the instrument would be processed to receive them.

Note.   To reduce the number of tool changes, all stamping and press operations were done on the same occasion. Usually enough reed frames were stamped/pressed in each size to cover the requirements of at least one years worth of instrument orders. A 'set' would then be selected and the filing and finishing processes done during the making of each order. A set of reeds could range from 16 for an 8 key English to 162 for an 81 key McCann Duet.

Warning Note   Rolls of spring steel in long length as described in the text, were supplied, bound around the circumference with a continuous welded steel band and contained in a stout wooden box. Because the spring steel was coiled from flat and not formed as a roll, there was an immense amount of energy stored in the roll. On no account was the roll removed from its box or the retaining steel band cut. The safest procedure was to carefully remove one face of the box and shear the metal from the inner end of the roll using hand shears, and suitable personal protective equipment. The box face was replaced when the required amount of material had been removed.   End