A Tour of the Reedpan

Note that there is much detail left out of this drawing, as well. For more detail, look at the photos which follow. In particular, only two reeds are shown in place. Also, you should realize that the other side of the reed pan, while it does not have the partitions and center doughnut, it does have alternate reeds for operation while the bellows are being pressed. The reeds which you can see here are those which sound while the end boxes are being drawn apart.

Also only minimally shown are the valve flaps, "leathers", or "skins", which seal the air passage for the reed which is currently not receiving the proper direction of air flow. They are better shown in the later closeup of the back side of the reed pan.

reedpan

Note how the holes in the valve board (to the right) align with the chambers in the reed pan.

Partial edge-view photo

Here, you see the photo of the side of the reedpan which faces the valve board. There is some discoloration on some of the brass reed carriers.

The chamber walls are visible as radial lines towards the thumb hole in the (approximate) center. One thing visible in these photos which is not normally visible when working on a reedpan is the joining of the chamber walls to the doughnut. (However, that area is somewhat out of the plane of best focus. -- The next photo will show that part to better advantage.) This particular instrument had an argument with a rainstorm, in which the recessed latch on the Anvil case (atypically facing up, thanks to the way things were stored in the pickup) acted as a funnel to guide water into the endbox of my Wheatstone Treble. This softened and damaged the valve pads, and dissolved the glue holding the (white) leather seals to the doughnut and the top edges of all the partitions. Thus, I had an opportunity to photograph it without the seals prior to making new ones. (I used some synthetic-fiber felt instead of leather as an experiment, and it seems to be working well so far.

jpg version -Size: 174871 Bytes

gif version of the above. Size: 678,026 bytes.

Note that the large version of this image is jpeg format, which saves size and download time, but which may not be viewable by all systems.

I would appreciate e-mail from those who cannot view it. If I get none, I will replace the other images with jpeg format as well. If I get a lot, I will change this image back to gif format. If I get just a few, I will put both formats, with the default being jpeg, and an alternate link to view the gif format, as in the above. You can see, by comparing the two sizes, that the jpeg format offers significant savings in download time. If everyone were using Netscape, I could simply eliminate the gif format entirely.

Thank You.

Photo of part of a reedpan.

Note the pins which are intended to keep the valve flaps from being swallowed through the valve holes.

You should also be able to see (at least in the enlarged version of the photo) the dovetailing which retains the reeds in their places.

The partitions are clearly visible in this photo. They are used to minimize the volume of the chamber to maximize the sound available from the reed.

You should also be able to make out the heel ends of the reed carriers for the other side, just visible under the edge.

Photo of the back of a reedpan.

Note the absence of the partitions which were evident on the other side.

Closeup photo of the back of a reedpan.

This image will give you more detail -- perhaps enough to see how the reeds are dovetailed into the wood of the reedpan, as well as the valve flaps (or skins, or leathers).

Also, you can see signs of tuning* on both reeds. The one on the left has been tuned down quite a ways (from Salvation Army pitch to modern, with a little overshoot, and then tuned back up to the target pitch. The one in the center has been tuned down only, with no overshoot. The partial one to the right also shows (to the extant that is visible) signs of tuning both down and up. The scale factor in the lower right-hand corner gives the scale for a 35mm slide. The image as presented (at least on my screen) is significantly larger, so please take that into account when estimating sizes.

* The tuning left the reed surface with a higher polish than the original ground surface present on the reeds. (The underside of a reed is usually still the blued steel of a hardened spring, but the top has typically been ground over the entire exposed surface in the process of producing a reed for a given pitch and responsiveness.) Given the angle of the reed, and the source of illumination (ring flash built into a "Medical Nikor" closeup lens), the tuned areas are reflecting un-illuminated parts of the room, so they show up as black, while the rougher surface of the original untuned areas scatters the light, and appears brighter. Under more normal illumination, the recently-tuned areas will appear brighter than the untouched surfaces.

Photo of two extremes of reed size.

Here, you see two reeds from a Wheatstone English system treble concertina. These are the extreme bass and treble reeds of this instrument. You can see some signs of relatively recent tuning in the area near the clamp strap on the smaller reed.

Note that the reeds vary greatly in dimensions, depending on the desired pitch of the reed, and other factors. The reed only sounds when air is flowing from the top (view in upper half of the drawing), which will tend to carry the reed tongue into the slot. The reed normally stands slightly clear of the slot, as shown in the side view on the bottom half of this drawing.

DoN.

Copyright Donald Nichols - June/July 1995