Thoughts and Insights on the Design of the Smallpipes
(updated 28/05/10)
First about me, as the background and experience of any maker will have a significant influence on the pipes he designs. I have worked as an engineering Designer for 45 years mainly designing machinery for the manufacture of products. One example is the design of part of the machine that makes round teabags. I also invented, designed and developed a new type of printing machine used to date code products like crisp bags. This background has left me with an approach to designing and making that is firmly anchored in the engineering tradition.
The design of the pipes presented here are influenced by the making of 2 famous makers from the past. The main outline of the design of the drones is from the work of James Reid and particularly from the set of his pipes that are illustrated in the second edition of The Northumbrian Bagpipes by Cocks & Bryan, now sadly out of print, but you should be able to borrow a copy from a library. The embossed decorative rings on the drone standing part are influenced by the unkeyed set made by John Dunn and illustrated in the same book.
James Reid was influential in adding a lot of metal decoration to the sets he made and I have heard it said that he was originally an umbrella maker which would explain the fine quality of his workmanship.
The main differences from the Reid design is in the tubes where I have chosen to use standard parallel drawn brass tube where James Reid has created tapered tubes by wrapping sheet around a mandrel and silver soldering the joint.
The information below is an attempt to gather together the considerations that influence the design of the traditional Northumbrian Smallpipes.
The pitch of the pipes
Traditionally the pipes didn't need to have an exact pitch as they are really a solo instrument but there's no reason to assume that pipes didn't begin with an exact and common pitch. I'd guess that Reid used his tuning fork like any other good woodwind maker. The natural pitch of Reid pipes is sharp of concert F and nearer F#, i.e the flat semitone below modern pitch which is commonly, if imprecisely, known as 'baroque pitch' or A = 415 Hz.
I know that there is a view that the "standard" pitch of the pipes should be fixed at 20cents sharp of concert F. This was brought about by a desire to bring other makers' pipes into the sharp pitch of the most prolific maker which in my view isn't a good reason for setting it as a standard. The history of woodwind design is littered with odd-pitched instruments which seemed to be a good idea at the time but have proved later to be a bad idea.
My personal opinion is that the pipes should be at concert pitch, that is concert F for standard pipes and concert G for G pipes. I do understand that there are often local pressures that dictate a different local standard pitch and, if you only ever play with other local pipers, then it would be sensible to have a set of pipes that is in tune with them. However, in these more modern times when there are increasing numbers of other "fixed" pitch instruments being played in ensemble with the smallpipes and the increasing use of electronic tuners has made concert pitch a universal standard, it would seem regressive to continue with a standard for the pipes that is in conflict with this. I always make my pipes to play at concert pitch. and the hole positions given in the drawings should achieve this. If it is required to make the pipes play at a sharper pitch I have found that it is simply a matter of choosing a reed that plays at the required pitch and tuning the pipes accordingly. I have been able to pull sharp pipes down to concert pitch and my own pipes up to the sharp pitch just by selecting the appropriate reed and doing a bit of retuning of the holes.
Playing pressure
When I first started making I was guided by Colin Ross to the use of a water manometer to setup the pipes and the recommended pressure was 15" water gauge (WG). This seems to be a good starting pressure for a new player. There are some well known players who have settled on a much lower pressure of 12"WG and they seem to find this an easy pressure to play at.
One consideration is that the lower the pressure, the more skill it takes to maintain it evenly.
I find that I am comfortable at a pressure of 16"WG and when I am in practice this can raise to 18"wg
The Drones
The layout of the holes in the drone stock for fitting the drone standing parts have been carefully designed such that each of the drone sliding parts can be moved through its normal tuning range without being impeded by conflict with an adjacent drone nor risking inadvertently moving and already tuned adjacent drone.
The outside diameter of the standing part mounts has been selected so that, when assembled, they don't conflict with the mounts of the adjacent drone i.e. no need of flats on the mounts.
All of the tuning beads are provided with a pin and slot system so that there is no searching for the holes to line them up. James Reid only did this on his large "G" drone but the benefit is sufficient to make the extra work worth the effort.
I use genuine sliced cork in sheets 1/16" thick to cut the strips for the tuning bead seal. It does take some care to select the part of the sheet that is free from defects. I know that other makers use reconstituted cork because of its more uniform structure but I have found the genuine item is more tolerant and works well.
The bore of the sliding part is a very important feature and needs to be both parallel and smooth in order to work well. I machine the bore in the wood of the drone and fit a thin tube over it and this works well for me. The bore does need to be machined using a single point boring tool as drilling will not produce the accuracy required. Other makers have simplified this joint by using thicker wall tube and using the inner bore of the tube as the sliding joint. This also work well but does demand a good firm joint between the wood of the drone and the tube. I have had to repair a number of this design where the tube has come loose and is leaking sufficiently to spoil the sound of the drone.
The drone sliding part cap should be held firmly in place by the wrapping of thread around the tenon. On no account should this be glued on as future repairs and maintenance will be compromised.
The bores of the drones as shown in the drawings for the standard "F" set are optimised for cane reeds. I have found that the composite reed will sound better if a slightly smaller bore is used - about 0.2mm off of the diameter of the 2 small drones and about 0.4 off of the bore of the bigger drones.
When wrapping the drone standing parts to fit into the drone stock don't be tempted to make the fit too tight and it will make removal difficult. Aim for a firm slide in. The fit between the siding part and the standing part should be carefully set so that it can be moved easily but doesn't move accidentally in use. The fit of the wrapping of the end piston should be lighter still so that it can be opened without disturbing the tuning of the drone.
The knob on the valve at the top of the drone sliding part has only 2 functions. a) to stop the valve falling into the drone and b) to make it easy to open the valve. I personally have great difficulty opening the ones that are fitted with a ball (no fingernails) and I have seen others struggling with this style of knob. My personal favourite is the one drawn here as I have found that it is really easy to open. There are other designs that will work as well and I have seen an acorn shaped knob that also worked well.
The Chanter
The bore of the chanter is the most important feature from a tone point of view. A really smooth, parallel bore of Ø4.3 (11/64") gives the best sound and pitch for the standard "F" chanter. One of the reasons that woods like blackwood are used is that they will take on a very fine finish. Other, more open grained, woods like rosewood can be improved by a coating of shellac (French polish) in the bore.
When drilling the tone holes I take great care not to mark the back of the bore by drilling too deep as this also effects both the quality of tone and the tuning of the note. I have had to re-reed chanters that have been troublesome and found that they had a divot at the back of the bore under every tone hole. Filling them in and re reaming ( a long and tiresome job) made fitting the reed and retuning the chanter much easier.
The small outside diameter of the chanter has an effect on the brightness of the notes of the chanter. It also has an effect on the amount of wood available for tuning a note. As the bottom notes of the chanter need more undercutting for a given increase in pitch I have chosen to make the bottom of the chanter a larger diameter than the top of the chanter as this has little effect on the brightness and make tuning much easier. It does make the turning more demanding and if desired it could be parallel and about Ø11mm. I have made chanters thinner - my first chanter was a copy of the one illustrated in the Cocks & Bryan book and I took the measurement from the thinnest view (all the illustrations have different diameters drawn varying from Ø10.0 to Ø12 and there are no dimensions to guide the maker) I made my chanter Ø10.3 and parallel. It is a good sounding chanter playing sharp of concert F.
The linings that I use are intended to make the keys work well rather than to add strength to the wood of the chanter. I use quite thin brass for these. The single key linings are from 0.25mm thick brass which, when fitted into a 2.5mm wide slot gives a 2mm thick key and this seems to be ideal. For the double keys I use 0.33mm thick brass and when fitted into a 5mm wide slot gives 2 slots 2mm wide.
I use a parallel Ø1mm pin for the key pivot and am careful to make this a good fit in the drilled hole so that it doesn't come out unless taken out. Some makers use a tapered pin put into a tapered hole but I prefer parallel as I don't have to worry which way the pin comes out or goes in and the pin is not unique to a hole.
Another problem with taper pins is that if the do move and come loose they get very loose very quickly and often will fall out. Also the poor unsuspecting pipemaker who needs to remove a key must guess correctly the direction of the taper or risk splitting the key block.
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The keys
I make my keys from brass rod as described in the key making section. Some makers use cast keys but I haven't seen any that look as nice as the key design I learnt from Colin Ross. I have made keys from sheet brass but they tend to be rather bendy in use.
Springing is very important. I have measured a lot of keys as part of the School Pipes design exercise and it seems that the keys that feel the best, start to open when a force of between 50 and 60grams is applied to the touch piece and the force stays as constant as possible as the key opens raising to no more than 100gram when fully open. To achieve this it is better to have a strong spring as close to the pivot as practicable. this will make the effective spring rate(the change in force divided by the distance moved) lower than a weaker spring further from the pivot. See here for collected data.
Another consideration when designing the spring is that these leaf springs are rather highly stressed and prone to breaking from fatigue. To reduce this I take great care to polish all the surfaces of the spring making sure that there are no scratches running across the surface. The choice of a stronger spring moving a shorter distance as mentioned above will also reduce the fatigue stress on the spring.
Whilst designing the School Pipes I did some experimenting with a much simpler and more robust type of springing. I worked out how to fit a coil spring close to the pivot and, by putting the dimensional data and the spring rate for a number of different springs into a spread sheet, I was able to optimise the design to get a much nicer feel to the key movement. I made a prototype 5 key set and tested the concept. here is a picture of the way I fitted the spring. I have seen a number of springing methods used and it seems that whenever a coil spring is mentioned it is dismissed as "tried that and it was hopeless" but whenever I delve further it seems that the spring was put under the touch end of the key where it is bound to fail. I will probably do some further experiements to see if this concept can be easily applied to the normal smallpipes without compromising the functionality, looks or feel.
The Bag
I have sewn my own bags when I first started but later I had them sewn by a leatherworking friend. I would now purchase the bags in the small quantities that I need. I have used bags made from a Gortex type material originally used for the Highland pipes and obtained from Ross Pipes in Australia. They were used for the School Pipes project and cost about £8 each (in quantities of 200)
Bag Size. I use a bag that is on the large side. similar to the bags used by David Burleigh. One of the best bags I have used was obtained from Ray Sloan (I think) and it seemed to be made from a rather nice leather sealed with a latex material painted on the inside probably before the bag was sewn up. I think that the latex was coated with something like French chalk to take out any stickiness. This bag was very airtight but expensive (about £80 in 2003)
The Bellows
My first set of bellows was made from the drawings in the Cocks and Bryan book and proved to be a bit small and took a lot of pumping to fill a bag. Looking at the design it became clear that there were 3 features that were limiting the pumping.
The hole in the outlet pipe was too small thus limiting the easy passage of air
The leather of the bellows was too soft thus limiting the volume of air that could be sucked into the bellows.
The plan shape of the plates was too small thus further limiting the volume of air passed with each stroke.
To solve these problems I made the following changes:-
increased the outlet hole from Ø3/8" to Ø1/2".
Used a thicker and stiffer leather - 2mm thick panel hide.
Smoothed out the shape of the bellows to increase the surface area.
Concert G Sets
The major difficulty for most people playing a concert G chanter is that the holes are too close together in the top hand. I have rather fat fingers and this is a significant problem for me. I have tackled this problem in 2 different ways. I made 2 long scale 7 keyed G chanters some years ago These were really f# chanters fitted with a reed that pushed them even sharper. Reeding these chanters was very difficult and I wrecked many good reeds before finding one that worked and it was this chanter that Joe Hutton played for many years with the Shepherds.
The second way I tried to make a chanter that I could play, was to spread out the top holes by drilling at an angle, (I will do a drawing of this in the future). This method proved successful and I was able to play this chanter. This chanter is now in the hands of Alice Burn
Another problem with concert G pipes is that they can be too loud and rather shrill sounding. This can often be cured by using a narrow reed (10mm instead of 11mm).
The concert G sets are often set to play at a higher pressure than the normal "F" sets. This is to help push the chanter up to concert pitch. With a properly set reed it should be possible to get the set playing at concert pitch at a more normal pressure.
I usually use composite drone reeds with G sets as this seems to work better. The set that Joe Hutton played had composite reeds and sounded well enough to satisfy Joe's demanding ear.
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Concert Pitch "D" Chanter
I have made only 1 "D" chanter and that worked well once I had repositioned a couple of holes. I based my measurements on a copy I took of Colin Ross's hole gauge and I could have made a mistake in the bottom "A" hole that I had to move. The top "e" hole however was in the correct place according to the measurements I had taken but I had to move it down from 31.7mm from the shoulder to 35mm from the shoulder in order to get it in tune. I think that if I was making one now I would move the top "e" to 34mm from the shoulder but the 35mm dimension does work.
5 Drone Sets
I have made a couple of 5 drone sets. The most common is to have an "A" drone as the extra as this gives the possibility of having a drone harmony of "aAA" giving a sound that works well with the Scottish tunes. A further benefit is that it is not necessary to have a second bead on the G drone to get a "B" drone used when playing in the key of E or Em. I personally don't like fitting a second bead to a drone as I feel that it clutters up the drone and looks wrong.
If you want to add the 5th drone you should use the same 5 drone stock as drawn for the "G" set and instead of using the "A" drone drawing of the "G" set use the "G" drone drawing of that set together with its metalwork.
For one of the people I made a set for requested that I did 5 drones but with a B/C drone as the extra one as this would allow tunes in "C" to be played with a "CG" drone harmony. As this was an "F" set I used the dimensions as given for the "A" drone of the concert pitch "G" set and this work well.
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