The drones, as detailed in the accompanying plans, are based on the design of the sets by Robert Reid and his son James. The Reids were responsible for adding the large amount of metalwork to the drones that add so much to the beauty of the pipes.
There is, in each drone, some 18 individual parts, not counting the wrapping and the reed. To avoid any confusion I will describe the construction of the large D drone and any references to dimensions will apply only to that drone. These descriptive notes should be read with the drawings to hand
It is best to start by producing all of the metal parts.
This is often made from imitation ivory but I have found that this can be rather brittle and I have see a lot of sets with this bead broken so I recommend the use of freecutting brass rod which will produce a pleasing result and is stronger in use.
It is important that the bore is smooth and parallel as any roughness will wear the cork lapping and make the bead leaky. I centre drill with a No 2 Slocomb centre followed by a pilot hole of 3mm diameter. The 9mm drill used to drill the bore to final size should be "backed off" this is done by carefully stoning the cutting edges until a small flat is apparent, this will stop the drill from "grabbing" and give a better finish to the hole. The external shaping of the bead is produced using a parting tool for the straight turning and either formtools or handtools for the decoration. The slot for the 1mm pin can be cut with a Junior hacksaw or a metal piercing saw but, if a milling fixture is available a better job is achieved by using a 1mm "slitting" saw.
These four tubes are gripped gently in the lathe chuck, supported with the tailstock and the decorative bands turned using a round nosed tool and a pointed tool ( I use an old screw cutting tool ), when the turning is finished use a piece of 600 grade emery paper to remove any burrs or blemishes and part off the tube ( remove the tailstock before parting off ). The cross holes in the tuning bead and the sliding part top tube are drilled in a pillar drill with the part held in a vice ( it is important when drilling holes in thin metal to guard against the drill grabbing and causing injury ).
A piece of brass rod 2mm diameter, threaded m2 for a distance of 4mm at one end.
2 pieces made by turning down a 4mm dia. brass rod, drilling a 2mm hole in the centre and parting off 2 lengths of about 1.5mm.
A decorative end piece, turned to shape and tapped M2 to screw onto the rod. The shape of this piece is a matter of personal preference most makers using a simple ball of metal or imitation ivory. The shape shown in these plans I have found much easier to get hold of. I make mine from Brass as I have found that the imitation ivory is rather brittle and this piece is quite vulnerable.
The two small rings are pushed onto the 2mm rod at the opposite end from the thread and soft soldered in position as shown. I have recently taken to using Loctite to fix these rings and haven't had a failure yet. The area between them can be roughed with a needle file up to help the thread wrapping to grip the shaft.
The imitation ivory mounts can be turned using either form tools or hand tools. care must be taken to avoid cutting too fast as some of the ivory substitutes are prone to chipping or even shattering. I use Vigopas P71A. If hand tools are used to turn these parts great care must be taken to avoid digging in as the material will shatter in a most spectacular way. Take care not to turn the base of the end cap too thin as the pressure of the wrapping can split it. The imitation ivory should be polished with polishing compound such as "T cut" or "Brasso" used on a clean rag. Take care not to burn the surface by applying too much pressure.
The wood for the drones is prepared in the same way as described for the chanter, first drilling the bore then setting up between centres and turning to the correct diameter.
Grip the blank in a three jaw chuck and turn the decorative bands on both the standing part and the sliding part. The decoration shown on the standing part differs from the Reid tradition in that it stands on, rather than being cut into the surface in the same way as the tube decoration. This decoration does have a historical precedent however, in the work of John Dunn. The remainder of the turning on the standing part is simple straight turning using a "knife tool". The fit between the tubes and the wood should be an easy sliding fit. Any tighter and there will not be room for the glue and if too loose it will be hard to fix them securely.
The grooves for the wrapping can be cut using a single point tool the same as the tube decoration I however have found that a very professional looking job can be done by using a "thread chaser with a pitch between 0.4 and 0.8mm. Mine is a 0.5mm pitch example, a legacy of my apprentice days, but they can be obtained from one of the tool suppliers.
The turning of the sliding part is similar to the standing part except for the socket. This is a very important part and must be both smooth and parallel. It is possible to drill this using a normal twist drill, but it does take extreme care to avoid inaccuracies. I always bore mine using a single point boring tool clamped in the tool holder on the top slide and advance it using the saddle driven, either by the fine feed or very carefully by hand, finishing off with several passes at the final setting to work off the spring in the tool.
The order of machining is more critical on the sliding part. I start with the blank turned to the outside size and with the decorative band finished. next I bore the socket to finished size, as described above. The blank is then mounted in the chuck with the tailstock centre located in large bore and the outside of the tenon turned down to accept the bottom tube. Remove from the chuck reverse and grip in the chuck on this diameter taking care not to grip too tight, support the top with the tailstock and, using the curved tool finish the 10.5mm diameter blending it in with the decorative band. The remainder of the turning can now be completed using the knife tool and a small parting tool.
The cork lining is prepared from 1.6mm (1/16") surgical cork. this is cut cork rather than the reconstituted cork and I think it makes a better job. Cut it into a strip 0.5mm narrower than the width of the recess. The cork will bend round more easily if it is rolled thinner using a 75mm diameter roller (bottle)this also has the effect of spreading the strip wider hence the need to cut it narrower than the recess. Cut the strip to a length that will allow the ends to just butt together when wrapped round the recess. I always glue with a water soluble glue as it is likely that some future maker will need to replace the cork. I have also found that non soluble glue soaked into the pores makes the cork prone to taking a set from the thread wrapping used to hold it in place whilst the glue dries. The cork is held in place by wrapping thin string around it for the full length of its fitting. It shouldn't be too tight - just tight enough to hold it firmly in place. When the glue is dry the wrapping is removed and the piece set on one side to allow the cork to recover from the pressure of the thread (about 24 hours should suffice). The work is then returned to the lathe and the cork sanded until the tuning bead is an easy fit with no looseness or gap. In order to ensure that the cork is reduced evenly it is best to glue the sandpaper to a flat strip of wood which is used in the same way as a file. Once the cork is finished to size the hole into the bore can be opened with a sharp scalpel - one reason why I have the two holes in line is that it makes it much easier to find the hole under the wrapping.
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