Turning Pegs for the Lute
|
It is surprising how early in the construction of a lute that the pegs are required. Having made the pegbox, it is sensible to drill the holes for the pegs in the pegbox before attaching the pegbox to the lute. Further, these holes should not be drilled until the size of the pegs is known. The pegs are needed now.
Of course, the pegs can be purchased. Early music publications have advertisements from professional peg makers. Purchased pegs may, or may not, need their taper altered by the pencil sharpener treatment described below. An acceptable taper for lute pegs is 1 in 30. Thus if a peg is 7mm in diameter at one point, it will be 2mm less in diameter (5mm) at a point 60 mm distant from the first point. This is a handy measurement for ascertaining the taper of a peg. Wood for pegs must be tough and stable. Rosewoods, box and ebony have often been used, but the hardness of these woods makes them unsuitable. Very hard pegs tend to loosen unexpectedly due to their inability to cope with temperature and humidity changes. Fruit-woods such as plum, pear, apple, cherry work well, as do English sycamore and most maples. The wood can be dyed black to simulate ebony. The pegs can be turned on a small, steady lathe and a Jacobs chuck is used to secure the work. Most of the work is cut rather than scraped on the lathe. If this is not comprehensible it is time to visit the library for books on wood turning. 'Cutting' on a lathe means that the cutting tool produces shavings. 'Scraping' abrades the wood and produces dust. Cutting will remove a lot of wood quickly and cleanly but requires some skill to produce accurate shapes. Scraping works slowly and blunts the tools, but is sometimes the only way to finish a shape. As is often the case with instrument making, the basic principles of turning will apply, but the turning must be adapted to conform to the small size and precision of the work. Blanks for pegs are about 15x20mm in cross section. The length can vary as some pegs are much shorter than others. Generally, 135mm is long, 120 medium and 100 short. Most of the pegs turned come from medium blanks. It is best to make about 50% more pegs than needed and select the best. In order to fit the blank into in the Jacobs chuck, the first 15mm of each blank is reduced to a cross section of 8x8mm, and rounded a little. The end with the reduced cross section will become the head of the peg.
 It may be helpful to turn a peg or two which are exactly twice as big as necessary - multiply every dimension by two! The peg is easy to turn and is a remarkable object. Turning is wonderfully satisfying but gets a little tricky when twenty identical objects are to be produced. A full size inside template of half the peg will help. So will having three sets of small calipers set to 16, 7.5, and 5.5mm. Start the turning by taking the blank down to 16mm cylinder. Mark the extremes of the head with a pencil on the spinning wood. Also mark where the head is widest. Then mark the 1.5mm to the collar and then 1mm further for the collar itself. This is also the point where the diameter of the shank will be turned to 7.5mm. Sixty millimetres away mark the point where the diameter will be 5.5mm. Later the 7.5mm and 5.5mm will each be reduced by about 0.5mm in the peg sharpener.
 Now turn the shank of the peg. This is the part of the peg which must be made accurately. Scoop out as much as possible with gouges then scrape. An old extra wide chisel makes an excellent flat scraping tool. Use the calipers to test that the shank tapers evenly from 7.5 to 5.5mm. Create the collar on the shank and finally turn the head. Make use of the lines already drawn on the head to indicate where no further wood is to be removed. Also check with the template. When satisfied, part the shank end and then the head. Do the latter carefully and avoid creating a pit in the top of the head. And then make nineteen more. The round turned heads of the pegs need to be shaped into flaps so that the pegs may be used to tune the strings. The flaps tend to split if they finish up quarter sawn so orient the wood the other way. Excess wood can be removed with a chisel or a disc sander, but do not clean them up any more than this for the moment as attention must first be given to finishing the shanks. A tapered reamer will now be needed, and and will be needed again after the lute acquires its finish. It needs to have the taper required, near to 1 in 30, and should not have flutes (the sharpened cutting grooves) all around the reamer. Three flutes covering less than half the tool is adequate. The more common reamers with flutes all around tend to make star shaped holes in wood. Buy, beg, or borrow, one of these reamers will be needed. The first job with the reamer is to make a device rather like a pencil sharpener. It shall be known as the peg sharpener and its purpose is to give the pegs the exact taper required. The blade used will determine the width of the peg sharpener and it is quite acceptable to have two; one for wider diameters and another for the smaller. The blade from a smoothing plane works very well but a wider blade is better. The peg sharpener will be made from a block of hardwood from 40 to 60mm wide and a hole needs to be reamed through it. This is hard on the reamer so reduce the stress on it by drilling holes of increasing diameters where the reamer is meant to work, as shown below.
 Plane away the top of the block down to the dotted line and the reamed hole will begin to appear. Affix a sharp straight plane blade to the edge of the slit. After some practice and adjustment it should be possible to shave down the pegs to the exact taper of the reamer. To put a nice finish on the pegs lightly sand the shanks and use a scraper and sandpaper to clean up the heads. Run them all under the tap for ten seconds and leave for a day. The wood will roughen as the grain is raised. Sand again to smooth the raised grain and rattle the lot of them in the hand to hear the sound they make. A small amount of varnish is needed to finish the heads. Dilute the varnish by fifty percent and dip the heads only. Shake off the excess, let dry, sand lightly and repeat twice. For the shanks, make a mixture of equal volumes of beeswax and pure turpentine in a glass jar. The mix will form a paste after a few days. Smear a light coating of the paste on the peg shanks and let it dry for a day before buffing with a cotton cloth. Again rattle them and listen. Now return to the pegbox. Knowing the size of the pegs allows the larger holes to be drilled to follow the pilot holes. Each peg requires two holes, the larger of which is the same size for every peg. For the pegs described above the size of the larger hole for each peg is 5.5mm . The smaller holes vary in size with the longer pegs at the wide end of the pegbox requiring the smallest holes. These holes range in size from 4 to 5mm . The holes can then be reamed out so that the pegs shanks protrude about 17mm. When finally fitted there will be about 12mm between the collar and the pegbox, but for now be generous with 17. Look carefully at the fit of the shanks. The fit at the wide end of the peg shank should be tight with the narrow end turning much more freely. Too much friction at the narrow end will allow the peg shank to twist and stick making their use as tuning machines inefficient. Cure any problems with judicious use of the peg sharpeners and sandpaper. Get all the pegs working well while protruding 17mm and then remove them. The final fitting of the pegs will come only after the lute has had a finish applied.
|