At 08:19 AM 11/2/99 -0700, you wrote: >Hello all: > >Although metal working is not my forte, I do use metal (brass) to make the >gnomons for my stone sundials. I have found that the common Dremmel >moto-tool when fitted with a Dremmel 1.5" black composite cutoff disk and >arbor, will easily cut metal. These cutoff disks will be found in the >Dremmel department of your local hardware store. They can be used to make >straight cuts and also are suitable for some types of engraving. > >If you buy a sheet of metal (brass, copper, aluminum, or steel), you can >easily make your own gnomons. I use 14 guage (1/16" thick) sheets, but this >method will cut even thicker pieces. I suggest that you use the perfectly >straight foundry-cut edge of the sheet as the style side of the gnomon. >First draw the lines to be cut with a fine point "Sharpee" pen or glue a >paper drawing of the desired cuts onto the metal with water soluble white >glue. After cutting the other sides, use sandpaper with a block of wood to >smooth the sides that you have cut with your Dremmel. Holes for attaching >the gnomon to your dial plate can then be drilled through the metal with a >hand-held drill with metal bits. (Before drilling, make a little indentation >in the metal with the point of a nail and hammer to serve as a guide for the >bit so that it doesn't wander). > >Besides cutting metal sheets to make traditional triangular gnomons, your >Dremmel can also cut rods for vertical or perpendicular gnomons. > >I Hope this simple technique will be of use to some of you. > >John Carmichael >925 E. Foothills Dr. >Tucson Az 85718 >USA >tel: 520-696-1709 >website: http://www.azstarnet.com/~pappas > >
Few questions and points: 1) How do you attach a 1/16" thick gnomon vertically to a dial plate? Presumably you must bend the gnomon at the base somehow first. 2) I use 1/8" brass for both the dial plate and the gnomon. I used to drill 1/16" holes into the bottom of the gnomon (there is just enough space) and corresponding holes in the dial plate. Then I used 1/16" brass brazing rods cut to small lengths as pins to hold the whole thing together. Worked surprisingly well. More recently I made somewhat fancier gnomon with bits of 1/8" brass and soldered it to a 1/8" base with holes in it to screw the whole assembly to the dial plate. On the whole, I was more pleased with the latter. 3) I like to do the final shaping and smoothing of the gnomon on a belt sander using 120 grit paper (the finest I have been able to get locally - I have seen knife-making supply shops advertise finer grit in the US). The straight edges are great and one can get he gnomon angles just right. I then buff away the 120 grit marks using a felt wheel and an aggressive buffing compound on my bench ginder. 4) For marking out holes for drill bits I suggest using a proper marker punch - nails tend to have rather unpredictably irregular points. Mike Koblic, Quesnel BC
