Probably the most often used tool in the field of handmade jewelry is the is tool consists of a saw frame and a fine-toothed blade.
Jeweler’s Saw – The Frame
The frame resembles somewhat a fretsaw or coping saw. It is made of a good grade steel, tempered properly so as to have some degree of “spring” to it. A good quality frame should be used. These saw frames vary in depth, that is, the distance from the saw blade to the back of the fame. Depths vary from about 2¼” to 12”. A 3” frame is a good size for jewelry. For work on bracelets made of 6” to 8” strip, a 4” frame may be desirable. The distance between the two clamps on the frame is variable, making it possib1e to utilize blades that have been made shorter through breakage. The standard blade length is 5”. The clamps on the frame are made tight by thumbscrews and it should not be necessary to use pliers on them.
The Saw Blades
Jeweler’s saw blades are available in various sizes. The size refers to, though it does not literally indicate, the number and size of the teeth on the blade. The length is always 5”. Sizes used by jewelers run from about No. 4 is the coarsest, 8/0. No. 4 is the coarsest, 8/0 the finest, numbers running 4,3,2,1,0, 2/0, 3/0, etc.
These blades should be of fine, tempered steel. The two end portions without teeth are tempered differently from the cutting portion. The end portions are somewhat softer, in order to withstand the strain and flexing stress at the clasps. The middle cutting portion is tempered very hard, so as to cut metal, and is rather brittle. When the end portions of the blade break, many users shorten the frame and continue to use the remaining saw blade. This may be done, but the frequent breakage which then occurs is due to the breaking of the brittle cutting portion of the blade which is now in the clamp.
The choice of blade size depends upon the thickness of the metal to be cut, and to some extent on the intricacy of the design. For No. 18 gauge metal, a No. 1 blade will suffice. This is probably the most commonly used blade size. Actually, although this practice is not assiduously followed.
Using the Saw
To mount the blade, loosen the thumbscrews on the clamps one or two turns. The frame should be set so that the distance from the center of one thumbscrew to the center of the other is about equal to the blade length. The frame is then held, and one end of the saw blade is clamped in the upper clamp. The blade should be held so that the teeth point outward from the frame and toward the handle. This permits the teeth to do their cutting on the down, or pull, stroke. When one end of the blade is tight, lean the body forward against the handle so as to bring the two clamps on the frame toward each other. The lower end of the blade is quickly set into its clamp, which is made tight, and body pressure is released. Plucking the blade lightly with the finger should produce a clear musical tone if the job has been properly done.
If a blade persistently slips out of the jaws of the clamp, do not condemn the saw frame until you have opened the clamp entirely and inspected the inner surfaces. A piece of saw blade from a previously broken blade sometimes lodges in the clamp and prevents the application of full pressure on the new blade. If this is so, remove the obstruction and repeat the mounting procedure.
With the jeweler’s saw properly rigged, attention must be paid to the bench pin. This should be mounted at a height which will allow the forearm to be approximately horizontal or parallel to the floor when the saw is held against the work, with the work at the blade’s midpoint. If the bench height is not exactly right, remember that the stool upon which the worker is seated may be varied in height. The work should be held against the V block with the fingers, striving for fullest possible support and rigidity.
The blade should be perpendicular to the work. The saw motion should be up and down, with the faintest emphasis on the down, or pulling, stroke, since this is the stroke that cuts. Avoid forward pressure—the saw will seemingly feed itself. Additional pressure will only clog the teeth and make sawing more difficult and breakage more frequent. The spaces between each of the teeth determine approximately the amount of removed metal the blade will accommodate.
Forcing the blade forward will only choke the saw. Maneuver around curves naturally, just as one maneuvers a bicycle. Angular changes in the direction of sawing are more difficult and require a special technique. When a cut is to be made at a right angle, for example, cut down along the line until the point is reached where the change in direction is to occur. If one mentally likens this procedure to a boy marching in a gymnasium, assume the boy to march in the direction of the arrow. Stop at point X, and “mark time” in place. This means the saw will be moving up and down at this point, without forward progress. Now the boy, continuing “to mark time,” slowly turns a full 90 degrees until he is facing the new direction squarely. He then marches off. The saw, likewise, is slowly turned toward the new direction, continuing its normal up-and-down motion without, however, any forward progress. When facing the new direction, the saw progresses along this new path in the usual manner. The author has found that by actually using a pupil marching on a chalk line in the classroom a most effective demonstration of this technique is made.
Sticking Saw Blade
If the saw seems to stick at some particular point during sawing and resists all efforts to dislodge the blade, abandon all forcible attempts to free it. It will usually be found that the saw frame is not pointing in the same direction as the saw kerf. This results in wedging the corner of a saw tooth diagonally in the kerf. To free the blade, exert a slight upward pressure and move the frame through an arc until the saw tooth, facing the proper direction, frees itself. If necessary, free the lower end of the blade from its clamp.
Mention of the saw blade’s “tooth-corner” action brings up an important usage of the blade. When delicate sawing is done with a jeweler’s saw, and it is impossible to find files small enough to trim up the final results, a fine-toothed blade may be utilized in the following manner: Insert the blade as usual and utilize the blade as a fine file by bringing a slight sideways pressure against the kerf. If the saw is turned very slightly so that the tooth corners tend to cut against the metal, a very delicate job of trimming can be accomplished. By using a blade somewhat finer than the one used for the original job, the tendency for the teeth to “wedge” in the kerf will be eliminated.
When metal is to be removed from inner portions of a design, small holes must be drilled in the portions to be cut out. These holes are drilled after they have first been located away from the line of the design and punched lightly, using a center punch and a light hammer. The work should be placed on a steel plate or anvil and the punch mark should not be so deep as to leave a noticeable mark on the reverse side. The slight dent made by the punch will prevent the drill from ‘walking” off the design and making a hole at the wrong location. The work is then removed from the steel surface and the holes drilled. Assuming the frame to be rigged, release one end of the blade, thread through the hole, and move the work close to the tightly clamped end.. The other blade-end is reset in the usual manner. This type of “internal” sawing is called piercing.
For success in using the saw, the following further suggestions are offered:
As a lubricant on the saw blade, use beeswax or paraffin. Soap is sometimes used, but because it holds moisture it may cause rusting and consequent weakening of the blade. Draw the saw once down the cake of wax. Repeat when saw seems to “stick” frequently. A blade used with wax will pick up tiny particles of metal. The metal and the wax will fill the spaces between the teeth. This will give the appearance of a blade with no teeth. Do not be fooled by this appearance, as a blade in this condition will continue to cut quite well.
It is not necessary to rest the blade to allow it to cool.
When cutting out a design, the saw kerf (as the actual cut is called) follows alongside the line of the design. It is not necessary to leave a space between the blade and the line. However, the line must not be removed and should readily be seen on the work after sawing is completed. Good saw work necessitates only the slightest use of the files for smoothing. Space left between line and blade means actual hours wasted filing to the line.
When a zig-zag or jagged outline is to be sawed, first saw to a curve around the points of the outline. When this has been done, cut straight in from the edge to the bottom of the V. Then back out the saw blade and use either of these techniques:
1. Cut from the next point in to the same V bottom, completely removing the portion in between the sides of the V
2. Back the saw blade into the first V cut made, and when the bottom of the V is reached, turn the frame slightly and saw out along the next side of the V. This is a useful technique to remember.
If it is necessary to stop work momentarily for any reason when sawing, bring the upper clamp down to the work and the blade will be less like’y to snap when the frame is moved, either through accident or when starting to cut again. If work on a complicated design must be stopped for the day before the sawing is completed, rather than back out the blade along a lengthy and complex route, open the upper clamp so as to release the blade and pull down the frame, releasing the saw from the work.
Remember when backing out of a cut line, move the saw frame up and down just as if forward sawing were going on, only pull backward and follow the ken carefully. Always sit directly behind the saw frame. Turn the work when necessary, not the saw frame. The beginner will find that fingers holding the work will tire before the sawing arm. Rest the fingers. Never clamp the work. It is not necessary to grasp the frame handle tightly. This tires the forearm, and makes cutting no easier
There is a tendency to use the middle portion of the blade, actually utilizing about an inch of blade. Remember that 2” of blade will cut twice as much metal, and the blade has about 4” of cutting edge available!