BANDSAW OPERATIONS - OD1646 - LESSON 1/TASK 1
(a) Laying Out Pieces for Circular Sawing. When a circle or disk is to
be sawed using the disk cutting saw attachment, a compass or pair of
dividers should be used to scribe a circle of the desired diameter on the
stock. If possible, the circle should be scribed beginning at one edge of
the stock so that the bandsaw blade may start the cut without preliminary
sawing or notching. Next, a center hole should be drilled or center-punched
into the disk to accept the center pin of the disk cutting attachment. The
hole should be made only as deep and as large as needed for the center pin.
Too large a hole will cause the center pin to fit loosely, which will result
in an inaccurate cut.
(b) Laying Out Pieces for Contour Sawing. When an outline is to be cut
that consists of more than two intersecting lines, the exact shape required
should be scribed on the stock. When laying out the piece, save unnecessary
cuts by taking advantage of straight, clean edges on the uncut stock. The
bandsaw blade size should be selected according to the size needed to cut
the smallest radius laid out on the workpiece. Then a twist drill equal to
or greater in diameter than the width of the bandsaw blade must be selected.
Using this drill, drill a hole in the solid stock in each corner of the
pattern (figure 16 on the following page), making sure the holes fall
completely within the section of material that will be removed. These holes
are needed when sawing to permit the change of direction of the bandsaw
blade from one cut to the other.
If an internal section is to be removed from the stock, and the edge must
remain unbroken, lay out and drill a starting hole, using a drill larger in
diameter than the width of the bandsaw blade.
The bandsaw blade will be
inserted through this hole before being welded into a band and installed on
the bandsaw machine.
(7) Bandsaw Speeds and Speed Controls. The cutting speed of a bandsaw
machine is the speed of the bandsaw blade as it passes the table, measured
in feet per minute (fpm). Proper bandsaw speeds are important in conserving
bandsaw blades.
Too great a speed for the material being cut will cause
abnormally rapid blade wear.
Too slow a speed will result in inefficient
production. In general, the harder the material, the slower the speed that
should be selected. Conversely, the softer the
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