DESCRIPTION All power hacksaw machines are basically similar in design. Figure 6-1 shows a typical power hacksaw and identifies its main parts, which are discussed below. Base The base of the saw usually contains a coolant reservoir and a pump for conveying the coolant to the work. The reservoir contains baffles which cause tps to settle to the bottom of the tank. A table which supports the vise and the metal being sawed is located on top of the base and is usually referred to as part of the base.... SPEED-CHANGE MECHANISM The shift lever allows the number of strokes per minute to be changed so that a variety of metals may be sawed at the proper speeds. Some saws have a diagram showing the number of strokes per minute when the shift lever is in different positions others are merely marked "F," M," and "S" (fast, medium, and slow). ADJUSTABLE FEED CLUTCH The adjustable feed clutch is a ratchet-and-pawl mechanism that is coupled to the feed screw. The feed clutch may be set to a desired amount. Because of the ratchet-and-pawl action, the feed takes place at the beginning of the cutting stroke. The clutch acts as a safety device and permits slippage if too much feed pressure is put on the saw blade. It may also slip because of a dull blade or if too large a cut is attempted. This slippage helps prevent excessiv... See full list on Metal-cutting bandsaw machines fall into two basic categories: vertical machines (Figure 6-2) and horizontal machines (Figure 6-3). Band saws use a continuous saw blade. Chip removal is rapid, because each tooth is a precision cutting tool and accuracy can be held to close tolerances eliminating or minimizing many secondary machining operations. See full list on Sawing machines have some special safety precautions that must be observed. These are in addition to those safety precautions described in Chapter 1. Here are some safety precautions that must be followed: 1. Keep hands away from the saw blade of the hacksawing machine or bandsawing machine when in operation. 2. Ensure the power supply is disconnected prior to removal or installation of saw blades. 3. Use a miter guide attachment, work-holding jaw device, or a wooden block for pushing metal workpieces into the blade of the bandsaw wherever possible. Keep fingers well clear of the blade at all times. 4. When removing and installing band saw blades, handle the blades carefully. A large springy blade can be dangerous if the operator does not exercise caution. See full list on POWER HACKSAW BLADES Power hacksaw blades differ from hand hacksaw blades in that they are generally heavier, made in longer si. Hacksaw blades are discarded when they be dull sharpening is not practical. Materialsmonly used in manufacturing power hacksaw blades are high-speed tungsten steel and high-speed molybdenum steel. On some blades only the teeth are hardened, leaving the body of the blade flexible. Other blades are hardened throughout. The set is the amount of be... BANDSAW BLADES General Bandsaw blades are manufactured in two forms. They are supplied in rolls of 50 to 500 feet for use on machines that have butt welders for forming their own blade bands. Bandsaw blades are also supplied in continuous welded bands for machines having no provisions for welding. Materials Bandsaw blades are made from special alloy steels. The blades are made flexible by annealing the body of the blade and hardening only the teeth. Set Metal cutting bandsaw blades have their teeth bent (Fi... FILE BANDS The bandsawing machine is adapted for filing by use of the band file attachment. A band file is fitted over the drive and idler wheels and in place of the bandsaw blade. The band is made up of several parts or segments which are riveted at one end (the leading end) to a spring steel band. The trailing end of each segment is free to lift during the time when the band bends over the drive and idler wheels of the band saw. When the band straightens out, the segments lock together. Figure 6-8 sho... See full list on POWER HACKSAWING Layout Power hacksaw machines are primarily intended for straight line cutting of stock to specific lengths. Laying out the workpiece consists of measuring the length to be cut and indicating the position for the cut by scribing a line on the stock. Mounting Before mounting the stock to be cut, the vise should be checked for squareness with the hacksaw blade. Place a machinist's square against the blade and the stationary vise jaw. Adjust the jaw, if necessary, at 90� to the blade. If the wor... Vise The vise must be securely tightened on the workpiece to prevent loosening during cutting. Blade breakage might result from shifting workpieces not clamped tightly in the vise. HORIZONTAL BAND SAWING MACHINES The stock should be measured and the position of the cut machinist's square or a protractor against the bandsaw blade and the stationary vise jaw. Position the stock in the vise so that the saw blade aligns with the scribed line on the stock. If. more than one piece is to be cut to the same size, move the stock stop arm against the end of the stock and lock it in place. Additional pieces can then and moved up against the stop to produce pieces equal in length to the first piece See full list on Efficient sawing with sawing machines requires sharp saw blades in good condition. To prevent dulling and breakage of saw blades, proper speeds and feeds must be maintained. The speed of the saw blade for any specific operation depends upon the nature of the material being cut. See full list on INTERNAL SAWING Internal sawing is performed in the same manner as contour sawing except that the bandsaw blade cannot start cutting from the edge of the workpiece but must start cutting from a drilled hole in the workpiece (Figure 6-20). With the pattern laid out on the workpiece and the starting hole drilled, insert an unwelded bandsaw blade of the proper length through the starting hole. Bring the two ends of the blade together at the butt welder of the bandsawing machine and weld the blade into a continu... BAND FILING Filing is performed on the vertical band saw machine using a band file and the band file attachment. As with sawing, the quality of filing and the economical wear of the band file depend upon proper selection of files and filing speeds for different materials and conditions. Band Filing Speed Band files should be run at relatively slow speeds aspared to speeds used for band sawing. Figure 6-21 lists rmended speeds for band filing. Note that, in general, the slower speeds are used for... POLISHING Polishing bands and a polishing attachment are provided with the vertical band saw machine so that light polishing can be performed. The polishing bands are intended primarily for removing saw marks on the cut edges of workpieces. Polishing Speeds Move polishing bands at speeds between 75 and 260 FPM, the faster speeds being used for softer materials and the slower speeds being used for harder materials. Polishing Feeds Feeds should be light for polishing. Use a slow, sideways motion so that... See full list on
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