CAUTION

Before operating a pneumatic tool, inspect the air hose and check it for leaks or damage. Blow air through the air hose to free it of foreign material before connecting it to the tool. Keep the air hose clean and free from lubricants. Never point the air hose at another person.

Pneumatic tools must have complete lubrication. The moving parts of pneumatic tools are fitted very closely, and they must be lubricated correctly or they will wear quickly and fail to work.

Valves and pistons on pneumatic hammers require a light machine oil. Since the compressed air comes directly in contact with these parts, it has a tendency to drive the lubricant out through the exhaust.

When working continuously with a pneumatic tool, you should regularly check the lubricator to ensure there is ample lubricant available. Next, empty the filter assembly as needed.

On low-pressure compressed air systems that do not have the filter, the regulator, and the lubricator assembly installed, you should disconnect the air hose every hour or so and squirt a few drops of light oil into the air hose connection. Do NOT use heavy oil because the oil will cause precision parts to either fail or to have operating troubles. If this occurs, you have to clean your tool in cleaning solvent to loosen the gummy substance that results. Blow out the tool with air, lubricate it with light oil, and go back to work.

Keep your pneumatic tools clean and lubricated and you will have few operating problems.

SHOP MACHINERY

Prefabrication of steel parts and assemblies is typically accomplished in a steel shop where heavy steel working machinery is accessible. The steel shop is tasked with manufacturing and fabricating items, such as sheet-metal ducts, pipeline section fittings, plates, and angles. In the following sections, we will discuss some of the common types of machinery found in a well-equipped steel shop.

COMBINATION IRON WORKER

The combination iron worker is likely the most valuable and versatile machine in a shop. The combination punch, shear, and coper (fig. 12-8) is capable of cutting angles, plates, and steel bars, and it can also punch holes. The size of the angles and plates that can be safely handled by the machine depends upon its capacity. It is manufactured in various sizes and capacities, and each machine has a capacity plate either welded or riveted on it. This guide should be strictly adhered to. The pressure and power the machine develops demand extreme caution on the part of the operator.

VERTICAL BAND SAWS

While the vertical band saw is designed primarily for making curved cuts, it can also be used for straight cutting. Unlike the circular saw, the band saw is frequently used for freehand cutting.

The band saw has two large wheels on which a continuous narrow saw blade, or BAND, turns, just as a belt is turned on pulleys. The LOWER WHEEL, located below the WORKING TABLE, is connected to the motor directly or by means of pulleys or gears and serves as the driver pulley. The UPPER WHEEL is the driven pulley.

The saw blade is guided and kept in line by two sets of BLADE GUIDES: one fixed set below the table and one set above with a vertical sliding adjustment. The alignment of the blade is adjusted by a mechanism on the back side of the upper wheel. TENSIONING of the blade - tightening and loosening-is provided by another adjustment located just back of the upper wheel.

Cutoff gauges and ripping fences are sometimes provided for use with band saws. However, you will do most of your work freehand with the table clear because accurate cuts are difficult to make with a band saw when gauges or fences are used.

The size of a band saw is designated by the diameter of the wheels. Thus the 14-inch model (fig. 12-9) has 14-inch wheels. Common sizes are 14-, 16-, 18-, 20-, 30-, 36-, 42-, and 48-inch machines. The 14-inch size is the smallest practical band saw. With the exception of capacity, all band saws are much alike in maintenance, operation, and adjustment.

Blades, or bands, for bandsaws are designated by POINTS (tooth point per inch), THICKNESS (gauge), and WIDTH. The required length of the blade is found by adding the circumference of one wheel to twice the distance between the wheel centers. Length can vary within a limit of twice the tension adjustment range.

Vertical band saws are comparatively simple machines to operate. Each manufacturer publishes a technical manual for their machine. Refer to the