Drilling Machine Essay

gure 1.6 Geared Drilling Machine

A geared head Drilling Machine is a Drilling Machine in which power transmission from the motor to the spindle is achieved solely through spur gearing inside the machine's head. No friction elements (e.g., belts) of any kind are used, which assures a positive drive at all times and minimizes maintenance requirements. Gear head drills are intended for metalworking applications where the drilling forces are higher and the desired speed (RPM) is lower than that used for woodworking. [21]

Levers attached to one side of the head are used to select different gear ratios to change the spindle speed, usually in conjunction with a two- or three-speed motor. Most machines of this type are designed to be operated

As it is possible to swing the arm relative to the machine's base, a radial arm Drilling Machine is able to operate over a large area without having to reposition the workpiece. This saves considerable time because it is much faster to reposition the drill head than it is to unclamp, move, and then re-clamp the workpiece to the table. The size of work that can be handled may be considerable, as the arm can swing out of the way of the table, allowing an overhead crane or derrick to place a bulky workpiece on the table or base. A vise may be used with a radial arm Drilling Machine, but more often the workpiece is secured directly to the table or base, or is held in a fixture. Power spindle feed is nearly universal with these machines and coolant systems are common. Larger size machines often have power feed motors for elevating or moving the arm. The biggest radial arm Drilling Machines are able to drill holes as large as four inches (101.6 millimeters) diameter in solid steel or cast iron. Radial arm drills are specified by the diameter of the column and the length of the arm. The length of the arm is usually the same as the maximum throat distance. The Radial Arm Drill pictured in this article is a 9-inch column x 3-foot arm. The maximum throat distance of this drill would be approximately

It is essentially a proxy for the continuous torque the machine is capable of producing. Typically a given drill will have its capacity specified for different materials, i.e., 10mm for steel, 25mm for wood, etc. [24]

For example, the maximum recommended capacities for the DeWalt DCD790 cordless drill for specific drill bit types and materials are as follows:

Table 1.1 Capacity of Drilling Bit

Material
Drill bit