Pillar exercise jargon for beginners
When I started with the abutment drills, I found all the terms for the different parts and measurements really confusing. This article is designed to help you if you are trying to choose an exercise and you need to understand what all the terminology and jargon means.
Parts found in column drills
- Drill head: the assembly that forms the chuck, the spindle, the bit, the motor and the pulleys.
- Base – The heavy “foot” of the machine that is bolted to the floor in the case of a larger drill press or the workbench in the case of a smaller drill press.
- Column – This is the vertical abutment that gives the abutment drill one of its names (confusingly, its other common names are “bench drill” and “press drill”).
- Spindle – The vertical axis that is in line with the bit and connects the chuck to the drill head.
- Chuck – The assembly that fits onto the spindle and holds the bit.
- Table – Sometimes little more than a ledge on smaller bench drill models. It is the support of the workpiece to be drilled and is fixed to the column at a certain distance below the head and above the base. Tables can be rectangular or round, and some can be tilted to allow drilling at an angle through a workpiece. Column drill accessories can be purchased to clamp or hold workpieces at various angles.
- Depth Gauge – An adjustment that allows the bench drill to drill a hole in the middle of a workpiece.
The meaning of the measurements in the bit specifications
- Throat Distance – This is the measurement from the closest edge of the pillar to the center of the shaft.
- Swing – This is a common measure of the capacity of column drills and is defined as twice the throat distance, or to put it another way, the maximum disc size that a center hole can be drilled into.
- Spindle Taper – Defines the shape of the spindle end. There are long, short, female and male types. The chuck must be compatible with the spindle taper.
- Collar Diameter – This is the outside diameter of the collar or chuck assembly that holds the bit.
- Chuck Size – This is the diameter of the inside opening of the chuck assembly, thus it defines the maximum size of the bit shank the drill can take. Because of this it is also known simply as the piercing capacity.
- Spindle Travel – This is the amount the spindle can be lowered or raised vertically and defines the maximum hole depth it can drill in one pass.
- Maximum distance from axis to table: This distance defines the deepest workpiece that you can place on the table.
- Max Axle to Base Distance – This is similar to the above and defines the maximum depth of the workpiece that you can drill without the table.
