Annular cutter
An annular cutter, named after the annulus shape, cuts only a groove at the periphery of the hole and leaves a solid core or slug at the center.
[1] An annular cutter is a more expensive and efficient alternative to spiral drill bits and standard hole saws.
The two most common types are high-speed steel (HSS) and tungsten carbide tipped (TCT).
[4] As an annular cutter cuts only on the periphery of the hole to be made, which cuts and removes the complete material of the hole, annular cutters are considered to be 3 to 4 times faster than conventional drill bits.
[5] Because annular cutters do not have to drill/cut through the complete workpiece, they require less thrust and thus less energy to drill through material.
Internal lubrication makes the annular cutter faster and more efficient for deep-hole drilling.
[6] HSS annular cutter can be easily re-sharpened on a grinding machine and can be reused for drilling.
[citation needed] HSS core drills are made from high-speed steel material.
This makes the core drills more resistant to heat, longer tool life, and even removal of chips.
[citation needed] A Standard TCT core drill has tungsten carbide tips.
The biggest advantage of hard-coated core drills is that these cutters are very good for cutting larger diameters on hard material.
[citation needed] "Weldon shank" annular cutters have 2 flats and this is the traditional method adopted by many of the popular magnetic drill manufacturers.
"Weldon shank" annular cutters fix in the chuck by tightening grub screws in the two flat areas.
This is also a popular method for using annular cutters into mag drills quickly, without any strain of tightening grub screws.
To make a hole in a tube or pipe easily an annular cutter should be used with a magnetic base drilling machine and a tube/pipe clamping device.
With the help of magnetic drilling machines' proper RPM, the annular cutter makes a perfect hole in the tube.
Generally, a HSS annular cutter is used to make holes in tubes and pipes, as the TCT annular cutters have more chances of cutting teeth breakage due to curved surfaces of tubes and pipes.
Annular cutters distribute the load equally on the periphery of the hole with its multiple cutting edges, thus the required thrust and energy are also much less comparatively.
Especially for boring larger diameter holes in hard materials, TCT core drills can be used to great success.
The teeth on TCT core drills are harder than HSS, allowing them to cut more difficult materials.
They are also more difficult to remove if stuck, as they have a larger contact area with the workpiece than a regular drill bit.
The ejector pin (also called a pilot pin) has three major functions:[citation needed] The magnetic drilling machines are provided with speed gears and some machines are also equipped with variable speed control.
