Introduction to Hole Saws
– Hole saw is a saw blade of annular shape that creates a hole in the workpiece without cutting up the core material.
– It is used in a drill and typically has a pilot drill bit (arbor) at the center to prevent the saw teeth from walking.
– Hole saws are preferred for large holes, especially those larger than 25 millimeters (1.0 inch), as they create the hole faster and with less power.
– The depth of cut is limited by the hole saw’s cup-like shape, with common depths being 38, 45, and 60mm.
– Longer aspect ratios are available for specific applications, such as drilling through angled rooftop constructions, with depths of 165 and 300mm.
Types of Hole Saws
– Adjustable hole saw: consists of thin metal saw blade-like strips and a disc with grooves. By snapping the blades into different grooves, a hole saw of various sizes can be constructed.
– Circle cutter: another type of adjustable hole saw, known as a circle cutter, has adjustable teeth on a platform with a pilot bit. The teeth can be adjusted to cut out holes of any size, including large circles up to 300mm (1ft) and larger.
Advantages and Disadvantages of Hole Saws
– Advantages: more efficient than conventional drill bits as they remove less material, reducing the overall power requirement. They have a wider size capability, allowing for the cutting of large holes that would require specialized drill bits.
– Disadvantages: need for a portable drill with considerable torque at low speed, tendency to bind if choked with dust or wander away from the central axis. Kick-back from a powerful drill can be severe, requiring the use of long side-handles and two operators for very large holes. Core plugs often bind inside the hole saw, requiring prying after each hole is cut, and the core may twist apart mid-cut, disrupting the cutting action.
Diamond Drilling with Hole Saws
– Diamond hole saws, also called diamond core drill bits, can be used in wet and dry drilling.
– Dry drilling is not suitable for very hard materials like reinforced concrete, as it may cause the diamonds on the core bit to become blunt.
– The bond materials of diamond core drill bits are adjusted for wet and dry drilling, improving drilling speed and lifespan.
– Diamond hole saws can drill through various materials, including tile, porcelain tiles, granite, marble, concrete, metals, and lapidary materials.
References
– Degarmo, E. Paul; Black, J T.; Kohser, Ronald A. (2003), Materials and Processes in Manufacturing (9th ed.), Wiley, p.593, ISBN0-471-65653-4.
– ‘The 7 Best Hole Saws in 2023 – Best Hole Saw Kit.’ Popular Mechanics. 2023-05-04. Retrieved 2023-06-13.
– ‘Long hole saws used for deep and thickwall constructions.’ Mandrex – Extra deep and long hole saws. 2023-08-15.
– Koehler, Kenny (2022-01-20). ‘Milwaukee Hole Dozer with Carbide Teeth Hole Saws.’ Pro Tool Reviews. Retrieved 2023-06-13.
– ‘What are the advantages and disadvantages of using a hole saw?’ Wonkee Donkee Tools. 2020-02-29. Retrieved 2023-06-13. Source: https://en.wikipedia.org/wiki/Diamond_core_drill_bit
A hole saw (also styled holesaw), also known as a hole cutter, is a saw blade of annular (ring) shape, whose annular kerf creates a hole in the workpiece without having to cut up the core material. It is used in a drill. Hole saws typically have a pilot drill bit (arbor) at their center to keep the saw teeth from walking. The fact that a hole saw creates the hole without needing to cut up the core often makes it preferable to twist drills or spade drills for relatively large holes (especially those larger than 25 millimetres (1.0 inch). The same hole can be made faster and using less power.
The depth to which a hole saw can cut is limited by the depth of its cup-like shape. Most hole saws have a fairly short aspect ratio of diameter to depth, and they are used to cut through relatively thin workpieces. However, longer aspect ratios are available for applications that warrant them. Common hole saw depths are 38, 45 and 60 mm and for drilling through e.g. (angled-) rooftop constructions also a depth 165 and 300 mm is possible.
Cutting with a hole saw is analogous to some machining operations, called trepanning in the trade, that swing a cutter analogous to a fly cutter in order to achieve a similar result of annular kerf and intact core.
