Introduction of Annular cutter
An annular cutter (also called as core drill, core cutter, broach cutter,Trepanning drill or cup-type cutter) is a hollow, multiple cutting edges cutting tool used to make/drill holes in ferrous and non-ferrous metals. An annular cutter cuts only an annular groove at the periphery of the hole and leaves a solid core or slug at the hole center. Annular cutter is a substitute for slower, more expensive and less efficient Twist drills and Hole saws. The function of Annular Cutters is more or less same as a hole saw but differs in geometry and material. Annular cutters are faster, easier and are more accurate than the conventional twist drills or drill bits.
An annular cutter or core drill removes the material from metal to create cylindrical holes in a circular cross section. An annular cutter, unlike drill bits, cuts only on the periphery of the hole to be made. Annular cutters use almost the same method as concrete core drills, but are for metal drilling. An annular cutter is a multipoint cutting tool and is made from material like high speed steel and tungsten carbide tips.
Annular cutters are available in different sizes generally starting from diameter 12 mm (1/2’’) to 200 mm (7 7/8’’) and larger if required. The length of the annular cutter can be achieved depending upon the thickness of the material to be drilled. In the market the lengths 30 mm, 55 mm, 75 and 110 mm annular cutters are popularly available. These sizes though vary from manufacturer to manufacturer. The annular cutter’s material should be harder than the material to be drilled. Therefore there are various types of material used to manufacture annular cutters, for example different types HSS and TCT material. Annular cutters are also called as core drills because, after drilling hole, the drilled material is ejected from the cutter in the form of a cylindrical blank, this blank is called a core.
The first annular cutter was invented by Mr. Dough Hougen which he patented in 1973. The High Speed Steel annular cutter was invented in 1983 by Michael Beharry and the tungsten carbide tipped annular cutter was invented in 1985 by Mikiya Toshio and Shoji Michihiro
Though people use annular cutters on conventional drilling machines like radial drilling machines or pillar drilling machine, it is not recommended because these machines have very high RPM which creates high tool breakage risk for annular cutters as they are hollow unlike solid twist drills. It is always recommended to use an annular cutter or core drill with a magnetic core drilling machine (also called as magnetic drill, magnetic base drilling machine, etc.) as these machines are slower. A magnetic drilling machine is ideally made for using annular cutters.
As an annular cutter cuts only on the periphery of the hole to be made, it has to remove much less material as compared to conventional drill bits which cut and remove the complete material of the hole. Annular cutters are considered to be 3 to 4 times faster than conventional drill bits. Also while using a twist drill bit or metal hole saw one has to do pre-drilling and step-drilling operations for bigger diameter holes, whereas an annular cutter requires no pre-drilling and step-drilling. It is a one-shot drilling operation.
The annular cutters have less teeth and less wear, therefore with an annular cutter holes can be made at higher or faster cutting speed and a faster feed rate of the drilling machine.
Since the annular cutters does not have to drill/cut through the complete piece of metal, they require less thrust and thus energy to drill is very less
The hole made using an annular cutter is more finished, precise and accurate
Due to the unique geometry of the annular cutters, making holes at awkward angles is also very easy
The cooling of annular cutters is internal. The internal lubrication is provided through a hole with the help of a pilot pin. Internal lubrication makes the annular cutter faster and more efficient for deep hole drilling
Best for light duty machines
As the annular cutters require very less RPM (from min 50 RPM only), these cutters can be easily used with light duty drilling machines or portable magnetic base drilling machines
Annular cutters biggest advantage is the variety of sizes. Annular cutters start from 12 mm diameter up to 150 mm diameter and more if required. Various cutting depth (length) of annular cutters can be sourced depending upon the requirement
A HSS annular cutter can be easily re-sharpened on a grinding machine and can be re-used for drilling. Re-grinding can be done until the desired cutting length is available on the annular cutter.
Our Major Brands of Annular cutters are: