Why Drill Metal with Annular Cutter (Mag Drill Bits) in Magnetic Drill?
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What is an Annular Cutter (Mag Drill Bits)?
Features of Annular Cutter
Why Drill with Annular Cutter (Mag Drill Bits)?
What are Annular Cutter (Mag Drill Bits) Used For?
How to Choose an Annular Cutter (Mag Drill Bits)?
What is an Annular Cutter ( Mag Drill Bits ) ?
An
Annular Cutter, with a center free annulus bell shape, is used to make holes in
metal. It is also known as mag drill bits which is named after the use
in
magnetic drilling machine. Usually, annular cutters are available in
Tungsten Carbide Tipped (TCT)
and
High Speed Steel (HSS).
Features of Annular Cutter
Tungsten Carbide Tipped (TCT) Annular Cutter
Tungsten carbide (WC) is sharper than most materials and about 2 times
harder than steel. It also has hot hardness at high temperatures
allowing faster drilling speed. Besides, tungsten carbide has a very
high wear resistance and its thermal expansion is less than steel. Due
to the TCT cutting edge, the annular cutter can drill hard materials
with a high quality performance.
High Speed Steel (HSS) Annular Cutter
HSS can withstand higher temperatures and keep its hardness to drill
faster than carbon steel, like the name of high speed steel. Mostly, the
HSS annular cutter is made from
M2
steel. In order to drill harder materials, cobalt will be added to steel
to make
M42
type HSS annular cutters. If the cutter becomes blunt, it can be
re-sharpened to use again.
Hollow Core Design
The hollow core design provides the annular cutter an efficient and
quick way to make holes in metal. Compared with conventional drill bits,
annular cutters only contact with the metal by the outer perimeter to
cut the periphery of the hole, instead of removing the whole area of the
hole, and leave a solid slug with less chips.
Multiple Cutting Teeth (for TCT)
The multiple cutting teeth geometry has a faster start drill because it
distributes the cutting surface evenly to lower the friction when
drilling the material.
Flute
During the cutting process, the heat from drilling will transfer to
chips and cause chips to expand which may result in a stuck annular
cutter in the hole. The design of flute can lead the chips out of the
hole smoothly to avoid overheating and jammed.
Weldon Shank
Weldon shank is widely used with magnetic drilling machines. The 2 flat
system will be securely held to prevent from rotating and moving when
start drilling. This provides the annular cutter a longer tool life as
well as an accurate and burr-free hole. Also, you can use an adapter
(from Weldon to your shank type) for the annular cutter to fit different
magnetic drilling machines.
Hole for Pilot Pin
There is a hole in the center of the shank for pilot pin to go through.
A pilot pin plays a very important role in annular cutters. Here are
three functions it provides:
- A pilot pin helps the annular cutter align the center point of the hole.
- The pilot pin will retract into the magnetic drill while starting drilling. This allows the internal coolant to flow down to the cutting teeth of the annular cutter.
- When finishing drilling, the retracted pilot pin will eject the slug.
Titanium Nitride (TiN) Coated and Titanium Aluminum Nitride (TiAlN) Coated
Coated annular cutter is stronger and more durable than standard type.
Coating can prevent the cutter from rust to prolong the tool life. This
coating process allows annular cutters to increase the cutting speed and
drill hard materials.
CBN (Cubic Boron Nitride)-Ground
Cubic Boron Nitride (in a cubic crystal structure) is a super hard
material after diamond. With properties of superior thermal stability
and chemical inertness, CBN is widely used for grinding cutting tools
while diamond will deteriorates when contacting with steel. CBN
processed annular cutter has a better cutting performance by sharp
flutes and cutting edges.
Why Drill with Annular Cutter ( Mag Drill Bits ) ?
Benefits and Advantages of Annular Cutter
- Fast (Time Saving)
Since an annular cutter removes only the material at the periphery of
the hole, it is 3 to 4 times faster than twist drill bit.
Besides, an annular cutter with pilot pin can finish a hole by one
operation without pre-drilling for a pilot hole.
- Efficient (Energy Saving)
Due to the annulus shape and thin wall design (4mm for each diameter),
the annular cutter does not have to drill the complete material of the
hole which lowers the energy, effort and thrust compared to conventional
drill bits.
- Less wear (Longer life)
While the cutting surface is distributed to multiple cutting edges, the
contact between annular cutter and the material becomes much less.
Also, no matter how big the hole you are going to drill, the thin wall
(4mm) of the annular cutter will cut only at the periphery of the hole.
Therefore, an annular cutter with a good design has a longer service
life with best performance.
- Clean Hole (Burr-free)
With specially designed cutting teeth geometry compared to conventional
drill bits, an annular cutter can create a burr-free hole in metal.
Besides, since there is only a few chips made, the cleaning work after
drilling is very easy and fast.
What are Annular Cutter (Mag Drill Bits) Used For?
Material
Cast Iron
Carbon Steel
Hardox
Heat Treated Steel
High Tensile Steel
Metal Sheets
Structural Steel
Stainless Steel
Stacked Steel
Thick Plate Steel
How to Choose an Annular Cutter (Mag Drill Bits)?
Depth:
One of the cutter size determination. The depth will be longer than the
thickness of the material you are going to drill.
Diameter: Outer diameter of the cutter. For small diameter holes, you can choose
a HSS annular cutter. If you need a bigger hole, TCT annular cutters are recommended.
Type of the Material: If you need to drill harder material, TCT or Tin/Tia coated annular
cutter is a better choice.
Shank:
Annular cutters with Weldon shank can be used with most magnetic drills.
If the mag drill you have cannot fit Weldon shank, you can use an adapter.
Support
As we are specialized in Cutting Tools, custom sizes of annular cutters for up to 200 mm in diameter and
250 mm in cutting length are available. We have helped customers solve their problems of cutting holes. You
can search more information on our product category page of
Annular Cutter.
If you have any further questions, please do not hesitate to
CONTACT US.
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