Bi-metal hole saws and the application
The bi-metal hole saws are suitable not only for metal cutting but also for wood processing. The bi-metal hole saws are available in HSS( M3, M2, M35) and HSSE-Co 8 (8% cobalt).
Characteristics of bi-metal hole saws
The main body and the cutting edges of the bi-metal hole saw consist of two different tool steels. The main body consists of a special carbon steel and the teeth that cut the material are made of HSS or HSSE-Co 8.
The teeth are welded to the main body. The two bi-metal hole saws have two different toothings:
HSS with varied toothing
HSSE-Co 8 with fine toothing
The varied and fine toothing ensure that the hole saw does not get caught in the material and runs smoothly. Bi-metal hole saws have a larger number of cutting edges than carbide hole saws, which allow a clean cut.
To drill a hole with the bi-metal hole saw you also need a arbor holder with guide drill.
Arbor holder with guide drill
Since the hole saw and holder are separate, you can quickly change the different hole saw diameters (available from us: 14 to 210 mm) with the arbor holder. The guide drill allows simple centering and clean guidance in the material. There are different holders for the corresponding drill chuck.
Optionally, you can also use an ejector spring that ejects the cut material from the hole saw.
Application of bi-metal hole saws
The bi-metal hole saws are best suited for cutting of metal and wood. Best results are achieved in steel up to max. 5.0 mm material thickness.
The areas of application are mainly in sanitary and electrical installations.
When cutting steel or metal, pay attention to the correct number of revolutions. In the speed table for bi-metal hole saws you will find the corresponding speeds.
Bi-metal hole saw HSS with varied toothing
With easily cutable materials such as aluminium, wood or plasterboard, the varied toothing clears the cut material better. Compared to the bi-metal hole saw HSSE-Co 8 with fine toothing, the cut is slightly coarser.
It is often used to drill holes for sockets and light switches (68 mm diameter) and cable ducts in desks or kitchen worktops.
Bi-metal hole saw HSSE-Co 8 with fine toothing
The high cobalt content ensures high hot hardness. This means that the tool steel does not lose its hardness at high temperatures.
The fine toothing ensures a smoother running, better cutting pattern and less effort.
For these two reasons (high heat hardness and clean cut) the bi-metal hole saw HSSE-Co 8 particularly suitable for metals such as unalloyed and alloyed steel (up to 5 mm) and less for soft materials.
Compared to the bi-metal hole saw HSS, the lower heat generation during cutting increases the service life, especially with metals.
Bi-metal hole saw Fields of application
HSS with varied toothing Unalloyed teel up to 5 mm cutting depth (up to 700 N/mm2), non-ferrous and light metals, plastics, plasterboard, and light building boards, fibreboard, plywood and wood
HSSE-Co 8 with fine toothing alloyed and non-alloyed steels (up to 1,000 N/mm2), high chromium alloyed steels such as stainless steel, steels resistant to rusts and acids, non-ferrous and light metals (aluminium)
When drilling alloy steels you should use coolant.