It is almost impossible to drill hardened, high-speed or alloy steel with conventional drills, and those designed for this are very expensive, require constant correction and also fail. To drill the above-mentioned steels, we will use cheaper tools - concrete drills, but sharpened in a special way. This job requires some skill with drill bits.
Will need
- drills for concrete with a diameter of 10 and 6 mm (or any others) - http://alii.pub/5zwmxz
- CBN sharpening disc;
- tool for sharpening drills.
The process of sharpening a concrete drill for drilling hard steels
Drills for metal and concrete even look different from each other. If the former have an equal diameter along their entire length, then the latter are equipped at the end with a strong plate, the ends of which noticeably protrude beyond the body of the drill itself.
You won’t be able to just grab and start drilling metal into concrete. This requires a radical re-sharpening. There are many ways to do this operation, we will use one of them.
To prevent the drill body from creating unnecessary friction on the metal surface, and therefore reducing the drilling temperature, we cut off the tool body at the end on both sides of the plate.
Now we proceed to the three most important sharpening actions: we reduce the sharpening angle of the cutting edges of the plate to 10 degrees and round off (backing) the drill.
Also, at the top of the drill, we grind off the metal plate on both sides to remove the bridge, which is formed when sharpening the cutting edges and has low strength.
All of the above and auxiliary sharpening operations are performed on a CBN machine, using a tool for sharpening the drill.
Drilling carbide and hardened steels with a concrete drill
First, on a drilling machine, using a sharpened 6 mm concrete drill, we drill a hole in a mechanical saw blade made of high-speed steel. The operation proceeds quickly and the drill receives virtually no damage.
Drilling with a hardened high-speed steel flat file takes longer and is not as easy, but still the drilling is completed in an acceptable time and with minimal damage to the tool.
After these two operations, the drill was slightly damaged. At the exit of the drill from the file, part of the cutting plate was torn out from one end, which was expected in advance. To avoid this defect, it is necessary to further reduce the sharpening angle or place softer steel under the quick cutter.
Considering the low cost of drills for concrete compared to special drills for processing strong steels, the use of the first tool with regrinding is fully justified.
High-quality drills on AliExpress at a discount - http://alii.pub/5zwmxz
Watch the video
How to make a device for sharpening drills from simple materials - https://enn.washerhouse.com/8180-kak-sdelat-prisposoblenie-dlja-zatochki-sverl-iz-prostyh-materialov.html
