Nowadays tools are often referred to as being made from “carbide” – what they actually mean is Tungsten Carbide. The reason for using Tungsten Carbide is it has some great properties:
- melting point 2,785–2,830°C
- hardness of 9 on Mohs scale, 2600 Vickers number
Some tungsten carbide tools consist of a mild steel shank with a piece of tugsten carbide brazed in place and then ground to shape.
A more common form now coming from the professional engineering world are mild steel shanks with replacebale carbide tips that are held in place with a single bolt.
These tools have a steel body with separate Tungsten Carbide Tipped (TCT) bits that are pre-machined to the correct angles. When the bit wears out or gets chipped then you just replace it.
Note that when machining rough castings it is very easy to chip the tools, so take that into account and use small cuts at first.
Slot drills and end mills are available as solid carbide. These keep a very sharp edge and can be used at high speed because of their higher melting point. The slot drills on the right are solid carbide and we reviewed this in a separate post – Rennie Tools Carbide Slot Drills.
Sharpening Tungsten Carbide Tools
If you want to cut a piece of Tungsten Carbide down in size then it is best to use a diamond abrasive wheel.
If you want to grind a tool to shape then green grit wheels work well. Final angles can be honed with a diamond abrasive plate.