Carbide Burs as we all know are majorly used to cut, shape, grind and remove burrs, sharp edges and excess material.
- Materials that Carbide Burrs be used on?
You can use carbide burrs on a wide range of materials including aluminium, steel, cast iron, wood, fibreglass, cobalt, nickel, acrylics and plastics. You can also use it on gold, platinum, titanium, fibreglass and silver. Carbide burrs are the ideal cutting tool because they last a long without breaking as long as you use them the right way.
Different types of materials are suited to unique cuts of carbide burrs. You will learn about that as you read on.
Carbide Burrs comes in 2 Cuts;
a. Single Cut
Single Cut is also known as on flute. These types of burrs have a spiral flute on the right side. Stainless steel, copper, hardened steel, and cast iron are examples of those materials you use single cut for. They will easily remove material quickly with a smooth finish. A single cut burr is perfect for milling, heavy stock removal, cleaning, deburring and milling.
b. Double Cut (Diamond Cut)
Double cut burrs are used on metals, steel, aluminium, plastics and wood. They come with more cutting edges and hence, tend to remove materials at a faster rate. Also known as diamond cut, they have a smoother finish when compared to the single-cut burr. They are perfect for deburring, finishing, cleaning and stock removal. It is the most popular cut out there.
2. Shapes of Carbide Burrs and Ways to Use Them
The shape of the burr you choose will depend on the result you want to achieve. There are several shapes of carbide burrs. They include:
Carbide Ball Burrs
It is a spherical shaped carbide burr. With it, you can make circular cuts into your material or carve out a hollow shape. It’s a must-have for wood and stone carvers, metal engravers in a micro motor or a high-speed handpiece.
Whenever you want to use it, make sure you use a handpiece that has no wobble.
Carbide Tree Burrs
They are used to round off edges as well as making concave cuts. The pointed end is used to cut areas that are hard to reach and angled contours.
Carbide Inverted Cone Burrs
It is for making v-cuts and rear side chamfering
Carbide Pointed Cone & Carbide Round Nose or Ball Nose Burrs
The shape of burrs is perfect for surface finishing and round edges. It can reach difficult areas and narrow contours. The shape is also known as to as a tapered shape.
Cylinder Burrs. Round Nose/Ball nose/End Cut
Cylinder burr with end cut cylinder is a perfect tool for contour finishing. The cylinder burr without end cut is for contour finishing and right-angled corners
Oval Burrs
Oval Carbide burrs are made for a wide range of stock removal and grinding operations. They are useful on a wide range of materials, such as metal, ceramic, plastics and even wood
Wheel Shaped Carbide Burrs
It has a smooth top with round edges and fluted sides used for shaping and channel work.
Countersink Burrs
It is perfect for bevelling, chamfering, counter-boring. It can also reach difficult angles when working areas of your work.
3. What Speed or RPM should you use your Carbide Burrs?
This recommendation is a key one as it determines the life of your tool. The speed used is dependent on two factors
- The material you want to use it on
- The contour produced.
Before we go on, know that it is safe to run on speeds lesser 35,000 RPM.
Check the table below for the appropriate speeds.
If your burs chip easily, it means the speed is too slow. When working, you need to start slowly and increase the speed as you progress. Running on high-speed help to prevent your burs flute from clogging.
| Diameter of Burr | RPM |
| 1.6mm or 1/16″ | 25,000 – 35,000 |
| 2.35mm or 3/32″ | 17,000 – 26,000 |
| 3mm or 1/8″ | 17,000 – 26,000 |
| 6mm or 1/4″ | 11,000 – 16,500 |
| 12mm or 1/2″ | 8,000 – 12,000 |
| 16mm or 5/8″ | 7,650 – 11,500 |
Note: For Applications with low stock removal (deburring, chamfering), you can increase the rotational speed by 100%. Use the highest rotational speed possible within the recommended speed.
4. Do Not Apply Too Much Pressure
While using the burrs, only apply little pressure and let the burr do the work. Applying lots of pressure will only lead to chipping of the flutes of your burr and it will reduce the life of your burr.
5. Keep the Carbide Burr On The Move
Do not keep your carbide burr still for long. Doing this prevents the burr from digging into your material causing unwanted marks. Use an ‘up’ stroke for a smooth finish when ending your work.
6. Carbide Burrs are Harder Than HSS Burrs
Carbide Burrs are machine ground from a specially chosen grade of carbide. Due to their extreme hardness, Tungsten Carbide fit more demanding jobs than HSS (High-Speed Steel). Carbide Burrs also perform better at higher temperatures than HSS so you can run them hotter, and for longer.
HSS burrs will start to soften at higher temperatures, so carbide is always a better choice for long term performance.
7. Use Highly Powered Drives
Mount Carbide Burrs on highly Powered Drives with elastically mounted spindles to avoid vibration. For the cost-effective use of burrs, use a power tool with an output between 300-500 watts.
8. Only Use One-Third Of The Burs Surface Area
The bur surface in contact with the material to be machined must not exceed 1/3 of the bur surface. Not complying with this recommendation results in rough milling and broken teeth. If this cannot be avoided, it is recommended that you use the tough cut.
9. Apply Burs Counter-rotationally
Use tungsten carbide burrs in a swinging motion or counter-rotationally. This helps to achieve finer finishes. You can also pass the burr rapidly over the workpiece in the direction of rotation
Avoiding Misuse
| Figure | Consequences of Misuse | Solution |
|
The carbide burr becomes clogged during use | Use the correct cut for the material being machined.
Use a grinding oil or use tools that have a HICOAT coating. |
|
a. Discolouration between tooth and shank
b. The head breaks off from the shank |
a. Observe the recommended speed and reduce the contact pressure and surface contact angle.
|
|
You can see sparks flying | Reduce the rotational speed and reduce the contact pressure to not more than 1/3 of the bur’s surface |
 |
Head is chipped severely | Avoid impact loads when using the carbide bur |
 |
The shank breaks | Only use rigid power tools and undamaged clamping systems and replace them when you should. |
|
The clamping length is incorrect | Use a bur clamping length that is at least 2/3 of the shank’s length. |
|
The shank bends on extended shank burs | Observe the recommended rotational speed and safety notes for extended shank burs |
|
Signs of wears including rough running, strong vibrations and increased flying spark. | Avoid using the burr till the end of their service life. You need to buy a new burr. |
Safety Precautions
- Always ensure your burr shank is well inserted into your collet and clamped down tightly
- Keep pressure light and keep the bur moving, focusing on the highest material first
- Ensure your work is secured tightly to your workbench
- Don’t snag or jam your burr into your work
- Wear eye protection as a minimum, but better still use a full shield for your face
- Wear hearing protection
- Wear protective gloves to prevent cuts from sharp objects
- Make sure you handle the power tool with both hands.
- Always use the recommended rotational speed
- Read Safety Data Sheets before making use of any tool.
Conclusion
For a long-lasting and efficient use of your carbide burrs, make sure you follow all the recommendations and precautions listed above. Use the right type of bur on the appropriate material, replace worn out parts and you will be glad you did.