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How to sharpen used and dull tricone drill bits?

Views:35     Author:Site Editor     Publish Time: 2020-03-19      Origin:Site

Have you tried drilling recently and found that the tricone drill bit couldn't cut as it used to be? Maybe some of your drill bits are so blunt, that they can't even penetrate wood or soft metal. Try this simple technique before you go to the hardware store to buy a new tricone drill bit. It saves a lot of time and money! Please follow the steps below to convert used, blunt, broken, broken, or other useless tricone drill bit into a brand new one. Sharpening tricone drill bit is also a tricky task, so extra care should be taken.

Tricone Bit

This article contains the following aspects:

Materials and tools

Why drill bits chip and dull

Steps of sharpen used and dull drill bits

Top tips for keeping drill bits sharp



1. Materials and tools:

Blunt tricone drill bit, grinder, goggles, work gloves (optional), ice water container, scrap wood.

*Some people believe that wearing work gloves will reduce the ability of drilling safely. So you can choose to wear gloves, but you must wear goggles.

2.Why drill bits chip and dull

To let you know how to sharpen your tricone drill bit better, you should know why you have to do this. Because the ground force behind the rig can not withstand the force applied by the drilling operation,  there is a gap on the rig. So make sure your landing has a curved shape to it. This curve shape increases the support for the lip. When the chisel can not smear the material on the blade, it will cause the tricone drill bit to become dull and need to be re-defined on the surface of the bit. Alternatively, the lip is rolling and need to be quickly re-sharped, so that it pushes directly into the work-piece.

3.Steps of sharpen used and dull drill bits

A.The first step is to examine your blunt head. Your goal is to remove enough metal to get a sharp edge. Many table grinders have two grinding wheels, one for rough grinding and one for fine grinding. If the bit does break, start with the thick wheel and switch to a thinner wheel in the process. If your tricone drill bit looks good, start with a thinner grinding wheel. Many functions on the  tricone drill bit can be re-defined. To increase speed, focus on the three basic features of the tricone drill bit: the lip, the ground, and the chisel.

B.Put on the goggles and turn on the grinder. Hold the tricone drill bit firmly so that the edge is completely parallel to the front of the wheel. Slowly and carefully move the tricone drill bit until it touches the wheel. Do not turn or rotate it, as long as straight and fixed at a factory angle of 60 degrees.

C.Keep the tricone drill bit at this angle for no more than 4-5 seconds. Remember: your goal is to simply grind out the matte surface, not the worn parts. The point is to grind the tooth surface of the tricone drill bit , the intersection of the tooth tip and the torque shaft. Not at the sharpening edge to achieve the desired angle. If the angle is not steep enough, the tricone drill bit will not be able to drill smoothly.

D.After grinding for 4-5 seconds, pause and dip the tricone drill bit into ice water to cool. If not, the tricone drill bit will become too hot to hold and even wear the metal faster, reducing the effective life of the tricone drill bit. Once the drill bit is cooled to the contact point, check if it is welldone on the side you have just processed.

E.When meeting the points on the first side, rotate the bit 180 degrees using the same grinding and cooling process on the other side. with a 60 degree angle as the target, the angle and point width on both sides of the tricone drill bit are the same, allowing the tool to bore straight holes. To ensure the same sharpness, some choose to grind a tricone drill bit on each side, holding the tricone drill bit with their dominant hand, turning 180 degrees every few seconds.

F.Once the drill tip is in contact with the ground point, both sides are sharp and the width is the same, you can test the tricone drill bit. Place the tip of the knife vertically on a piece of waste wood and turn the tricone drill bit by hand. Even with this slight pressure, a well-ground drill will produce the beginning of a hole. If not, recheck the tips and return to the wheel. Once again, strive for an ideal 60 degree slope point with equal width on both sides.

G.Once you have confidence in the sharpness of the tricone drill bit, insert it into the tricone drill bit, pick up the scrap wood and start drilling. It should “bite ” the wood with minimal pressure, and when you remove the tricone drill bit from the wood, you should throw out the sawdust when the wood is exposed.

4.Top Tips for Keeping drill bits Sharp

Once you have successfully mastered how to improve your tricone drill bit, you can use these three  practices to stay on the cutting edge.

A.Every inch or so, take out the tricone drill bit and blow off every flakes or debris. Otherwise, the chip will get stuck in the groove of the tricone drill bit and become very hot. The higher the drill temperature, the faster the grinding speed and the more grinding times required.

B.Form a habit of stopping and cooling techniques, especially when drilling hardwoods. Just put a container of cold water nearby and soak the tricone drill bit every few inches for a few seconds.

C.Keep two full sets of tricone drill bits. Some professionals rely on a similar set of new tricone drill bits to start drilling. In order to make the tricone drill bit sharper, they will switch to the older, sharper one after the drilling is finished, which will increase its life.


Remember that sharpening is a very complex process. This article provide a way, even it isn’t perfect, but if you do it correct, this technology will save you money and add more life to your tricone drill bit, so you can get back to work soon. If you have any other doubt or interest, consult us please.



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