Diamond Drill Bits

Sometimes regular drill bits aren’t strong or versatile enough to properly form holes in certain products. Hard woods, glass, quartz and other products are simply too difficult for a standard carbon steel bit to drill through. The introduction of the diamond drill bit has solved this problem by allowing the drilling of a wide variety of thick and strong materials.

Types of Diamond Drill Bits

Diamond drill bits are typically core drill bits or blunt nose bits. A core drill bit can expand a pre-drilled hole up to twice its size. It is hollow inside, with diamonds on the edge of the drill tip, and spins to cut or saw a hole. Core bits are slightly slower than their alternative, but they can be used on materials like glass, ceramic and porcelain. Blunt nose bits are full-bodied drill bits with diamonds on the tip and sides. They are used to drill fresh holes and cannot be used to expand pre-existing holes like the core bit. Because they have to drill fresh holes, the holes must naturally be smaller than core bit holes although they can later be expanded. They operate very quickly and are generally used on glass.


Core and blunt nose diamond drill bits typically feature many sharpened diamonds, but arranged in different manners. The sintered diamond method involves incorporating diamonds into the steel tip itself. Diamond bits are either embedded in the tip or mixed directly during formation. As a result, wear on the drill bit’s tip reveals new diamonds trapped on the surface. Drill bits also feature bonded diamond tips. The diamonds are bonded to the tip through plating, an inexpensive and relatively easy process that results in inexpensive tips. However, bonded drill bits must be spun slower than sintered tips because the diamonds can wear off the bit. The rate at which tips show wear is dependent on the drilling material.


In order to lengthen the diamond drill bit’s lifespan, it’s necessary to run lubrication along the bit as it cuts. This is not an expensive method because the most effective lubricant is water. Water sprayed on the bit during drilling reduces friction, in addition to cooling diamonds so they are not misshapen or discolored. There are several methods of applying lubrication to a diamond bit. Simple methods, such as squirt bottles or hoses can be attached near the bit to aim water at the bit’s cutting edge. More advanced techniques are also available, involving bottles or hoses with pumping actions. For instance, an under water feeder is very effective for very slow rate cutting. The entire material is submerged in a tub of water and the drill bit dives below the surface to drill the hole. Some other lubrication techniques can be quite simple, such as having a worker squirt water straight at the bit.

Keeping the Diamond Drill Bit Functional

Lubrication will greatly extend the lifespan of a diamond drill bit but other measures are necessary to protect your investment. For instance, drill speed needs to be carefully calculated and calibrated to the material being drilled so as to ensure wear does not become excessive. The temper of the diamond bit can be helped by lubrication, but material is also extremely important to consider. Glass and granite have totally different compositions, and can have completely different effects on diamond bits.

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