Proper Use of Drill Bits on CNC Machining Centers

DSC_0019Using solid carbide drill bits in a standard collet on a CNC router often leads to vibrations causing a poor finish and tool breakage which can get expensive if you are drilling hard wood or composite materials (as a note – PCD diamond tipped drill bits are recommended for composites). When compared to spiral router bits, drill bits are run at a slower RPM generally and while breakage might be tolerated if you only drilling the occasional hole, it can become a problem with production runs of greater volume.  The reasons for this problem are two-fold:

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1)      Your using a 10mm shank bit (w/flat on shank):   Most metric drill bits have a 10mm shank with a flat area machined onto the shank (for set screw tightening).  When inserted into a 10mm collet this flat spot prevents the collet from concentrically gripping the shank all around. (see image).

Guhdo toolholder drill bit shank HSK collet

HSK 63 F Toolholder with collet and drill bit with flat spot. The collet does not grip the shank all around.

The solution: a small drill adapter (6381) that goes between the collet and the drill bit fills this space and allows the collet to concentrically grip the shank.  This adapter has a 10mm cylindrical shank (no flat) to go, which accepts the 10mm shank w/flat drill bit, tightened with a set screw as is standard on boring machines.

HSK 63 F Toolholder with standard collet and small drill bit adapter Guhdo

HSK 63 F Toolholder with standard collet and small drill bit adapter

2)      Using cylindrical shank bits (no flat on shank): Many in-between or uncommon sizes of cylindrical shank drill bits don’t fit snugly into the closest collet size available and therefore slip or chatter during the drilling process.

6380

The solution:  a Universal drill adapter (6380) which comes in two diameter ranges, infinitely adjustable within the specified range.  (accepts 1-13mm diameter drills, or 3-16mm diameter) and is available in HSK63 F, ISO/SK30 and SK40 version.  The 6380 Universal Drill Adapter has high-clamping power and accuracy, is Made in Germany, and can be run either clockwise or counter-clockwise.

For more information check out The Drill on Drill Bits or visit our website at guhdo.com!

Drills

Carbide-tipped blind-hole or through-hole dowel drills are among the most indispensable tools in the furniture industry. When used in automatic boring machines or CNC machining centers, hole edge quality and tool life are the decisive quality criteria.

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Ideal features include:

  1. Quality: Brazing and Transition from the T.C. Head to body
  2. Tolerances: Shank and clamoing flat
  3. Geometry: Negative spurs: T.C. grade and body material
  4. Coating: Thin Teflon coating

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Always purchase drills from a competent specialist dealer or the manufacturer. You will gain an economic advantage while also receiving excellent quality and having access to a person with knowledge and expertise in the subject matter. Aside from that, purchasing from a reputable company will also ensure that you always receive technically leading products as they are the first to know about tooling advances.

For more information visit guhdo.com