Core Drill Speeds (Diamond)

Diamond Core Drill Speeds

These speeds are estimated only.  Please contact your tooling manufacturer with specific details about the material and machine running the tooling for more accurate information.

.75 – 2.5 mm1/8 to 1/2 inch5/8 to 1-1/2 inch1-3/4 to 2-3/4 inch3 to 4 inch
30,000 TO 18,000 rpm2,400 -1,000 rpm1,250 – 1,000 rpm1,100 – 850 rpm850 – 200 rpm

NOTE: Never run diamond tooling dry. Not many people realize it, but a diamond is flammable because it is essentially carbon. If you have enough heat and oxygen, it will burn the same as a lump of coal – just a bit more slowly. Drilling without proper coolant in place produces enough heat to “burn” off the tips of diamond tooling and dull or even destroy the tooling completely.

  • You should use higher volumes of coolant when the hardness of the material increases. Sparks or a dry, crumbly residue while drilling are not a good sign! These indicate too little coolant.  You need to make sure that the set-up is immediately changed. Coolant must reach the drilling area.
  • Proper use of coolant helps increase diamond drilling efficiency. It reduces heat. It lowers the chance of cracking or otherwise damaging the part being drilled or the tooling.
  • Proper use of coolant will help flush away debris. It helps guarantee proper lubrication of the drill. Often times, using an up and down motion (peck drilling) keeps fresh coolant in the proper area. AutoDrill offers a through-the-tool coolant option. There is always a fresh supply of coolant at the tool with this option.


Note that excessive tool wear or breakage is often caused by one of the following:

  • Improper surface speeds
  • Improper feed rates
  • Dull tooling or clogged tooling
  • Hard spots in the material
  • Improper coolant or lubricant type (never run diamond tooling dry!)
  • Inadequate coolant or lubricant (overall for debris removal, rubbing, etc.)
  • Inadequate coolant or lubricant (at the tip of the tooling)
  • The tool is not rigid enough
  • Too deep of a cut without proper chip removal – Chip packing (try peck drilling to get coolant down there, get debris out, etc.)
  • Tools that were manufactured or used incorrectly on previous jobs

Please CONTACT US to discuss your application and receive prompt product cost, literature and technical help.

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