Countersink Drilling with CNC Equipment

      A custom-made one-piece step drill bit is your best bet for countersinking success. May 16, 2005

I have limited success getting good countersinks on fused melamine on MDF. I'm using various diameters with countersink attachments that screw onto fluted bits. Have varied vertical feeds (rotation 5000 rpm). Have tried CMT, Freud, even had diamond made, but they broke where cs met drill. Drilling a lot (millions) of holes.

Forum Responses
(CNC Forum)
From contributor M:
Are you drilling with a boring block (as found on some point to points and routers) or are you using the router itself to drill? Usually breakage is an excessive feed issue. If that is not the case, you could find a good local tool sharpener and have him grind you a custom drill or "drop back and punt" and use two tools, one for drilling and one for countersinking (wouldn't be quite as big an issue if using a boring block, because they could be set up to be used simultaneously).

From the original questioner:
I'm using a boring block (Biesse). Fixed spindle rotation is 5000. I've adjusted feed rate faster and slower. Boring with two separate bits takes twice as long. Boring about 12 counter sinks (and counter bores) per panel in lot sizes of 10,000 pieces, can't afford to double bore.

From contributor T:
If you are drilling millions of holes, you should look into getting custom made step drills. We went through a similar situation and it made all the difference in the world.

From contributor G:
Contributor T is correct in suggesting a custom one piece drill. We (Courmatt) have provided thousands of these tools for the wood industry. Whoever built a PCD C/S that attached it to a drill… Well, I won't comment. The drills can be made with a thru-bore, brad point, with a countersink or counterbore.

From contributor C:
If the drills are breaking where the countersink and drill come together, it will normally mean that the chips are clogging up in the gullet of the countersink. This can be eliminated by lining up the flutes of the drill with the gash/gullet of the countersink. You can also pull the center drill out to the transition of the flute towards the shank and again line this up with the gash/gullet of the countersink. Max RPM 1750. Using carbide tipped countersinks will help.

From contributor H:
We (Southeast Tool) have had many of the one piece countersinks and counterbores special built for our customers. Most if not all metric boring bits are made overseas now. This will be your only problem (time). I am not aware of anyone that actually builds these here in the US.

Would you like to add information to this article?
Interested in writing or submitting an article?
Have a question about this article?

Have you reviewed the related Knowledge Base areas below?
  • KnowledgeBase: Knowledge Base

  • KnowledgeBase: Computerization

  • KnowledgeBase: Computerization: CNC Machinery and Techniques

    Would you like to add information to this article? ... Click Here

    If you have a question regarding a Knowledge Base article, your best chance at uncovering an answer is to search the entire Knowledge Base for related articles or to post your question at the appropriate WOODWEB Forum. Before posting your message, be sure to
    review our Forum Guidelines.

    Questions entered in the Knowledge Base Article comment form will not generate responses! A list of WOODWEB Forums can be found at WOODWEB's Site Map.

    When you post your question at the Forum, be sure to include references to the Knowledge Base article that inspired your question. The more information you provide with your question, the better your chances are of receiving responses.

    Return to beginning of article.

    Refer a Friend || Read This Important Information || Site Map || Privacy Policy || Site User Agreement

    Letters, questions or comments? E-Mail us and let us know what you think. Be sure to review our Frequently Asked Questions page.

    Contact us to discuss advertising or to report problems with this site.

    To report a problem, send an e-mail to our Webmaster

    Copyright © 1996-2019 - WOODWEB ® Inc.
    All rights reserved. No part of this publication may be reproduced in any manner without permission of the Editor.
    Review WOODWEB's Copyright Policy.

    The editors, writers, and staff at WOODWEB try to promote safe practices. What is safe for one woodworker under certain conditions may not be safe for others in different circumstances. Readers should undertake the use of materials and methods discussed at WOODWEB after considerate evaluation, and at their own risk.

    WOODWEB, Inc.
    335 Bedell Road
    Montrose, PA 18801

    Contact WOODWEB

  • WOODWEB - the leading resource for professional woodworkers

      Home » Knowledge Base » Knowledge Base Article