Using Boring Tools with a CNC Router Collet

      Boring tools can be adapted to a CNC router for use at slower RPMs. October 3, 2007

I have a couple of very basic questions regarding tooling for a CNC router. The 5mm brad point bits I've seen all have a flat on the shank. Our machine does not have a boring unit, so can these bits be used in the router? Will the flat cause problems with the collet? Will it cause vibration? What rpm and plunge rate should be used?

The tool holders on the router accept tools with shanks up to .625 inches. Is there a source for bits for MDF routed raised panel doors that have a shank diameter less than .75in?

We (2 man shop) have been using a used Multicam 3000 for a couple of months now, and in spite of the learning flubs, are very happy with it.

Forum Responses
(CNC Forum)
From contributor F:
I also have a 3000 on which I use Vortex tooling. I have used them because of their knowledge and because they have very good tooling. You are better off using just one tool company, rather than shopping around for price, because of the help they can give you.

From contributor C:
I believe most boring tools have flats, and require an adapter to be used in a typical collet. The one I use has a 10mm shank on it, thus requiring a 10mm collet. But you can then use any readily available (i.e. cheap) boring drill. I personally use Courmatt; they have been great, but any of the guys that post on WOODWEB should be able to set you up.

As far as the tool shank diameter, it sounds like you have a small spindle (up to 7.5 HP), which only allows use of an ER25 collet. The ER25 collets only go to .625 diameter, because that is as large as the machine that holds the collet is intended to run. To use .75 shank or larger, you need ER32 collets, which typically are found on larger 10HP+ spindles with larger shafts to accommodate a larger shank.

That said, you can have the shank turned down on a tool if you must, but don't go any further than you have to. My fly cutter was turned down from .75 to .625, and I've had a .75 ball-end turned down as well. Most people don't recommend this; bits that require large shanks are going to put more stress on your spindle than it is intended/designed to take, and can lead to premature failure, as well as being unsafe. The bigger spindles not only make more HP, they have sturdier frames and larger bearings, often with air assisted holding to keep things steady on a big cut.

So, if you must turn a tool down, make sure you take light passes with it or reduce your feed rate as far as you can. In MDF, this is a pain, as you probably need to slow down past the point where ignition occurs, and fire in a wood shop is no fun.

From contributor G:
You have an ER25 collect system. Use a 10mm collet. The flat will not affect any balance issues, as you need to slow your rpm's to 3600, with a plunge rate of 75IPM. Any custom tool can be made with a .625 shank, depending on the diameter.

From contributor H:
If you use the correct adapter, the balance should not be a problem. Yes, we [Southeast Tool] have MDF bits with a 1/2" shank. Most of the others are correct; 3000 to 3600 IPM is what most will run correctly at.

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 © 1996-2016 - 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