I found these two bits at Lowes and decided to test them both for milling. Both are 1/8" Rotozip bits that will fit in the Dremel tool.  My plan is to mill the parts for an acrylic body plastic extruder.

Test Results

Using the Sabercut Bit, I did my first milling experiment.  I started at the lowest speed on the dremel (5000 rpm) but moved up to the highest setting by the end (25000 rpm) of the run. I had a few problems with geometry due to the flex in the mount holding the dremel and the flex in the bit itself. Overall I was pretty happy with this first run-but next time I will do a better job setting the Z-height so I don't run the mill into the base plate again. Below are photos and a video of the mill in action.

I used a feed rate in the gcode of F75. Next time I think I will try a little slower and keep the rpm high on the dremel to start with.

More pictures below...

• Add New

Comments (9)

• 2009-05-12 06:04:24 | Phil Waud  - Flex issue
  Nice rig, Im building a similar set up, and will also be using a Dremel to mill (at least at first) From the video, it seems to me that the issue is not so much the rig flexing, but the actual bit itself bending. When you use a conventional miller to mill metal etc, the bit is normally quite substantial and very short (stocky is probably the word) Are there bits for the Dremel available like that? Can you use a very short drill bit?
  Reply

• 2010-01-08 20:45:06 | Bruce
  A better candidate for this is a Harbor Freight laminate trimmer. A bit heavier, but uses 1/4 or 1/8 bits, better strength and stronger motor.
  Reply

• 2010-01-08 21:13:02 | Jeff
  I'll definatly have to check that out.
  Reply

• 2010-01-09 10:59:46 | Bruce  - Laminate Router
  Additionally, it is low cost - on sale for 19-24 $ US; I built a CNC for Wood/plastic.light Aluminum, this works very well..... I expect now to try to adapt that CNC to also do rep rap, viewing your extruder info with interest in how I can build one, and adapt to my Mach3 environment on either the wood CNC or my HF mill which I have turned into a CNC machine as well.
  Reply

• 2009-05-12 06:10:14 | Jeff
  I could probably find a shorter bit, now that you mention it the one I am using is quite long. The geometry did get better when I raised the RPMs, I think it was sticking when it was going slow. These bits were for a rotozip, so the flex/inaccuracy is OK for the intended application, and I at $0.75 each they were hard to pass up. I think the Dremel brand has some similar bits that are shorter and higher priced at local hardware stores.
  Reply

• 2009-11-14 15:48:15 | vittore  - Which software for milling?
  Very interesting! I'm trying the same. Which software do you use to send Gcode to machine? replicatorG? thanks in advance v.
  Reply

• 2009-11-17 19:22:00 | Jeff
  I used ReplicatorG and CamBam to make the gcode.
  Reply

• 2010-01-13 13:05:53 | John Wasser  - RotoZip bits are for down-cuts
  One big problem with using RotoZip bits for milling is that they push material toward the tip. This works fine when cutting sheet goods (plywood, acrylic, plasterboard, fiberboard) when there is no backing but will cause problems in milling on a platform or making blind holes. McMaster.com has a bunch of 1/8" shank solid carbide end mills for under $10 each.
  Reply

• 2010-01-14 21:30:50 | Jeff
  Thanks for the tip, I'll keep that in mind next time I try some milling.
  Reply

Write comment

Your Contact Details:

Name:

Email: do not notifynotify

Comment:

Title:

Message:

Security

Please input the anti-spam code that you can read in the image.

Joomla components by Compojoom