Loaded CNC router bit question.

[Clark Pace]

Ok, I just finished my first DIY CNC. I'm newbie to router bits though.

I cut mainly acrylic and mdf wood. I can hold 1/4"(6mm) bit. Suggestions for my first cnc bits to buy. I want to make signs with a v groove bit, but my main thing is cutting out speaker boxes. So lots of round holes. Any suggestions would be appreciated.

P.S. I am currently using a down spiral 1/8" bit that I borrowed to test the mahine out.

[John McClanahan]

I would suggest using average priced bits to learn on. That way if bad G-code causes damaged bits, you won't waste as much money.

John

[Richard Coers]

Don't use the same bit for mdf and acrylic. Keep bits for each. I prefer Onsrud O flute for acrylic. Anyones bit for MDF. I'm no fan of downcut spirals, and with an 1/8", the feed rates are going to be slow. I prefer 3/8" diameter myself, you can make way better speed with it. Learn how to calculate chip load, so you can set feeds and speeds.

[Mike Heidrick]

BE careful drilling holes in MDF with a downcut spiral. You will create tiny little fire holes.

[Paul Phillips]

Don't use the same bit for mdf and acrylic. Keep bits for each. I prefer Onsrud O flute for acrylic. Anyones bit for MDF. I'm no fan of downcut spirals, and with an 1/8", the feed rates are going to be slow. I prefer 3/8" diameter myself, you can make way better speed with it. Learn how to calculate chip load, so you can set feeds and speeds.

Definitely agree, and I haven't found anything better than Onsrud. Any carbide tipped wood working bit will be fine for the V-bit, also, if you are cutting shapes that you want to round-over the edges on, you can take a regular round-over bit for wood and grind off the bearing stud and set it up in your tool definition as a .5" End Mill and use your CNC to do all the round-over edges on your piece, works great.
Paul