I have a small CNC that I built awhile back.  Its a larger version of my KReduCNC. Some of the parts were lasercut and machined plastic parts.  If a particular component worked out, I would convert it to steel or aluminum as needed.

Today I am going to replace the Z motor and bearing mounts. The parts will be machined from 3/8" 6061 Aluminum.

The bit

I have been playing with the Whiteside RU2100 spiral router bit, and felt that making these parts would let me test the bit further.

 

Making the Parts

See more at www.kronosrobotics.com

 

Problems Encountered

Originally  I wanted to machine the .26" diameter mounting holes with the bit, but this did not work.  The bit does not cut all the way to the center so cutting a hole that small was impossible.  Luckily I was able to stop the job before breaking the bit ruining the part. (See Working with Aluminum #11)

In addition, I was getting some chatter marks on the finish cuts.  I have had much better results with other bits cutting this deep.  

 

Holes

I drilled out the divots with a 1/4" drill bit on my drill press.  This was easy with the divots acting as a guide.  In addition to the mounting holes, I added two small holes in the sides and tapped them for a #6-32 machine screw.  This would allow me to secure the plates to the steel shafts on the machine. 

 

Conclusion

I was very happy with the parts, but will be looking at some other spiral bits that will allow me to machine small through holes.

I discovered a few other things with this little project.

  1. The large amount of chips created were not contained very well with my Swarf Shield. I had to clamp some extra pieces to the sides to keep the chips from getting into my electronics.  This was a temporary fix at best.  I will have to revisit the shield for use with larger bits.
  2. I do not like the KoolMist misting system.  It is not very consistent, unless its on full blast, and that is just not how I use it.  I will be looking into my own drip system a little later.