CNCBridges Mini Mill Base
click images below to enlarge

Specs:
  • Swing Over - 8 5/8" with our 2" extender (included)
  • Travel / Cut Area – X = 26.5”, Y = 8.625”, Z = 9” (to the top of column)
  • Table Size – 12” x 30”
  • T-Slot Area – 10” x 24”
  • Table Slots – 4 raised casting areas to attach T-Slot surface type of your choice
  • Weight – 115lbs
  • Acme Screws – 5/8” x 8tpi x 1 start with dual ½” x 40mm x 12mm bearings
  • Lead Screw Accuracy - .003 / foot
  • Backlash Nuts – 2” Delrin with Buna-N O-Rings for compression
  • All Stainless Steel Hardware



Performance: Components used – 30v Power Supply, Applied Controllers @ 2.6a, 270oz.in. Steppers
X = 90 ipm, Y = 90 ipm, Z = 50 ipm (without offset weights or springs)

 

Materials - Made with several different Polymer / Concrete formulas depending on the application. Very strong and ridged materials with better resonance and vibration absorption than iron. Precision ACME steel screws with all Stainless Steel Hardware. 6 finger Delrin backlash nuts with dual Buna-N O-Rings for compression.

 

Z Axis - This was a lot easier than expected. I looked at several ways to attach to the head and realized you could simply replace the gib adjusters with longer bolts (pic 4) and use the gib adjuster lock nut to grab the head. Very simple. Works great. No drilling or tapping required. Mounts to column using the existing controller mounting holes. Controller mounts on back of Z movement. All mounting hardware is included.

 

Table & T-Slot Design - Our original table was 10" x 24. We increased it to 12" x 30" because it makes setup so much easier. That also provided a nice skirt for channelling fluids and swarf to the back. Our units come with the table prepared for t-slot material top of your choice.(pic 1) Includes 20 tapped and re-inforced 1/4" holes plus 20 stainless 1/4" bolts. Aluminum in the second picture is not included, that's just to show how to finish it out.

 

Table Travel X axis - 26.5" of X travel. Full left and full right shown.

 

Table Travel Y axis - 8 5/8" of Y travel. Full back and full forward shown.

 

Acme Bearing Mounts - We turn the end of the ACME screws down and then press fit, glue and pin a 3/4" stainless extension on to it. This is then turned and tapped in a lathe. We do this to get a good seat and flange for the bearings. Dual 1/2" deep groove bearings that are held together with the stainless nut. Pre-load is accomplished with a flange and four adjuster screws. This provides a completely tight mount on one end so the other end can float allowing for expansion.

 

Rails & Glides - Rails are made with 1" 6061 aluminum. We originally used aluminum for the prototypes with intentions of going to 1144tgp or Stainless 303tgp. The aluminum worked so good we stayed with it. Glides are made with a combination of Polymers and Delrin with the glide to rail surface being 90% Delrin. The Delrin is mounted in the glide frame allowing the sides to be adjsutable. There are several stainless set screws on each side of the glides to allow for adjusting tension and to remove slack when wear occurs. Glide surfaces are easily replaced in the frames if needed. If kept lubricated they will lasts for thousands of hours of production.