The finished mill has a 11" x 18" footprint and is about 19" tall. Depending on the motor used it is capable of machining plastic, wax, wood and non ferrous metals. Right now my motor is a bit underpowered due to the power supply I had on hand. It's very quiet- I could use this inside the house at night and not wake up the little ones!
The X axis travel is 6 1/8"
The Y axis travel is 6 1/4"
The Z axis travel is 2 1/4"
If there are any questions about any of the drawings or something just doesn't make sense just ask! You can download larger images so the drawings will be much easier to read- just click on the "i" symbol in the upper left corner. I just added an exploded view sketch that helps show how all the parts fit together.
Follow along and build one for yourself!
Step 1: Tools and materials
table saw (a miter saw would also work -they tend to be more accurate for precise cuts)
router w/ 1/2" straight cutter- needs to be mounted in a router table
jigsaw (or band saw if you're lucky enough to have access to one)
assorted files (for cleaning up rough edges)
tap and tap handle ( I used a 4mm x .7 tap because I used metric screws but you could also use an 8-32 tap if you want to use 8-32 screws)
#10 countersink bit
1 1/4" Forstner bit
5/16" Forstner bit (used for counterbores for 4mm bolts)
3/4" thick Birch plywood was used for the following pieces-
11" x 18" -base plate
12" x 4" -Y axis base plate
8" x 4" -Z axis base plate
6" x 2 3/4" - motor mount base
12" x 9" (make four of these) -for the mill column
2 1/2" x 1 7/8" (make three of these) -for the anti backlash screw blocks
3/4" thick MDF (medium density fiberboard) was used for the following pieces-
6" x 6"- mill table
3 7/8" x 1" (make six of these) -rail end blocks
Aluminum channel- 57/64" x 9/16" x 1/16" wall thickness:
12" long (make four) -X and Y axis rails
8" long (make two) -Z axis rails
3/8" thick Delrin was used for the following pieces (Delrin can be purchased from Colorado Plastics):
4" x 3 7/8" (make three of these) -slides
2 1/2" x 3/4" (make three of these) - handles
3 1/2" x 3/4" (make six of these) -slide retainers
5/16" round Aluminum rod:
1 1/2" long (make three) -handles
1/4" round Aluminum rod:
3/4" long (make six) -inserts for anti backlash blocks
1/4"-16 ACME threaded rod: available from McMaster-Carr part#98935A803
12 3/4" long (make two) -X and Y axis lead screws
8 3/4" long -Z axis lead screw
6 each 1/4"-16 ACME nuts -for anti backlash screw blocks (McMaster part#94815A007)
3 each 1/2" diameter 1 1/4" long compression spring -for anti backlash screw blocks
3 each 1/4" locking collars -these help hold the ACME screw rod in place (McMaster part# 6432K12)
6 each 1/4" bronze flanged bushings (these fit a 1/4" shaft and fit into a 3/8" bore) -for the rail end blocks (McMaster part#6338K451)
3 each 1/4" washers (just about any thickness will do) -these are spacers for the handles
3/4" wide Aluminum or brass plate (1/16" thick):
1 7/8" long (make three) -for anti backlash ACME screw retaining plates
1 3/4" (45mm) long bolts w/ washers and nuts:
12 each- I used 4mm hex head bolts for all the bolts but 8-32 bolts will also work
-these go on the ends of the Aluminum channel rails
1" (25mm) long bolts w/ washers and nuts:
4 each- 4mm
-these go in the middle position of the x and Z axis Aluminum channel rails
3/4" (20mm) long bolts:
38 each- 4mm
6 each 4mm x 1/4" (7mm) long set screws -for the handles
8 each 2" long wood screws -for securing the mill column to the base plate and the Z axis base plate
1/2" diameter wood dowel:
4 each 3" long -inserts for mill column
6 each 3/4" long -inserts for rail end blocks
For the motor assembly/spindle I used a 12v electric motor salvaged form my junk box along with a Foredom #44 handpiece. The #44 uses 1/16", 3/32", 1/8" and 1/4" collets (it's also available in metric) so it fits a wide variety of cutting tools. I also have a #30 handpiece which has a standard drill chuck. Both are extremely durable and are very quiet. You could also use a standard Dremel tool if you want an all in one solution.
For the CNC conversion:
6 each 2 1/2" x 2/12" x 3/4" thick Birch plywood pieces -for stepper motor mounts
3 each stepper motors
3 each motor couplers -I made mine myself from old parts I got from a display but the ones I've linked to are identical
12 each #10 1" long wood screws
6 each #10 2" long wood screws
7/8" Forstner bit
CNC stepper motor controller- the HobbyCNC or Linistepper would be my choice
Some notes about using a router table and drilling holes for screws:
When using a router table you always want to cut in a certain direction- the cutting bit should try to force your work into the fence (see drawing.) If you move your work in the opposite direction, the bit will pull your work away from the fence and it will be difficult to get a precise cut.
On many of the drawings I specify a countersink or a counterbore. A counterbore has a flat bottom (it's best cut with a Forstner bit or end mill) and is meant for flat bottomed screws. A countersink is for flush mounting screws with a tapered head, like most wood screws. The other important thing is to always drill a pilot hole first, then a clearance hole and then the counterbore or countersink. If you don't drill a proper clearance hole, the screw will try separate the two parts you're trying to screw together. It'll also make it difficult when cutting threads for machine screws- see the drawing below.
Please use care and good judgment when operating power tools. Always keep fingers well away from cutting tools- use a push stick for cutting thin stock on a table saw and router table. Always wear eye and ear protection and a dust mask- especially when cutting MDF as the dust it produces is pretty nasty stuff.