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I decided to try to find out what the reasonable minimum that this machine could be built for was.  I used all the proper parts for the machine described in the book... no shortcuts or upgrades.  However, I made a fair effort to find better pricing for everything.  The result should realistically answer the question of just how much it costs to enter the CNC playground.

[contentheading]What you'll need[/contentheading]

  • Tools:  This build requires some specific or specialized tools to complete.  I am actually a bit disappointed that a non-trivial portion of the build price can be attributed to needing a few tools that can be expensive.  I would like to see an improved design that may find a way to eliminate the need for some of them.
    • Self-Centering Doweling Jig:  Optional, but makes drilling holes for cross dowels in the edges of boards much easier.
    • Heavy Duty Laminate / Trim Router:  For the machine to use itself, you'll want a laminate router with about 1HP.  Laminate routers rated as 6-8 Amp are typically in this range.  You'll also need the router to chamfer the board edges to accept aluminum angle rails.
    • 45-Degree Chamfer Router Bit:  Needed for exactly 12 edges of the machine.  It's a shame they cost so much, and nobody I knew that owned a router had one.
    • Power Drill:  You're going to need a power drill.  Either 3/8" or 1/2" chuck would work.
    • Power Drill Guide:  People may remember these made by Portalign, but something similar is now marketed as the Craftsman Drill Guide.  It turns your power drill into a mini drill press, and is a lifesaver for making straight holes.
    • Drill Press:  Completely optional, but will save you tons of time, and improve the quality of your work.
    • Drill Bits, Forstner Bits: You'll need a variety of drill bits for this project.  For most of them, they must be twist drills, paddle bits, or forstner bits, because they are used for counterboring and do not go all the way through the wood.  A couple of the holes, such as the 2-1/4" hole for the vacuum hose, do pass all the way through and could be made by a hole saw.  Some of them, like the 1-1/8" Forstner bit to drill the pockets for the 1/2" bearings, are odd sizes, and will most likely need to be purchased alone (because they tend not to come in kits).  The sizes of bits you need include: 1/16", 1/8", 1/4", 5/16", 1/2", 5/8", 3/4", 7/16", 1", 1-1/8", 1-1/2", 2-1/4"
    • 5/16" Tap Set:  For tapping holes in the aluminum angle to make the bearing trucks.  It's easiest to get the kind that includes the appropriate drill bit.
  • Parts / Hardware
    • Cross Dowels - 1/4" 20 TPI
    • Roller skate bearings - 8x22x7mm:  Incorrectly referred to in the book as 5/16"x7/8"x1/4"
    • 1/2" ID bearings for lead screws - 1/2"x1-1/8"x5/16"
    • 1/4"-20TPI bolts in various lengths 1"-3"
    • 1/4"-20TPI nuts
    • 5/16" bolts, 3/4" long
    • 5/16" nuts
    • #8 screws
    • #8 nuts
    • 1/2"-13 square nuts - 3 total (one for each axis)
    • 1/2"-13 threaded rod - 10' total
    • 3/4" aluminum angle, 1/8" thick
    • 1-1/4" aluminum angle, 1/8" thick
    • 18ga Stranded Wire:  You need about 50' each of 4 colors.  You can get 4-conductor wire, often called "Security Wire", and just strip the insulation to get the 4 colors out.  Don't get solid core wire.
    • 1/4" to 1/2" couplers - 3 total (one for each axis)
    • 4'x8'x3/4" sheet Medium Density Fiberboard (MDF) - Have them cut it into 4 pieces 2'x4'.  2 pieces need to be as similar as possible.
  • Electronics / Computer
    • Computer, Keyboard, Mouse, Monitor:  It doesn't need to be real powerful.  If you know someone that has replaced their PC recently, see if you can have their old one.  If you need to buy one, there are websites that deal in used/older models, such as Geeks.
    • Stepper motors, 1/4" shaft, 425oz/in
    • Stepper motor drivers
    • Breakout board and power supply
    • Power suppy
    • DB25 Male-to-Male Straight Through Cable

[contentheading]How my costs broke down[/contentheading]

Harbor Freight (Retail Store)

Home Depot (Retail Store)

  • 4'x8' sheet of 3/4" MDF (cut for free into 4x 2'x4' pieces at panel saw): $28.22
  • 5/16"x3/4"L Hex Bolts: 26 x $0.15 = $3.90
  • 1/2" Square Nut: 3 x $0.50 = $1.50
  • + $2.35 Tax = $35.97 Total

Lowes (Retail Store)

  • 18g/4-conductor Security Wire: 50' x $0.50 = $25.00
  • + $2.01 Tax = $27.01 Total

Murdoch's Ranch & Home (Retail Store)

  • Bulk Grade 2 Nuts and Bolts (this takes care of most of the bolts needed): 6.09lb x $1.49/lb = $9.07
  • #8 Phillips 2" machine screws: 14 x $0.22 = $3.08
  • #8 nuts: 40 x $0.08 = $3.20
  • + $1.24 Tax = $16.59 Total

VXB Bearings (Online Store)

  • 608ZZ 8mmx22mmx7mm (incorrectly referred to in the book as 5/16"x7/8"x1/4"): 3 x $3.95 per 8-pack = $11.85
  • R8ZZ 1/2"x1-1/8"x5/16" (cheaper in 10-pack, but only 6 are needed): $19.95 per 10-pack
  • + $4.99 Shipping = $36.79 Total

Rockler (Online Store)

Rockler (Online Store)

  • 1/4"x20TPI Cross Dowels (on sale):  7 x $1.89 per 8-pack = $13.23
  • + $6.95 Shipping + $0.59 Tax = $20.77 Total

Harbor Freight (Online Store)

  • 45-degree Chamfer 1/4"-shaft Router Bit (I bought 3 since they were $1): 3 x $0.97 = $2.91
  • + $6.99 = $9.90 Total

Amazon (Online Store)

  • Incra T-RULE06 6-Inch Precision Marking T-Rule: $17.95
  • Incra MTG-0302 3"x2-1/32" Pocket Rule: $7.16
  • Milwaukee 48-14-1125 1-1/8" x 3/8" Shank Forstner Bit: $9.99
  • + Free Shipping (>$25) = $35.10 Total

Cutting Tool Source (Online Store)

Grainger (Retail Store)

Directron (Online Store)

Automation Direct (Online Store)

 

Total: $478.47