The following is a detailed list of specialty parts required to build the standard version of the ShapeOko cnc mill. Some parts such as nuts, socket head cap screws, washers, and wires are commodity parts found in most hardware/home improvement stores (please see the list under Additional / Commodity Items on the Purchasing page). Other parts, such as stepper motors, stepper drivers, power supplies, or microcontrollers are less likely to be found in a local store, and will probably have to order from the online suppliers. Other parts, such as the front and back frame end plates and the motor mount plates were designed specifically for this project and are custom manufactured.
Part availability and clarity are two focuses of the ShapeOko project. This page is your resource to find the descriptions and discussion links for each part you will need in order to build a ShapeOko mill. Please see the Purchasing page for a list of vendors, and where possible, direct purchase links.
ShapeOko Assemblers Pack
Many of the parts are available in the ShapeOko Assemblers Pack.
3D Model: GitHub
|0.25" Spacer||5/16" OD, 0.192" ID||Hardware store, Specialty Hardware Store, Specialty Vendors||4||The important thing is the overall dimension. In older ShapeOko kits, where 4 x 0.125" spacers were used, newer kits replace them with 2 x 0.25" spacers. An additional 4 x .25" spacers are also included for use with the smooth idlers. One can increase a machine's rigidity by using metal spacers instead. By specification, #10 bore spacers are slightly too small, but can often be used, #12 of course will fit w/ room to spare. Available from Inventables (#25312-03 or 25312-13) AluminumSpacers.com (Machinest.com) 3/8 OD x .219 ID x 1/4 Long
|0.75" Spacer||3/8" OD, 0.192" ID||Hardware store, Specialty Hardware Store, Specialty Vendors||10||When being used with M3 screws, a 7/32" roll pin is an inexpensive alternative.
|5mm Washer||10mm OD, 5.3mm ID||Hardware store, Specialty Hardware Store, Specialty Vendors||103||Four were used in the original method of belt anchoring, an additional eight were used to stand the motor off from the older mount plate design. Additional washers may be needed to adjust spacing (a stack is useful as a stand-in for a 1/4" spacer), to fasten the machine to the base, &c.|
|3mm Washer||Hardware store, Specialty Hardware Store, Specialty Vendors||11|
|5mm Nut||8mm Wrench, 4mm Thick||Hardware store, Specialty Hardware Store, Specialty Vendors||20||An additional four nuts were used to mount the belts in the original design. See Belt Anchors for an alternative.|
|8mm Jam Nut||13mm Wrench, 4mm Thick||Hardware store, Specialty Hardware Store, Specialty Vendors||2|
|Insertion Nut||M5 Size||Hardware store, Specialty Hardware Store, Specialty Vendors||8||An additional four nuts were used to mount the belts in the original design. See Belt Anchors for an alternative.|
|Screws / Bolts|
|M3 x 50mm socket head cap screw||2.5mm Hex Key||Hardware store, Specialty Hardware Store, Specialty Vendors||3||Note: You might need more M3 screws, depending upon the motors you purchase. NEMA 17 motors attach with M3 screws. NEMA 23 motors attach with M5 screws.|
|M5 x 10mm socket head cap screw||4mm Hex Key||Hardware store, Specialty Hardware Store, Specialty Vendors||22||Originally, an 8mm screw was specified (and is pictured), since, this has been changed to 10mm. Larger machines may benefit from longer lengths. (quantity was 16, why?)|
|M5 x 30mm socket head cap screw||4mm Hex Key||Hardware store, Specialty Hardware Store, Specialty Vendors||16||When used w/o an eccentric spacer, this is too long --- a 22mm (or even 20mm) bolt makes up that difference. (quantity was 24, why?)|
|M5 x 55mm socket head cap screw||4mm Hex Key||Hardware store, Specialty Hardware Store, Specialty Vendors||8||(quantity was 4, why?)|
|M5 x 16mm socket head cap screw||4mm Hex Key||Hardware store, Specialty Hardware Store, Specialty Vendors||2|
|8mm Threaded Rod||200mm Long||Hardware store, Specialty Hardware Store, Specialty Vendors||1|
|Z-Axis Coupler||5mm to 8mm Coupler||Specialty Vendors||1|
|Stepper Motor||58 oz-in, Nema 17||Specialty Vendors, Electronics Suppliers||3||CAD Data
The Shapeoko can use NEMA 17 or NEMA 23 stepper motors. The 58 oz-in motors listed are sufficient to drive the Shapeoko, but larger motors can be used. Forum Discussion.
From the forum thread Re: What Causes Z-axis Motor to Skip Steps?
Here are the physics of stepper motors in great detail:
The steppers have a torque curve that diminishes with speed, for several reasons. The nature of the construction is that the coils exhibit inductance and reactance.
The inductance sets the rate at which the magnetic fields can be saturated with flux. At high speeds the fields don't have enough time to fully saturate. This is compounded when changing directions like your z moves in 3d as the fields have to each load up and unload twice when reversing polarity.
The inductive reactance of the motors affect the driver as speed increases. At low speeds they are driven with current, but as speeds increase they are driven with voltage Instead of current and the driver introduces a phase lag. A 180 degree phase lag driven over unity is the textbook definition of an oscillator. When the motor oscillates and approaches its mechanical resonance it will start growling or buzzing just before it stalls.
The point in the torque curve where constant torque changes to inverse torque with speed is called the mid band resonance. It is also the point wher the driver switches from current to voltage. Resonance also occurs at low speed but is usually minimized with micro-stepping. It also occurs in harmonics of the resonant frequency.
To maximize torque and speed you need to drive the steppers with the highest voltage power supply that your driver can use. The mxl belts help to mechanically dampen the resonance in the Shapeoko design. And IC's Z axis upgrade would be an improvement in several ways.
Every stepper and driver system is going to have limits in feed rate settings before stalling, and the real trick is to find the balance between speed and torque allowing for deeper tool moves at lower speeds, or shallow tool depth with higher feed rates. And taking into account the inertia of the axis and tooling mass with regards to acceleration.
|E2||Power Supply||24V 4.2A||Specialty Vendors, Electronics Suppliers||1||The size of the power supply should be at least 4.2A at 24V. A larger supply (for example, a 4.5A) will work fine. The size is based on the requirements of the stepper motors you choose. Power Supply|
|E3||Stepper Driver||Pololu A4988 compatible||Specialty Vendors||3||The stepper drivers that the Shapeoko is designed to use is the Pololu A4988. There are other drivers that are compatible, including the Pololu-compatible open source Stepstick.|
|E4||Arduino (328P Compatible)||Specialty Vendors||1||Any Arduino 328P compatible board should work. Multiple vendors sell these boards, and price varies by vendor and features. Alternately the machine can be directly controlled by a computer, see Alternative Electronics.|
|E5||Arduino stepper shield|| 2.7 in x 2.1 in
(standard Uno shield size)
|Electronics Suppliers||1||The Shapeoko was designed to use the Pololu stepper drivers, and this Arduino shield makes assembly and wiring very easy and straight forward. Another option is to create your own board. A good example of this is User:DrRob, who has made his own shield using perfboard. Alternately, one could use a custom board which incorporates both an Arduino and a stepper shield such as the AtomCNC (97.8mm x 95.5mm (inches: 3.85" x 3.76")), which was available at http://atomsofttech.com/AtomWiki |
Alternate controller: Arduino grblShield
Discussion in the forums: Buildlog.net Arduino Compatible Stepper Shields available Full Controller Buildlog Stepper Shields
|Dual Bearing V Wheel||Specialty Vendors||16||
Note that there is a 1mm precision washer which goes in-between the two bearings. The specification for this part allows a bit of variance in the sizing. Forum discussions: Re: ACME screw upgrade for Shapeoko Z-Axis, and also see V-Wheel Precision Washer upgrade for your exacting CNC setup which includes a link to purchase them: Reactive Substance Storefront
|Eccentric Spacer||Specialty Vendors||8||
|Smooth Idler Drum||Specialty Vendors||4||
|MXL Belt||Specialty Hardware Stores, Specialty Vendors||4 ft||0.08" MXL, Width: .25" - Spec Sheet (PDF)|
|Belt anchor||Hardware Stores, Specialty Hardware Stores, Specialty Vendors||4||Mending brackets / plates usually sold in packs of 2 --- a Stanley Hardware Mending Bracket|
|18 Tooth MXL Timing Pulley w/ 5mm bore||Specialty Hardware Stores, Specialty Vendors||2||Pulley has 18 teeth|
608ZZ Bearing 8x22x7
Shielded Miniature Ball Bearing
|Specialty Hardware Stores, Specialty Vendors||1|
|Z-Axis Delrin Lead Nut||Specialty Vendors||1||CAD file on github
There have been a number of machines which have had issues w/ the Z-axis nut. One solution is of course an ACME Z-axis. Forum user ejs decided on directly addressing the part itself in A new Z-axis nut - metal on metal w/ built in anti-backlash.
|Makerslide Extrusion - 375mm||Inventables kit||3||Note: Tap for M5 screw, in 10mm and 16mm (or longer) lengths. See assembly instructions for details.
|Makerslide Extrusion - 200mm||Inventables kit||1||Note: Tap for 16mm M5 screw, accounting for thickness of Z-axis motor mount plate. See assembly instructions for details.|
|Standard Carriage Plate||Inventables kit||1||
|Mount Plate||Inventables kit||3||Needs to be a minimum of .0747" (~2mm) thick if made of steel . Further discussion. 1/4" noted as being “overkill”. The eShapeOko uses 2mm stainless steel (forum post on this and theorization about 3.175mm aluminum being enough in Re: New new end plates).
|End Plates (Front/Back Plate)||Inventables kit||2||SMS002 - Needs to be a minimum of .1345" (~3.5mm) thick if made of steel . Further discussion. An alternative is to use the new Open End Plates and a rectangular aluminum extrusion.
|Z-Axis Mount Plate||Inventables kit||1||CAD files on Github|
|Spindle||Amazon||1||Edward R. Ford made some notes on spindle options.|
|Spindle Mount (top)||Inventables kit or Mcmaster||1||In newer kits, the spindle mounts are milled blocks of aluminum, see Re: Insertion nut screw shaft too large for makerslide.
|Spindle Mount (bottom)||Inventables kit or Mcmaster||1||In newer kits, the spindle mounts are milled blocks of aluminum.