| Qty | Part | What it's for | ||
|---|---|---|---|---|
| Frame | ||||
 | 2 | 3030 aluminium extrusion, 250 mm | Main frame, one in front and one at the back · buy one 600 mm length and cut two 250 mm pieces · drill and tap both ends of each piece for M8 (see Build the frame) | Amazon → |
 | 4 | M8 × 20 mm socket head screws | Bolt the left and right printed end brackets to the ends of the 3030 extrusions for a sturdy frame | Amazon → |
 | 7 | M6 T-nuts for 3030 | Hold the stone holder, electronics box and accessories on the extrusion | Amazon → |
 | 7 | M6 screws | Go into the T-nuts | Amazon → |
 | 4 | Rubber feet | Optional · one under each 7.3 stand, so the machine stands steady and does not slide | Amazon → |
| Linear motion | ||||
 | 2 | 8 mm rod, 300 mm | X axis | Amazon → |
 | 2 | 8 mm rod, 150 mm | Y axis | Amazon → |
 | 1 pack | LM8UU linear bearings, 8 mm | The gliders that run on the 8 mm rods | Amazon → |
| Belt drive | ||||
 | 1 | GT2 timing belt, 6 mm | Drives the CoreXY gantry · 2 mm pitch | Amazon → |
 | 3 | GT2 pulley, 20 teeth | Two on the CoreXY motors, one on the pump motor | Amazon → |
 | 8 | GT2 idler wheels, toothless | Guide the CoreXY belt around the frame | Amazon → |
 | 2 | GT2 belt clamps | On the X sled under the tool holder, where the belt ends are fixed | Amazon → |
| Tool carriage | ||||
 | set | Springs, 5 × 25 mm | Spring-load the pressure screws that press the tool onto the stone | Amazon → |
 | — | Carbon rod, 5 mm | Guides for the spring-pressure screws and the water-pipe holder · cut to length | Amazon → |
 | 4 | Steel pins, 3 × 35 mm | Reinforce the printed screws (tool holder, drip arm) so they do not snap | Amazon → |
| 2 | Steel pins, 3 × 20 mm | Same job, in the shorter printed screws | ||
| Stone holder | ||||
 | 1 | Sharpening stone, 150 × 50 × 18 mm | The sharpening surface · clamps into the stone holder | Amazon → |
| 1 | 8 mm rod, 300 mm | Holds the stone holder in place | Amazon → |
| Water pump | ||||
 | 1 | GT2 pulley, 60 teeth | Water pump drive | Amazon → |
 | 1 | Steel rod, 5 × 60 mm | Pump drive shaft · cut to length | Amazon → |
 | 6 | Ball bearings 5 × 10 × 4 mm | Pump rollers that squeeze the tube | Amazon → |
 | — | Steel pins, 5 × 25 mm | Axles for the pump rollers | Amazon → |
 | — | Silicone tube, 3 × 6 mm | Water line through the pump to the disperser | Amazon → |
| 6 | Neodymium bar magnets N52, ½ × ¼ × ⅛" | Optional · glued into the side frame and pump frame so the pump stays docked to the machine | ||
| Fasteners | ||||
 | 8 | M3 × 18 screws | Mount the three stepper motors · one M3 assortment kit covers all M3 screws and nuts | Amazon → |
| 4 + 4 | M3 × 18 screws + nuts | Tension the timing belt | Amazon → |
| 2 + 2 | M3 × 18 screws + nuts | Hold the belt clamps | Amazon → |
 | 4 | M2 × 5 screws | Fix the PCB in the electronics box | Amazon → |
How to cut, drill and tap the 3030 extrusions: Build the frame →
| Qty | Ref | Part | What it's for | ||
|---|---|---|---|---|---|
| Modules | |||||
 | 1 | U1 | ideaspark ESP32, 1.9" ST7789 LCD | Main controller with the built-in screen · CH340 USB-C, 16 MB flash | Amazon → |
 | 3 | U2–U4 | BIGTREETECH TMC2209 V1.3 | Quiet stepper drivers: two for the gantry, one for the pump · fit the heatsinks | Amazon → |
 | 3 | M1–M3 | NEMA 17 stepper, 1.8° | Two drive the gantry, one drives the water pump | Amazon → |
 | 1 | — | LM2596 buck module | Turns 19.5 V into 5 V for the ESP32 · sits beside the board | Amazon → |
 | 1 | ENC1 | KY-040 rotary encoder + push | The control knob: turn, push, hold | Amazon → |
| Board components | |||||
 | 1 | PCB | AutoSharpener board, 65 × 80 mm, 4-layer | Carries the ESP32, drivers and all connectors | Electronics page → |
 | 3 | C2 C4 C13 | 100 µF / 50 V electrolytic, 8 × 12 mm | Motor-supply buffer, one per driver · 3.5 mm lead pitch, low ESR | Amazon → |
| 1 | C5 | 100 µF / 25 V electrolytic, 6.3 mm | Smooths the ESP32's 5 V supply · 2.5 mm pitch · from any electrolytic capacitor assortment on Amazon | ||
 | 4 | C6–C9 | 100 nF ceramic capacitor | One filters the 5 V supply, three debounce the encoder · from an assortment kit, 5 mm pitch | Amazon → |
| 1 | R1 | 1 kΩ resistor, ¼ W | Lets the ESP32 talk to all three drivers over one wire · from any resistor assortment on Amazon | ||
| 2 | R2 R3 | 10 kΩ resistor, ¼ W | Pull-ups for the two encoder signals · from any resistor assortment on Amazon | ||
 | 1 | SW1 | SS12D00 slide switch | Powers the ESP32 from the jack or from USB only · any SS12D00 on Amazon | Amazon (example) → |
 | 2 × 15 | U1 | Female header, 2.54 mm | Socket, so the ESP32 can be unplugged · cut from 1 × 40 strips | Amazon → |
| 6 × 8 | U2–U4 | Female header, 2.54 mm | Sockets, so the drivers can be unplugged · cut from 1 × 40 strips | Amazon → |
 | 3 × 4 | M1–M3 | Pin header, 2.54 mm, angled | Motor cable connectors · right-angle | Amazon → |
| 1 × 5 | ENC1 | Pin header, 2.54 mm, angled | Encoder cable connector · right-angle | Amazon → |
| Power & wiring | |||||
 | 1 | — | 19.5 V laptop charger | Powers the whole machine · any old, unused 19.5 V laptop charger (≥ 40 W) works: cut off its connector and fit the barrel plug, centre-positive. Never above 24 V. | Amazon (example) → |
 | 1 | J1 | 5.5 × 2.1 mm barrel plug + socket pigtails, 1 pair | Socket: power inlet in the electronics box · plug: replaces the PSU's original tip | Amazon → |
 | — | J1–J3 | Hook-up wire, 0.75 mm² & 22 AWG | Jack to board (0.75 mm²), board to buck converter (22 AWG) · spare pigtail wire from the barrel-jack pack works | Amazon → |
3D printer
For the 34 printed parts; the stone holder is 175 mm long.
Taps
M10 × 1.5 and M8 × 1.25, to clean up the printed threads. The M8 also threads the 3030 ends, with a 6.8 mm drill bit.
Soldering iron
Through-hole only — no SMD on the board.
Multimeter
Set the buck output and check supply polarity before connecting anything.
Saw / cutter
For the extrusion, steel rod and carbon rods.
USB hub + A-to-C cable
On a MacBook Air (M4), and likely other MacBooks, the ESP32 does not boot when plugged straight into a USB-C port. Connect it through a hub with USB-A ports and a data A-to-C cable. A hub that works: Amazon →
Drill and bits
3 mm to clean out the pin holes in the printed screws, 6.8 mm for the 3030 threads, 8 mm to clean out the rod holes in the printed brackets if a rod will not fit.
CA glue
Superglue, to fix the 7.3 stands under the end brackets.
Baking sheet optional
Stand the machine in one so the water circulates endlessly, e.g. 17 × 11 in. Example: Amazon →