SpoolBuddy Assembly Guide¶
This guide walks you through assembling the SpoolBuddy from 3D-printed parts and electronics. Follow the steps in order — each section builds on the previous one.
Download Printed Parts¶
All parts are designed for SpoolBuddy and printed in PLA or PETG. Download the full project as a single .3mf file (recommended — all parts pre-arranged for slicing) or grab individual .stl files if you only need specific pieces.
SpoolBuddy.3mf — full project (all parts)
| Part | File | Description |
|---|---|---|
| Case — Part 1 (Electronics) | case_part_1_electronics.stl | Electronics base — holds scale module, display rail guides |
| Case — Part 2 (Scale) | case_part_2_scale.stl | Scale housing — load cell channel, joins to Part 1 via dovetails |
| Case Cover | case_cover.stl | Lid for the scale housing (Case Part 2) |
| Case Back Cover | case_backcover.stl | Back cover for the main enclosure |
| Display Holder | display_holder.stl | Back bracket for the display, screws to case |
| Display Cover | display_cover.stl | Front bezel frame, clips over the display |
| NFC Reader Cover | nfc_reader_cover.stl | Cover for the PN5180 module on the spool plate underside |
| Spool Holder | spool_holder.stl | Spool plate — mounts on load cell, holds filament spool |
| Spool Stopper | spool_stopper.stl | Curved arc, clips into spool plate rim |
Parts Inventory¶
Before starting, confirm you have all printed parts:
| Part | Qty | Notes |
|---|---|---|
| Case Part 1 — Electronics | 1 | Holds scale module, has display rail guides |
| Case Part 2 — Scale | 1 | Load cell channel, dovetail joins to Part 1 |
| Case Cover | 1 | Snaps onto Case Part 2 (scale housing) |
| Case Back Cover | 1 | Closes the back of the case, shared screws with display holder |
| Display Holder | 1 | Bracket screwed into display standoffs, slides into case rails |
| Display Front Cover Frame | 1 | Beveled bezel frame, clips over the front of the display |
| Spool Plate | 1 | Multiple hole positions for adjusting distance from display |
| Spool Stopper | 1 | Curved arc, clips into spool plate cutout |
| NFC Module Cover | 1 | Clips onto spool plate underside |
Hardware Required¶
| Screw | Qty | Used for |
|---|---|---|
| M4 × 25 mm hex socket | 4 | Load cell → Case Part 2 (2), Spool plate → load cell (2) |
| M3 × 5 mm self-tapping | 2 | Display assembly → case rail lock |
Before You Print — NFC Module Cover¶
Do this before printing the NFC Module Cover
The NFC Module Cover has a circular wire exit hole on the right side. If your NFC wiring requires a larger or differently shaped cutout, use a negative body/part in your slicer to enlarge it before printing. It is much easier to do this now than to modify a finished print.
Step 1 — Join Case Part 1 and Case Part 2¶
- Align the two dovetail joints on Case Part 1 (Electronics Base) and Case Part 2 (Scale Housing)
- Slide the two parts together until they are fully seated
- No screws are required — the dovetails hold the parts together firmly
- If you want extra rigidity, a small amount of superglue can be applied to the joint, but this is usually not necessary
Step 2 — Install the Scale Module (NAU7802)¶
- Place the NAU7802 PCB onto the 4 standoffs inside Case Part 1
- Press down until the board seats on all four standoffs
- Route the NAU7802 cables through the oval cable routing hole in the case wall
Step 3 — Mount the Load Cell¶
- Lower the load cell beam into the channel in Case Part 2 from above
- Secure it with 2x M4 × 25 mm hex socket screws through the top holes
- Route the load cell wires through the oval cutout on the side wall of Case Part 2
Step 4 — Fit the Case Cover¶
- Align the Case Cover over Case Part 2 with the open gap facing the front (towards the load cell beam)
- Press down until the two rear clips snap in and hold the lid in place
- The front gap is intentional — it allows the load cell beam to pass through freely
Step 5 — Display Sub-Assembly¶
LAFVIN display standoffs
The LAFVIN 7" HDMI Touch display comes with standoffs in the box. Use these to mount the Raspberry Pi — no separate standoffs are needed.
- Mount the Raspberry Pi onto the back of the display using the included standoffs
- Connect the HDMI and USB cables between the Pi and the display
- Attach the Display Holder to the back of the display — press it onto the display standoffs
- Press the Display Front Cover Frame onto the front of the display until the retention clip engages
Step 6 — Install Display Assembly into Case¶
- Tilt the display assembly at an angle and align it with the two sliding rail guides on Case Part 1
- Slide the assembly along the rails until it is fully seated
Step 7 — Install Case Back Cover¶
- Place the Case Back Cover against the back of the case, aligning it over the display holder
- Fasten the 2x M3 × 5 mm self-tapping screws into the Case Part 1 holes to lock the display assembly in place
Step 8 — Spool Plate Sub-Assembly¶
- Mount the PN5180 NFC module into the bracket on the underside of the spool plate
- Route the NFC cables through the wire cutout in the NFC Module Cover
- Clip the NFC Module Cover onto the underside bracket — it secures with side clips, no screws needed
Step 9 — Mount the Spool Plate¶
- Choose a screw hole position on the spool plate based on how far you want it from the display
- Lower the spool plate onto the load cell, aligning the chosen hole with the load cell mounting point
- Secure with 2x M4 × 25 mm hex socket screws from the top
Step 10 — Attach the Spool Stopper¶
- Align the curved spool stopper arc with the cutout on the spool plate rim
- Press/clip it into place — no screws needed
Assembly Complete¶
Your SpoolBuddy is now fully assembled. Before powering on:
- Check all screw connections are snug
- Confirm the load cell beam moves freely through the case lid gap
- Verify NFC module cables are routed and not pinched
- Plug in the angled USB-C connector to the Pi's USB-C port — the cable exits through the cutout on the back of the case
Proceed to the Installation guide to set up the software.