Kern PFB precision balance internal hardware screw size
M3 / M4 / M6 · 6 to 20 mm long
Kern PFB precision balance internal hardware takes M3, M4 and M6 metric screws in lengths from 6 to 20 mm.
There are 3 separate fitment records for it, including same service manual explicitly lists 'M3x12,8.8' and 'M3x6' and 'M3x12' fasteners in the b (M3), service manual spare-parts/exploded diagrams list explicit fastener call-outs 'M4x12, 6.8' (M4) and manual explicitly lists an 'M6x20' fastener used in the balance's internal/base assembly, (M6).
3 of the 3 records are marked confirmed, drawn from 1 source (frankshospitalworkshop.com).
For reference, M3 is 3 mm across the threads at 0.5 mm pitch. The imperial size people confuse it with: #5-40 (3.18 mm) or #4-40 — neither interchanges with M3.
Kern PFB precision balance internal hardware screw specifications
One row per fitment record. Head, drive are shown only where the source states them; pitch is the ISO coarse pitch for the thread.
| Thread | Length | Pitch | Head | Drive | Where it goes | Status |
|---|---|---|---|---|---|---|
| M3 | 6–12 mm | 0.5 mm | not stated | not stated | Same service manual explicitly lists 'M3x12,8.8' and 'M3x6' and 'M3x12' fasteners in the balance's internal assembly diagrams | Confirmed |
| M4 | 10–12 mm | 0.7 mm | not stated | not stated | Service manual spare-parts/exploded diagrams list explicit fastener call-outs 'M4x12, 6.8', 'M4x10, 6.8', 'M4x10' for internal chassis/weighing-cell mounting screws | Confirmed |
| M6 | 20 mm | 1 mm | not stated | not stated | Manual explicitly lists an 'M6x20' fastener used in the balance's internal/base assembly, alongside M4/M3 screws | Confirmed |
Fitment records and sources
Same service manual explicitly lists 'M3x12,8.8' and 'M3x6' and 'M3x12' fasteners in the balance's internal assembly diagrams
pitch 0.5 mm · tap 2.5 mm · clearance 3.4 mm · PH1 / Torx T10
Service manual spare-parts/exploded diagrams list explicit fastener call-outs 'M4x12, 6.8', 'M4x10, 6.8', 'M4x10' for internal chassis/weighing-cell mounting screws
pitch 0.7 mm · tap 3.3 mm · clearance 4.5 mm · PH2 / Torx T20
Manual explicitly lists an 'M6x20' fastener used in the balance's internal/base assembly, alongside M4/M3 screws
pitch 1 mm · tap 5 mm · clearance 6.6 mm · PH3 / Torx T30
How to check the screw before you buy
- If several screws hold the same part, check that they are all the same length before assuming they are.
- Diameter: across the threads an M3 screw measures about 3 mm with calipers (usually a hair under). This device also uses M4 / M6, so measure each screw rather than assuming they match.
- Pitch: 0.5 mm from one thread crest to the next (20 crests per centimetre). A thread pitch gauge or the pitch-gauge tool settles it in seconds.
- Length: measure from under the head to the tip for pan, button, wafer and cap heads; countersunk (flat) heads are measured overall.
- The records span 6–20 mm, which means different positions take different lengths — match each hole to its own screw.
- Driver: the source does not name the drive. Standard M3 heads take PH1 for Phillips and T10 for Torx, and a 2.5 mm hex key for socket heads; a bit that fits loosely will cam out and strip the head.
- Tightening: no device-specific torque is published in these records. The site's general figure for M3 is about 80-130 N·cm into metal threads and 35-60 N·cm into plastic bosses; snug it up and stop.
Common mix-ups with M3 / M4 / M6
- Many gas-detector and sensor manuals only give a torque spec (e.g. '0.5 N·m max') without repeating the thread size at every mention — the explicit M3 callout is usually only in the accessories/spare-parts table, not the main installation steps.
- US-made pinball machines (Williams/Bally/Stern) overwhelmingly use imperial UTS threads (#6-32, #8-32, #10-32); explicit metric threads only appear on newer/import components such as Jersey Jack Pinball's Hobbit Smaug assembly (M3).
- Astro dovetail hardware is inconsistent: Losmandy-brand dovetail plate screws are 1/4-20 (imperial) per Losmandy/Astro-Physics documentation, while PrimaLuceLab's PLUS-standard dovetails explicitly use M6 — don't assume metric across all 'Losmandy-style' dovetail ecosystems.
Buy these screws at TechSpare Warehouse
In stock and shipped from South Carolina. Our black screws are Phillips wafer head (low profile); match the head style and length to the original before you order.
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More in Other Equipment
The same screw also fits
Devices whose records share a thread with Kern PFB precision balance internal hardware, closest length match first.
- PSU internals & fan grilles also M3 × 6–8 mm
- Allen-Bradley PowerFlex 755 IP00 control pod also M4 × 12 mm
- Commodore Amiga 500/600/1200 desktop case also M3 × 6 mm
- Roces inline skate frame mounting bolt also M6 × 20 mm
- Trig Avionics TT31 Mode S transponder also M3 × 12 mm
- Wimberley AP-503 replacement foot also M3 × 6 mm
- Amiga 500 rear/front case screws (Retro32 replacement set) also M3 × 8 mm
- Navien NCO series tankless water heater also M4 × 12 mm
Questions about Kern PFB precision balance internal hardware screws
- What size screw does Kern PFB precision balance internal hardware use?
- M3 × 6–12 mm for same service manual explicitly lists 'M3x12,8.8' and 'M3x6' and 'M3x12' fasteners in the balance's internal assembly diagrams; M4 × 10–12 mm for service manual spare-parts/exploded diagrams list explicit fastener call-outs 'M4x12, 6.8', 'M4x10, 6.8', 'M4x10' for internal chassis/weighing-cell mounting screws; M6 × 20 mm for manual explicitly lists an 'M6x20' fastener used in the balance's internal/base assembly, alongside M4/M3 screws.
- How long are the screws in Kern PFB precision balance internal hardware?
- The records range from 6 to 20 mm depending on the position, so match each screw to its own hole.
- What is the thread pitch of an M3 screw?
- 0.5 mm (coarse), which is the standard pitch for M3 machine screws; a 0.35 mm fine pitch exists but is uncommon. The tap drill is 2.5 mm and the normal clearance hole is 3.4 mm.
- What screwdriver do I need for Kern PFB precision balance internal hardware?
- The sources do not name the drive. For M3, Phillips heads normally take PH1 and Torx heads T10; socket heads take a 2.5 mm hex key.
- Can I use an imperial screw instead of M3?
- No. Imperial look-alike: #5-40 (3.18 mm) or #4-40 — neither interchanges with M3. Use a true M3 screw so it does not cross-thread or strip the hole.
- Where can I buy replacement screws for Kern PFB precision balance internal hardware?
- TechSpareWarehouse (our own store) lists M3 x 6mm, M3 x 8mm and M3 x 10mm, which match lengths in the records above.