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Power tool battery pack shell screw size

M4 · 12 to 20 mm long

The screws used on Power tool battery pack shell are M4 in lengths from 12 to 20 mm.

Where it is used: the case around the cells.

This entry is marked reported and comes from ifixit.com.

An M4 screw is 4 mm in diameter with a 0.7 mm pitch, tapped with a 3.3 mm drill; imperial look-alike: #8-32 (4.17 mm) — the standard US PC/rack screw, close but not the same.

Power tool battery pack shell 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.

ThreadLengthPitchHeadDriveWhere it goesStatus
M412–20 mm0.7 mmnot statednot statedthe case around the cellsReported

Fitment records and sources

M412-20mmreported

the case around the cells

pitch 0.7 mm · tap 3.3 mm · clearance 4.5 mm · PH2 / Torx T20

How to check the screw before you buy

  1. Industrial parts lists usually give the full callout (thread, length, head, grade); match all four, not just the thread.
  2. Diameter: across the threads an M4 screw measures about 4 mm with calipers (usually a hair under). If yours measures noticeably more or less, it is a different thread.
  3. Pitch: 0.7 mm from one thread crest to the next (14.29 crests per centimetre). A thread pitch gauge or the pitch-gauge tool settles it in seconds.
  4. Length: measure from under the head to the tip for pan, button, wafer and cap heads; countersunk (flat) heads are measured overall.
  5. The records span 12–20 mm, which means different positions take different lengths — match each hole to its own screw.
  6. Driver: the source does not name the drive. Standard M4 heads take PH2 for Phillips and T20 for Torx, and a 3 mm hex key for socket heads; a bit that fits loosely will cam out and strip the head.
  7. Tightening: no device-specific torque is published in these records. The site's general figure for M4 is about 2.0-3.0 N·m into metal threads and 0.8-1.4 N·m into plastic bosses; snug it up and stop.

Common mix-ups with M4

  • M4 and 6-32 UNC share a nominal diameter with different pitch — a classic cross-thread in US-market kits.

Pitch gauge · Screw size finder · Torque guide

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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The same screw also fits

Devices whose records share a thread with Power tool battery pack shell, closest length match first.

Questions about Power tool battery pack shell screws

What size screw does Power tool battery pack shell use?
M4 × 12–20 mm for the case around the cells.
How long are the screws in Power tool battery pack shell?
The records range from 12 to 20 mm depending on the position, so match each screw to its own hole.
What is the thread pitch of an M4 screw?
0.7 mm (coarse), which is the standard pitch for M4 machine screws; a 0.5 mm fine pitch exists but is uncommon. The tap drill is 3.3 mm and the normal clearance hole is 4.5 mm.
What screwdriver do I need for Power tool battery pack shell?
The sources do not name the drive. For M4, Phillips heads normally take PH2 and Torx heads T20; socket heads take a 3 mm hex key.
Can I use an imperial screw instead of M4?
No. Imperial look-alike: #8-32 (4.17 mm) — the standard US PC/rack screw, close but not the same. Use a true M4 screw so it does not cross-thread or strip the hole.