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Slotted Cheese Head Screw Dimensions (ISO 1207 / DIN 84, M1.6 to M10)
Guide · Updated October 28, 2026
ISO 1207 covers slotted cheese head screws, M1.6 to M10, product grade A; it replaced DIN 84. Values agree across the ISO 1207:2011 published table, fasteners.eu and Westfield Fasteners. Nominal values; check the standard for tolerances.
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Step by step
- Find the thread: Pick the row for your thread size, M1.6 to M10.
- Size the counterbore: Use dk and k. A cheese head is a tall flat-topped cylinder, so it sinks fully into a counterbore.
- Pick the screwdriver: Match the blade to slot width n; the blade should fill the slot.
- Check thread length: b is the minimum thread on longer screws; short screws are threaded to the head.
ISO 1207 slotted cheese head screw dimensions (mm)
Columns: thread d, pitch P, head diameter dk max, head height k max, slot width n nominal, slot depth t min, wall under slot w min, thread length b min.
- Size | P | dk | k | n | t | w | b
- M1.6 | 0.35 | 3 | 1.1 | 0.4 | 0.45 | 0.4 | 25
- M2 | 0.4 | 3.8 | 1.4 | 0.5 | 0.6 | 0.5 | 25
- M2.5 | 0.45 | 4.5 | 1.8 | 0.6 | 0.7 | 0.7 | 25
- M3 | 0.5 | 5.5 | 2 | 0.8 | 0.85 | 0.75 | 25
- (M3.5) | 0.6 | 6 | 2.4 | 1 | 1 | 1 | 38
- M4 | 0.7 | 7 | 2.6 | 1.2 | 1.1 | 1.1 | 38
- M5 | 0.8 | 8.5 | 3.3 | 1.2 | 1.3 | 1.3 | 38
- M6 | 1 | 10 | 3.9 | 1.6 | 1.6 | 1.6 | 38
- M8 | 1.25 | 13 | 5 | 2 | 2 | 2 | 38
- M10 | 1.5 | 16 | 6 | 2.5 | 2.4 | 2.4 | 38
Worked example: M4 cover screw
An M4 ISO 1207 head is 7 mm across and 2.6 mm high. An 8 mm by 3 mm counterbore sets it just below the surface. The slot is 1.2 mm wide and at least 1.1 mm deep, so use a 1.2 mm blade.
Common problems
- Slot cams out or chews up: the blade is too narrow or worn; match it to slot width n.
- Small screws sit high in a counterbore: old DIN 84 vs ISO 1207 head heights differ at M1.6 to M2.5; check which you have.
- Head snaps off in brass or A2: slotted screws take little torque; snug them, do not lean on them.
FAQ
Is DIN 84 the same as ISO 1207?
Almost. ISO 1207 replaced DIN 84. Head heights differ only at M1.6, M2 and M2.5: DIN 84 gives k 1.0, 1.3 and 1.6 mm, ISO gives 1.1, 1.4 and 1.8 mm.
What is w?
The minimum wall thickness from the bottom of the slot to the bearing face.
Why is t a minimum?
The standard sets only a minimum slot depth so the screwdriver has enough grip.
Is M3.5 common?
It is a non-preferred size (in brackets); use M3 or M4 where you can.
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