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Cone Point Set Screw Dimensions (ISO 4027 / DIN 914, M1.6 to M24)
Guide · Updated October 28, 2026
ISO 4027 covers hexagon socket set screws with cone point (DIN 914), from M1.6 to M24. Values agree across the ISO 4027:2003 preview (iTeh), the Westfield Fasteners sheet, Fuller Fasteners and fasten.it. Check your supplier for critical work.
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Step by step
- Read the thread: Measure the major diameter and pitch. The chart covers coarse M1.6 to M24.
- Pick the key: s is the hex key: M6 takes 3 mm, M8 4 mm, M10 5 mm.
- Spot the shaft: A cone point locates in a 90° spot or drilled dimple. dt max is the truncated tip diameter.
- Check the socket depth: Short screws have the smaller t, so do not over-torque them.
- Tighten: Seat the key fully, then snug. Add threadlocker for vibration.
ISO 4027 cone point set screw dimensions (mm)
Columns: thread, pitch P, hex key s, cone tip diameter dt max, key engagement t min for short and long screws.
- Size | P | s | dt max | t min short | t min long
- M1.6 | 0.35 | 0.7 | 0.4 | 0.7 | 1.5
- M2 | 0.4 | 0.9 | 0.5 | 0.8 | 1.7
- M2.5 | 0.45 | 1.3 | 0.65 | 1.2 | 2
- M3 | 0.5 | 1.5 | 0.75 | 1.2 | 2
- M4 | 0.7 | 2 | 1 | 1.5 | 2.5
- M5 | 0.8 | 2.5 | 1.25 | 2 | 3
- M6 | 1 | 3 | 1.5 | 2 | 3.5
- M8 | 1.25 | 4 | 2 | 3 | 5
- M10 | 1.5 | 5 | 2.5 | 4 | 6
- M12 | 1.75 | 6 | 3 | 4.8 | 8
- M16 | 2 | 8 | 4 | 6.4 | 10
- M20 | 2.5 | 10 | 5 | 8 | 12
- M24 | 3 | 12 | 6 | 10 | 15
Worked example: M6 locating screw
An M6 cone point takes a 3 mm key and has a tip of at most 1.5 mm. Spot-drill the shaft with a 90° point so the cone seats. A long screw gives at least 3.5 mm of key engagement.
Common problems
- Part shifts: the cone is not in its spot, so re-drill the dimple in line.
- Socket rounds out: use a fresh key and seat it fully.
- Screw loosens: add threadlocker.
FAQ
What is ISO 4027?
The hexagon socket set screw with cone point, which seats in a spot-drilled dimple for positive location. DIN 914 is the older equivalent with the same dimensions.
Cone, cup or flat?
Cone (ISO 4027) is for a permanent located position. Cup (ISO 4029) grips a plain shaft. Flat (ISO 4026) suits frequent adjustment.
Is there a newer edition?
Yes. ISO 4027:2026 renames it truncated cone point, adds M30 and defines dt min by formula. This chart shows the 2003 values that the sources agree on.
Why no e or s max/min?
The socket tolerances follow the cup and flat tables. We left them out to keep this chart to the values every source shows.
What was skipped?
e min, s max/min, dt min, the short-length limit and M30.
Related guides and calculators
- Slotted cone point set screws (ISO 7434)
- Slotted set screws (ISO 4766)
- Dog point set screws (ISO 4028)
- Flat point set screws (ISO 4026)
- Cup point set screws (ISO 4029 / DIN 916)
- Socket head cap screws
- Button head socket screws (ISO 7380)
- All free machinist calculators
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