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Cup Point Set Screw Dimensions (ISO 4029 / DIN 916, M1.6 to M24)
Guide · Updated October 28, 2026
ISO 4029 covers hexagon socket set screws with cup point (DIN 916), from M1.6 to M24. Values agree across the ISO 4029:2003 preview (iTeh), globalfastener, Fuller Fasteners and Brighton-Best, and fasten.it and fasteners.eu match the cup diameters. 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.
- Check the cup: dz is the cup rim diameter that bites into the shaft. Leave a flat or spot wider than dz max.
- 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 4029 cup point set screw dimensions (mm)
Columns: thread, pitch P, hex key s, cup diameter dz max and min, key engagement t min for short and long screws.
- Size | P | s | dz max | dz min | t min short | t min long
- M1.6 | 0.35 | 0.7 | 0.80 | 0.55 | 0.7 | 1.5
- M2 | 0.4 | 0.9 | 1.00 | 0.75 | 0.8 | 1.7
- M2.5 | 0.45 | 1.3 | 1.20 | 0.95 | 1.2 | 2
- M3 | 0.5 | 1.5 | 1.40 | 1.15 | 1.2 | 2
- M4 | 0.7 | 2 | 2.00 | 1.75 | 1.5 | 2.5
- M5 | 0.8 | 2.5 | 2.50 | 2.25 | 2 | 3
- M6 | 1 | 3 | 3.00 | 2.75 | 2 | 3.5
- M8 | 1.25 | 4 | 5.0 | 4.7 | 3 | 5
- M10 | 1.5 | 5 | 6.0 | 5.7 | 4 | 6
- M12 | 1.75 | 6 | 8.00 | 7.64 | 4.8 | 8
- M16 | 2 | 8 | 10.00 | 9.64 | 6.4 | 10
- M20 | 2.5 | 10 | 14.00 | 13.57 | 8 | 12
- M24 | 3 | 12 | 16.00 | 15.57 | 10 | 15
Worked example: M8 pulley set screw
An M8 cup point takes a 4 mm key. Its cup is 4.7 to 5.0 mm across, so spot-drill the shaft about 5.5 mm. A short screw gives at least 3 mm of key engagement.
Common problems
- Hub will not come off: the cup has raised a burr, so file it before pulling.
- Socket rounds out: use a fresh key and seat it fully.
- Screw loosens: add threadlocker or a second screw on top.
FAQ
What is ISO 4029?
The hexagon socket set screw with cup point. Its sharp rim bites into the shaft for a strong hold. DIN 916 is the older German equivalent.
Cup or flat point?
Cup point (ISO 4029) holds best but marks the shaft. Flat point (ISO 4026) suits frequent adjustment.
Is DIN 916 the same?
Nearly. At M12 the DIN short-screw t is 4.5, while ISO gives 4.8. This chart uses the ISO values. DIN also adds M14, M18 and M22.
Why no e or short-length columns?
e min differs between the 1993 and 2003 tables, and sources disagree on the short-length limit, so both are left out.
What was skipped?
e min, s max/min, the short-length limit and the DIN-only sizes M1.4, M1.8, M14, M18 and M22.
Related guides and calculators
- Slotted cup point set screws (ISO 7436)
- Slotted cone point set screws (ISO 7434)
- Slotted set screws (ISO 4766)
- Dog point set screws (ISO 4028)
- Cone point set screws (ISO 4027)
- Flat point set screws (ISO 4026)
- Socket head cap screws
- Button head socket screws (ISO 7380)
- Countersunk socket screws (ISO 10642)
- All free machinist calculators
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