Socket Set Screws, UNC (Flat, Cone, Dog and Cup Point) manufactured in Property Class 12.9 Steel (ISO 898-1 property class 12.9) are dimensioned to ASME B18.3. The sections below give the mechanical and physical properties of the grade, its behavior in corrosive and elevated-temperature service, and the full size table.
Why Choose Property Class 12.9 Steel for Socket Set Screws, UNC (Flat, Cone, Dog and Cup Point)
The highest common strength class, for high-load machine assembly. For socket set screws, unc (flat, cone, dog and cup point), this matters when requires plating or black-oxide protection is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ISO 898-1 property class 12.9 |
|---|---|
| Magnetic response | Magnetic |
| Service temperature | commonly limited to approx. +300 °C; confirm against the coating and the load |
| Corrosion characteristic | Requires plating or black-oxide protection |
Corrosion Behavior in Service
Carbon and alloy steel socket set screws, unc (flat, cone, dog and cup point) require a coating for corrosion protection. Zinc plating (with or without passivation) is the most common; hot-dip galvanizing is used for outdoor structural service; black-oxide is mainly a tarnish-prevention finish for tool-room use.
Comparable Grades
For Socket Set Screws, UNC (Flat, Cone, Dog and Cup Point), class 8.8 is the comparable strength step. Move up when the joint preload approaches the proof load of the current class; move down when the joint is over-specified. For corrosion-critical service, switch to stainless A2 or A4.
Sizes of Socket Set Screws, UNC (Flat, Cone, Dog and Cup Point) Available in Property Class 12.9 Steel
| Size | Type | Pitch P (mm) | t (mm) | dp (mm) | dt (mm) | df (mm) | Hex socket s (mm) | z (mm) | Length range l (in) | Reference standard |
|---|---|---|---|---|---|---|---|---|---|---|
| #0 | Hexagon socket set screws with flat point | 0.318 | 1.27 | 0.762 | 0.305 | 0.978 | 0.711 | 0.381 | 1/16"~1 1/2" | ASME B18.3 |
| #0 | Hexagon socket set screws with cone point | 0.318 | 1.27 | 0.762 | 0.305 | 0.978 | 0.711 | 0.381 | 1/16"~1 1/2" | ASME B18.3 |
| #0 | Hexagon socket set screws with dog point | 0.318 | 1.27 | 0.762 | 0.305 | 0.978 | 0.711 | 0.381 | 1/16"~1 1/2" | ASME B18.3 |
| #0 | Hexagon socket set screws with cup point | 0.318 | 1.27 | 0.762 | 0.305 | 0.978 | 0.711 | 0.381 | 1/16"~1 1/2" | ASME B18.3 |
| #1 | Hexagon socket set screws with flat point | 0.397 | 1.524 | 0.927 | 0.371 | 1.194 | 0.889 | 0.483 | 1/16"~1 1/2" | ASME B18.3 |
| #1 | Hexagon socket set screws with cone point | 0.397 | 1.524 | 0.927 | 0.371 | 1.194 | 0.889 | 0.483 | 1/16"~1 1/2" | ASME B18.3 |
| #1 | Hexagon socket set screws with dog point | 0.397 | 1.524 | 0.927 | 0.371 | 1.194 | 0.889 | 0.483 | 1/16"~1 1/2" | ASME B18.3 |
| #1 | Hexagon socket set screws with cup point | 0.397 | 1.524 | 0.927 | 0.371 | 1.194 | 0.889 | 0.483 | 1/16"~1 1/2" | ASME B18.3 |
| #2 | Hexagon socket set screws with flat point | 0.454 | 1.524 | 1.092 | 0.437 | 1.397 | 0.889 | 0.559 | 1/16"~2 1/2" | ASME B18.3 |
| #2 | Hexagon socket set screws with cone point | 0.454 | 1.524 | 1.092 | 0.437 | 1.397 | 0.889 | 0.559 | 1/16"~2 1/2" | ASME B18.3 |
| #2 | Hexagon socket set screws with dog point | 0.454 | 1.524 | 1.092 | 0.437 | 1.397 | 0.889 | 0.559 | 1/16"~2 1/2" | ASME B18.3 |
| #2 | Hexagon socket set screws with cup point | 0.454 | 1.524 | 1.092 | 0.437 | 1.397 | 0.889 | 0.559 | 1/16"~2 1/2" | ASME B18.3 |
| #3 | Hexagon socket set screws with flat point | 0.529 | 1.778 | 1.257 | 0.503 | 1.626 | 1.27 | 0.635 | 1/8"~2 1/2" | ASME B18.3 |
| #3 | Hexagon socket set screws with cone point | 0.529 | 1.778 | 1.257 | 0.503 | 1.626 | 1.27 | 0.635 | 1/8"~2 1/2" | ASME B18.3 |
| #3 | Hexagon socket set screws with dog point | 0.529 | 1.778 | 1.257 | 0.503 | 1.626 | 1.27 | 0.635 | 1/8"~2 1/2" | ASME B18.3 |
| #3 | Hexagon socket set screws with cup point | 0.529 | 1.778 | 1.257 | 0.503 | 1.626 | 1.27 | 0.635 | 1/8"~2 1/2" | ASME B18.3 |
| #4 | Hexagon socket set screws with flat point | 0.635 | 1.778 | 1.422 | 0.569 | 1.841 | 1.27 | 0.711 | 1/8"~4" | ASME B18.3 |
| #4 | Hexagon socket set screws with cone point | 0.635 | 1.778 | 1.422 | 0.569 | 1.841 | 1.27 | 0.711 | 1/8"~4" | ASME B18.3 |
| #4 | Hexagon socket set screws with dog point | 0.635 | 1.778 | 1.422 | 0.569 | 1.841 | 1.27 | 0.711 | 1/8"~4" | ASME B18.3 |
| #4 | Hexagon socket set screws with cup point | 0.635 | 1.778 | 1.422 | 0.569 | 1.841 | 1.27 | 0.711 | 1/8"~4" | ASME B18.3 |
| #5 | Hexagon socket set screws with flat point | 0.635 | 2.032 | 1.575 | 0.635 | 2.045 | 1.575 | 0.762 | 3/16"~4" | ASME B18.3 |
| #5 | Hexagon socket set screws with cone point | 0.635 | 2.032 | 1.575 | 0.635 | 2.045 | 1.575 | 0.762 | 3/16"~4" | ASME B18.3 |
| #5 | Hexagon socket set screws with dog point | 0.635 | 2.032 | 1.575 | 0.635 | 2.045 | 1.575 | 0.762 | 3/16"~4" | ASME B18.3 |
| #5 | Hexagon socket set screws with cup point | 0.635 | 2.032 | 1.575 | 0.635 | 2.045 | 1.575 | 0.762 | 3/16"~4" | ASME B18.3 |
| #6 | Hexagon socket set screws with flat point | 0.794 | 2.032 | 1.753 | 0.701 | 2.273 | 1.575 | 0.889 | 1/8"~4" | ASME B18.3 |
| #6 | Hexagon socket set screws with cone point | 0.794 | 2.032 | 1.753 | 0.701 | 2.273 | 1.575 | 0.889 | 1/8"~4" | ASME B18.3 |
| #6 | Hexagon socket set screws with dog point | 0.794 | 2.032 | 1.753 | 0.701 | 2.273 | 1.575 | 0.889 | 1/8"~4" | ASME B18.3 |
| #6 | Hexagon socket set screws with cup point | 0.794 | 2.032 | 1.753 | 0.701 | 2.273 | 1.575 | 0.889 | 1/8"~4" | ASME B18.3 |
| #8 | Hexagon socket set screws with flat point | 0.794 | 2.286 | 2.07 | 0.833 | 2.692 | 1.981 | 1.016 | 1/8"~5" | ASME B18.3 |
| #8 | Hexagon socket set screws with cone point | 0.794 | 2.286 | 2.07 | 0.833 | 2.692 | 1.981 | 1.016 | 1/8"~5" | ASME B18.3 |
Dimensions are independent of the material: every size above is available in Property Class 12.9 Steel.
Custom manufacturing · Made to drawing
Need this screw in a grade that is not listed?
Grade 12 9 Steel is one of the grades the catalog describes. Lengths and thread lengths outside the standard table are the commonest request, followed by a drive the standard does not offer and a head marked with your own part number. Made by cold heading or warm forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.

