Gib-Head Taper Keys (DIN 6887) manufactured in A4 Stainless Steel (ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80) are dimensioned to DIN 6887 (gib-head taper keys) — 1:100 taper. 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 A4 Stainless Steel for Gib-Head Taper Keys (DIN 6887)
Specified for marine, coastal and chemical applications. For gib-head taper keys (din 6887), this matters when superior, including marine and chloride environments is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80 |
|---|---|
| Magnetic response | Largely non-magnetic |
| Service temperature | approx. -200 °C to +400 °C, subject to the property class and the joint |
| Corrosion characteristic | Superior, including marine and chloride environments |
Corrosion Behavior in Service
A4 (316) adds 2–3% molybdenum to the A2 (304) composition, which dramatically improves resistance to chloride-pitting corrosion. For Gib-Head Taper Keys (DIN 6887) in marine, coastal, swimming-pool or food-processing environments, A4 is the default selection.
Comparable Grades
For Gib-Head Taper Keys (DIN 6887), the alternative stainless grade is A2 (304). The practical dividing line is chlorides: A2 (304) is fine until salt is involved, and A4 (316) exists for the cases where it is — coastal, marine and road-salt service. Neither reaches the strength of a plated class 8.8 or 10.9 fastener.
Using Stainless Fasteners in Aluminum
Expect the aluminum to corrode, not the fastener — stainless sits higher in the galvanic series, so the aluminum is the one that gives up material. A small fastener in a thick section spreads the loss over a large area and is usually fine; a large fastener in thin sheet concentrates it and is not. Keep water out of the joint, or isolate the two metals with a nylon or coated washer and a sealant.
Sizes of Gib-Head Taper Keys (DIN 6887) Available in A4 Stainless Steel
| Shaft diameter over | to and including | Key width b (mm) | Key height h (mm) | Head |
|---|---|---|---|---|
| 10 | 12 | 4 | 4 | gib head |
| 12 | 17 | 5 | 5 | gib head |
| 17 | 22 | 6 | 6 | gib head |
| 22 | 30 | 8 | 7 | gib head |
| 30 | 38 | 10 | 8 | gib head |
| 38 | 44 | 12 | 8 | gib head |
| 44 | 50 | 14 | 9 | gib head |
| 50 | 58 | 16 | 10 | gib head |
| 58 | 65 | 18 | 11 | gib head |
| 65 | 75 | 20 | 12 | gib head |
