A2 Stainless Steel (ISO 3506 group A2 (304 / 1.4301), commonly supplied A2-70) is the most common stainless group for indoor and general outdoor fasteners. When one-piece clamp shaft collars are specified in this grade, the dimensions remain per Trade series (one-piece clamp-type shaft collars); the material determines corrosion behavior (good general corrosion resistance) and the service temperature range (approx. -200 °C to +400 °C, subject to the property class and the joint). Both are covered below with the size table.
Why Choose A2 Stainless Steel for One-Piece Clamp Shaft Collars
The most common stainless group for indoor and general outdoor fasteners. For one-piece clamp shaft collars, this matters when good general corrosion resistance is the primary requirement.
Mechanical & Physical Properties
| Grade designation | ISO 3506 group A2 (304 / 1.4301), commonly supplied A2-70 |
|---|---|
| Magnetic response | Largely non-magnetic |
| Service temperature | approx. -200 °C to +400 °C, subject to the property class and the joint |
| Corrosion characteristic | Good general corrosion resistance |
Galvanic & Galling Considerations
For stainless one-piece clamp shaft collars the compatibility question is galvanic rather than galling: joined to aluminum or galvanized steel in wet service, stainless drives corrosion of the less-noble metal. Isolate with a coating, sleeve or non-conductive washer where the joint sees moisture. Note also that stainless is softer than hardened carbon steel, so where the part carries a wear or shear duty, check the load against the grade before substituting.
Comparable Grades
For One-Piece Clamp Shaft Collars, the alternative stainless grade is A4 (316). Choose A2 (304) for general use and A4 (316) wherever chlorides are present; the molybdenum in A4 is the whole difference. Remember that stainless is the corrosion answer, not the strength answer — for load, look at class 8.8 or 10.9 instead.
Using Stainless Fasteners in Aluminum
Stainless steel is more noble than aluminum, so with an electrolyte present — rain, condensation, salt spray — the aluminum becomes the anode and corrodes at the joint. Area ratio decides how bad it gets: a small stainless fastener in a large aluminum section is normally acceptable, a large stainless fastener in thin aluminum is not. Where the joint gets wet, isolate the metals with a coated or nylon washer and a sealant, or specify an aluminum or coated fastener instead.
Sizes of One-Piece Clamp Shaft Collars Available in A2 Stainless Steel
| Bore (mm) | Outside diameter (mm) | Width (mm) | Clamp screw |
|---|---|---|---|
| 6 | 18 | 9 | M3 socket head cap screw |
| 8 | 20 | 9 | M3 socket head cap screw |
| 10 | 24 | 11 | M4 socket head cap screw |
| 12 | 26 | 11 | M4 socket head cap screw |
| 15 | 32 | 14 | M5 socket head cap screw |
| 16 | 34 | 14 | M5 socket head cap screw |
| 20 | 40 | 15 | M5 socket head cap screw |
| 25 | 45 | 15 | M6 socket head cap screw |
| 30 | 54 | 18 | M6 socket head cap screw |
| 35 | 60 | 18 | M8 socket head cap screw |
| 40 | 66 | 20 | M8 socket head cap screw |
