When Off-the-Shelf Stainless Won't Do
Distributors stock 304 and 316 stainless in common metric and imperial sizes. When you need a bolt that is longer than stocked, has a partial thread, a custom head, a non-standard pitch, or a diameter the catalogue doesn't carry in 316L — machining from bar is the only solution that doesn't involve adapting the design.
For marine hardware, food processing equipment and chemical plant, the material grade matters as much as the dimensions. We machine 316L (low-carbon 316) to the exact specification your application requires, and passivate the finished parts to restore the passive layer after machining.
304 vs 316L — Which Grade for Your Application
| Environment | Recommended grade | Reason |
|---|---|---|
| Indoor / general | 304 | Good corrosion resistance, lower cost |
| Outdoor / coastal | 316L | Salt air resistance, no surface pitting |
| Marine / immersed | 316L | Chloride pitting resistance from molybdenum |
| Food processing | 316L | Resists acidic and chlorinated cleaning agents |
| Chemical plant | 316L | Chloride solution resistance |
| Swimming pools | 316L | Chlorinated water environment |
Have an existing stainless bolt to match? Send the sample — corroded or stripped threads are fine. We measure it, rebuild the drawing for free and machine a replacement in the correct grade. See replacement bolts from a sample or marine replacement parts for related services.
What We Make
| Specification | Options |
|---|---|
| Grade | 304, 316, 316L (low-carbon for welded assemblies) |
| Thread | Metric coarse and fine, UNC, UNF, BSP, custom pitch |
| Head types | Hex, socket cap, button, countersunk, cheese, flanged, eye bolt, stud |
| Length | Any — not limited to catalogue increments; long lengths welcome |
| Finish | As-machined, passivated (ASTM A967), electropolished on request |
| Quantity | Single piece to medium production runs |
Frequently Asked Questions
304 is the standard general-purpose grade. 316 and 316L add molybdenum, which significantly improves resistance to chloride pitting and crevice corrosion. For marine, food processing and chemical environments where salt or cleaning agents are present, 316L is the correct choice.
Yes. We machine 316L to any length, thread pitch, head type and drive that catalogues don't carry — including long lengths, partial threads, custom grip lengths and non-standard diameter combinations.
Yes, on request. Passivation removes free iron introduced during machining and restores the chromium oxide passive layer. For marine and food-contact applications we recommend it as standard.
Yes. Send the bolt in any condition and we measure the thread, head, drive and dimensions, rebuild the drawing for free, confirm with you, then machine in the correct stainless grade. No CAD file needed.
Marine and coastal environments, food processing equipment cleaned with chlorinated chemicals, chemical plant handling chloride solutions, outdoor coastal architecture, and swimming pools. Wherever prolonged chloride exposure would eventually pit 304.
Yes. Single replacement bolts and small sets are normal orders. There is no tooling cost on machined stainless fasteners.
Get Stainless Bolts Quoted
Drawing or sample both accepted. Engineers reply in 24h.