# Do you really need 316L, or is 304 fine for your machined parts?

**URL:** <https://cnc-routers.org/t/do-you-really-need-316l-or-is-304-fine-for-your-machined-parts/94>\
**Category:** Troubleshooting & Support\
**Created:** [October 17, 2026, 2:51pm UTC](https://cnc-routers.org/t/do-you-really-need-316l-or-is-304-fine-for-your-machined-parts/94 "2026-10-17T14:51:57Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![clara\_b](https://cnc-routers.org/user_avatar/cnc-routers.org/clara_b/32/65_2.png) [@clara\_b](https://cnc-routers.org/u/clara_b)\
**Post date:** [October 17, 2026, 2:51pm UTC](https://cnc-routers.org/t/do-you-really-need-316l-or-is-304-fine-for-your-machined-parts/94/1 "2026-10-17T14:51:57Z")

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Working through a batch of parts where the drawing says 316L and I’m not convinced the material call is doing any real work there, so I’m curious how other shops decide.

Both grades come through the shop regularly. The way I’ve been looking at it:

- 304 is fine for most general hardware. Decent corrosion resistance, machines predictably, easy to get.
- 316L earns its cost when the environment gets hostile: repeated washdown, standing moisture, chemical contact, or anything with chlorides in it.

What muddies it for me is food and packaging work. The material call tends to get tangled up with surface finish, how the thing gets cleaned, and whether the part geometry holds a puddle or drains. Specifying 316L on a part with a rough finish and a crevice in it doesn’t really buy you the corrosion resistance you thought you were paying for.

So where’s your line? Cases where 316L is genuinely required, and cases where you’d push back and run 304 instead?

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**Author:** ![dnovak](https://cnc-routers.org/user_avatar/cnc-routers.org/dnovak/32/50_2.png) [@dnovak](https://cnc-routers.org/u/dnovak)\
**Post date:** [October 18, 2026, 1:37pm UTC](https://cnc-routers.org/t/do-you-really-need-316l-or-is-304-fine-for-your-machined-parts/94/2 "2026-10-18T13:37:42Z")

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My line sits closer to what the part touches than what the drawing says. Anything that sees washdown chemicals, brine, or a puddle that never drains, I run 316L and stop arguing. General brackets, guard frames, jigs that live indoors, 304 every time.

The place I got burned was thinking the material alone would save a part. We were cutting some 304 tray dividers on the RCF1325 with a 6mm three flute, and the surface came off looking fine, but the inside corners were tearing just enough to hold water. Six months in, that is where the pitting started, not on the flat faces. Running the same job in 316L with the same tooling would not have fixed it either.

So now I look at corner radius and drain holes before I look at the alloy. If a part cannot shed water, the grade is mostly decoration.

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**Author:** ![jess](https://cnc-routers.org/user_avatar/cnc-routers.org/jess/32/52_2.png) [@jess](https://cnc-routers.org/u/jess)\
**Post date:** [October 18, 2026, 3:18pm UTC](https://cnc-routers.org/t/do-you-really-need-316l-or-is-304-fine-for-your-machined-parts/94/3 "2026-10-18T15:18:51Z")

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@dnovak Sorry if this is obvious, but do you ever override a drawing’s 316L callout for 304 when the part’s environment is benign? If so, how do you justify that to customers?