01
The blank bows after milling
A 1.5 mm 304 panel is cut on one face only. The rolled-in stress releases and the plate bows 0.3–0.8 mm across 400 mm. Assembly gaps open up, and the fixture you built around the old part no longer fits.
Stainless 304 sheet parts
CNC Machining 304 Stainless Steel Sheet Parts
We mill and turn 304 and 304L sheet into brackets, panels, enclosures and mounting plates. Flat blanks stay flat, holes stay on position, edges stay clean enough for the next process.
304 / 304L sheet±0.005 mm0.5–20 mm stockFrom one pieceNDA on request
15 yearsMetal part production since 2011
127High-precision CNC machines
±0.005 mmAchievable tolerance on 304
12 hoursQuote plus free DFM analysis
Where 304 sheet goes wrong
Four problems engineers bring to us after a bad run
All four come from the same root cause: 304 work-hardens fast and moves when you cut it.
02
Holes drift and ream oversize
Spot drilling without a rigid setup lets the drill walk in 304. A 6 mm hole comes out 6.15 mm and oval. Bolts rattle, dowel pins lose their press fit, and the whole batch gets scrapped or welded up.
03
Burrs survive the tumbler
Sheared 304 edges leave a rolled burr that hand deburring misses. The part passes visual check but cuts the operator, or sheds a chip into a sealed enclosure. Rework eats a week you did not plan for.
04
Galling ruins the threads and the tool
Cutting 304 dry or at the wrong feed welds chips to the tap. Threads tear, the tap snaps in the hole, and the part is now a paperweight. Tools that cut 6061 all day fail on this grade within minutes.
How we hold 304 sheet
Machine it like a hard material, not like aluminum
Rigid setups, sharp tooling, real coolant. That is the whole trick.
Setup and sequence
Balance the cut so the plate stays flat
We remove stock from both faces instead of one. Equal depths on a 304 blank keep the stress balanced, so the part stays within 0.05 mm of flat after you unclamp it. For thin panels under 3 mm we rough, let the part sit, then finish.
Fixtures are cut for the job. Vacuum plates on thin sheet, soft jaws on brackets, and supports under unsupported spans. Clamping pressure gets checked before the first cut, not after the tenth.
- 1Rough and finish in separate operationsReduces heat soak and dimensional drift on thin sheet.
- 2Sharp carbide, high feed per toothCuts under the work-hardened skin instead of rubbing it.
- 3Coolant through the cutKeeps chip welding off the edge and out of the thread.
Tolerance and inspection
Measure the feature that matters, then the rest
A 304 bracket can hold ±0.005 mm on a bored hole and still be useless if the hole sits 0.2 mm off the datum. We control position first, then size. Datums come off your drawing, not off our convenience.
Every run gets a first-article check and a final inspection before it ships. CMM reports, material certificates and surface finish readings are available when your quality file needs them.
- 1Position before sizeHole location is what makes parts assemble or not.
- 2100% inspection before shipmentRaw material check, in-process monitoring, final sign-off.
- 3Reports on requestCMM data, material certs and finish values travel with the parts.
Grade and process choice
When 304 is the right call on a sheet part
If your part sees food, weather or washdown, read the 304 rows.
| Grade | Pick it when | Watch out for |
|---|---|---|
| 304 / 304L | General corrosion resistance, food and washdown areas | Work-hardens fast; needs balanced cuts |
| 316 / 316L | Chlorides, salt spray, marine and medical exposure | Higher cost, slightly tougher to cut |
| 303 | You need fast turning and easy chip control | Lower corrosion resistance than 304 |
| 430 | Indoor panels where cost drives the build | Magnetic; limited corrosion resistance |
| 17-4PH | High strength plus corrosion resistance in one part | Needs heat treatment to reach full strength |
What we do on 304
Sheet, milled and turned parts under one roof
One supplier for the blank, the machining and the finish.
01
3, 4 and 5-axis milling
Flat panels, pockets, slots and contoured edges on 304 sheet. 16 simultaneous 5-axis centers handle angled faces in one setup.
02
CNC turning
Bushings, spacers, threaded inserts and fittings in 304 bar or plate stock. Live tooling cuts cross holes without a second op.
03
Sheet metal fabrication
Laser cutting, forming and bending for enclosures and chassis that pair with machined 304 details.
04
Surface finishing
Bead blasting, brushing, polishing, passivation and laser marking. Marked characters down to 1.5 mm tall.
05
Rapid prototyping
One-off 304 brackets and test panels before you commit to a production run.
06
Assembly and packing
Hardware install, sub-assembly, protective packing and export shipping documentation.
Process envelope
What our machines can reach on 304 sheet
Numbers below are the working range, not a wish list.
| Item | Range |
|---|---|
| Sheet thickness | 0.5 mm to 20 mm |
| Maximum part size | 4,000 mm envelope, 4,000 × 400 × 150 mm travel |
| General machining tolerance | ±0.005 mm (±0.0002 in) |
| Surface finish | Ra 0.8–1.6 μm standard, Ra 0.2–0.8 μm on request |
| Threads and taps | M1.6 and up, rolled or cut |
| Laser marking | Minimum character height 1.5 mm |
| Order quantity | One prototype to 10,000+ part runs |
| Lead time | Quote in 12 hours, production start in 24 hours, parts ship in 3–5 days |
Why engineers keep sending 304 work here
Capacity, controls and people that match the part
Six reasons that show up on the shop floor, not in a brochure.
15Y
Making metal parts since 2011
Three wholly-owned plants and 7,600 m² of manufacturing space in Dongguan, plus a factory in Singapore.
127
High-precision CNC machines
16 simultaneous 5-axis centers, 12 four-axis mills, 27 three-axis machines and 16 mill-turn centers. The right machine gets picked per feature.
±0.005 mm
Tolerance we can hold and prove
CMM inspection and 100% check before shipment. Reports go out with the parts when your quality file asks for them.
12H
Quote and DFM in half a day
Send a STEP file and a drawing. We come back with pricing and a manufacturability review within 12 hours, production can start inside 24 hours.
4
Certified quality systems
ISO 9001:2015, IATF 16949:2016, ISO 13485:2016 and ISO 27001:2022 cover the plants and the data handling.
150
Technicians on the floor
Programmers, machinists and inspectors work the same job. When a 304 part fights back, the person who cut it talks to the person who designed it.
±0.005 mmAchievable machining tolerance
99.99%Qualification rate
3–5 daysTypical shipping window
4,000 mmMaximum processing size
Where these parts end up
Industry requirements and what we deliver
Electronics enclosures
Housing panels and chassis plates where EMI gasket grooves must line up with the lid.
- ±0.005 mm
- Ra 0.8–1.6 μm
- 100% inspection
Industrial machinery
Mounting brackets and guard plates that take vibration without cracking at the bend line.
- 0.5–20 mm
- 4,000 mm envelope
- Bead blasting
Food and washdown equipment
Panels that see daily cleaning and cannot rust at a scratch or a cut edge.
- 304 / 304L
- Passivation
- Material certs
Automotive and EV fixtures
Test fixtures and battery pack plates that hold position across a production run.
- IATF 16949
- ±0.0002 in
- 12-hour DFM
FAQs
Questions we get about 304 sheet machining
Can you machine 304 sheet without the part warping?
Yes, if the cut is balanced. We remove stock from both faces and split roughing from finishing on thin panels. That keeps the stress in the sheet from pulling the part out of flat after unclamping.
Parts under 3 mm thick are the ones that move most. Tell us the flatness callout and we will plan the sequence around it.
What is the thinnest 304 sheet you can hold tolerance on?
We work down to 0.5 mm stock. Below roughly 1.5 mm, ±0.005 mm on every feature stops being realistic because the sheet deflects under cutting force.
On those parts we agree on which dimensions carry the tolerance and which ones can sit looser. The critical hole gets the tight number, the outline does not need it.
Should I choose 304 or 316 for my application?
Pick 304 for general corrosion resistance, indoor and outdoor parts, and food-contact surfaces that are not heavily chlorinated. It machines better and costs less than 316.
Move to 316 or 316L when the part sees salt spray, chloride cleaning agents or marine air. The molybdenum content is what buys you that resistance.
How do you stop galling and torn threads on 304?
Sharp tooling, proper feed per tooth, and coolant that reaches the cutting edge. Rubbing a dull tool against 304 hardens the surface and welds chips to the tap.
We also roll threads where the geometry allows. Forming the thread instead of cutting it avoids the chip problem and leaves a stronger thread.
Do you offer any order quantity limit?
There is no minimum order quantity. A single prototype 304 bracket can go through the same machines as a 10,000-piece run.
Unit cost drops as volume rises, so it pays to send the full annual forecast even if you start with one part.
What do you need to quote a 304 sheet part?
A 3D model in STEP or IGES, plus a 2D drawing with tolerances, datums and finish callouts. If you only have a sample, we can scan it and work from the measured geometry.
Send both files and you get pricing plus a DFM review within 12 hours. An NDA is available before you upload anything.
Which surface finishes work on 304?
Bead blasting, tumbling, brushing and polishing all work. Passivation is common after machining because it restores the oxide layer on cut edges.
Laser marking holds well on 304. Minimum character height is 1.5 mm, so plan your serial numbers and logos around that limit.
How do I track my order without visiting the factory?
You get a named contact who reports progress at set points: material in, machining started, inspection done, packed for shipping.
Inspection reports and photos of the finished parts go out before the boxes leave, so you can catch a problem while it is still fixable.
Send your 304 sheet part for a quote
Upload a STEP file and drawing. You get pricing and a manufacturability review within 12 hours, and every part is inspected before it ships.
12-hour quote100% inspectionFrom one piece
