Stainless steel housings
Enclosures with pockets, cover faces and mounting holes. Mark sealing lands, mating faces and areas with specific cleaning or finish requirements.
Stainless steel housings, bushings and machined components
Mounting brackets
Brackets and supports with holes on more than one face. Include the assembly datums and the surfaces that must remain free from fixture marks.
Fixture plates
Locating plates with hole patterns, slots and reference faces. Identify the features used to position the assembly and the inspection condition for flatness.
Bushings and sleeves
Cylindrical parts with fitted bores, shoulders and bearing surfaces. State the mating part, finished fit and any material or heat-treatment requirement.
Flanges and hubs
Turned diameters combined with bolt circles and mounting faces. Call out the relationship between the bore, face and hole pattern rather than only the outside size.
Ported blocks
Blocks with cross-holes, threads and internal passages. Show port connections, thread engagement and the locations where burr removal and cleanliness need verification.
Choosing between 303, 304, 316 and 17-4 PH
303 for parts that need extensive machining
Sulfur is added to 303 to improve machinability. The trade-off is lower corrosion resistance than non-free-machining austenitic grades; confirm that the service conditions allow it.[1][5]
- Specify with the grade
- Free-machining austenitic stainless
- Before quotation
- Name the required standard and stock form. Do not substitute 303 for a drawing-specified 304 or 316 grade without approval.
304 and 304L for general-purpose components
304 is a general-purpose austenitic stainless steel. 304L has lower carbon, which helps limit intergranular corrosion after welding. The specified grade still needs to match the part and fabrication plan.[2]
- Specify with the grade
- Grade and supplied condition
- Before quotation
- Confirm whether the drawing requires 304, 304L or certified dual-grade material, and identify any welding after machining.
316 and 316L for more demanding environments
The molybdenum in 316-family grades supports higher corrosion resistance. 316L is the low-carbon option. Use the fluid, temperature and cleaning conditions to review suitability, not the grade name alone.[3]
- Specify with the grade
- Service exposure and material standard
- Before quotation
- Tell us what touches the part, including cleaning chemicals. A 316 callout is not a blanket guarantee against corrosion.
17-4 PH when strength and hardness are specified
17-4 PH is a precipitation-hardening stainless steel. Its heat-treatment condition belongs in the specification alongside the grade; the machining and inspection sequence should reflect the required final condition.[4]
- Specify with the grade
- Drawing-specified heat-treatment condition
- Before quotation
- State the required condition, hardness or mechanical properties and the records needed. We will review the sequence before quoting.
Use the material callout on your drawing. Other stainless grades can be reviewed; the options here do not confirm stock availability or authorize a substitution.
Milling and turning stainless steel to your drawing
CNC milling for housings and hole patterns
For pockets, slots and faces, show which features share a datum and where a cutter can enter. We review the grade, fixture support and sequence together with the drawing.
View the Machining ServiceCNC turning for bores, shafts and sleeves
For round parts, define the fitted diameters, shoulders and thread details. Include flats and cross-holes in the same request so secondary operations are part of the quotation.
View the Machining ServiceFive-axis machining for angled features
Multi-face parts may need additional tool access. We compare indexed and simultaneous approaches with the geometry; extra axes do not automatically make a part more economical.
View the Machining ServiceAustenitic stainless can work-harden during machining and generate difficult chips, heat and tool wear. The cutting plan must suit the actual grade and condition, rather than reuse an aluminum setup.[5]
Design details that affect stainless steel machining
Deep bores and intersecting holes
Show the depth, access and connection between internal passages. Identify burr-sensitive intersections and how they can be checked; the outside shape alone does not describe the finished requirement.
Thin walls and long unsupported features
Mark the surfaces that must remain straight or flat after the part is released from its fixture. Review support and the order of operations before reducing wall thickness or adding a tight geometric tolerance.
Threads, shoulders and mating surfaces
Give the thread standard, class and useful engagement length. Tell us about repeated assembly, mating materials and contact conditions so any wear or seizure concern can be raised during review.
Material removal after machining
Call out areas affected by polishing or other later operations. Separate a visual finish from a dimensional requirement and state whether the drawing limits apply before or after the final process.
Which features should we review with your drawing?
No review topics selected.
Passivation, electropolishing and stainless surface finishes
As-machined and deburred
Use the drawing to define edge breaks, local roughness and permitted tool marks. A machined surface is not a substitute for a specified cleaning or corrosion-treatment process.
Identify sealing lands, fitted bores and protected contact faces.
Passivation after machining
Passivation removes surface contamination such as free iron and supports the alloy’s inherent corrosion resistance. It is not a paint-like coating and does not replace prior cleaning.[6]
Specify the process requirement, acceptance test and records for the grade.
Electropolishing for a smoother surface
Electropolishing removes a controlled amount of surface metal. Include the surfaces to treat and the final dimensions when it is part of the finishing plan.[7]
Agree material removal, critical edges, contact locations and inspection.
Brushed or mechanically polished finishes
Use an agreed surface reference and drawing callouts to define the result. Mark visible faces, the direction of the finish and the areas that should not be blended or rounded.
Confirm cosmetic acceptance separately from size and geometry.
Finishing routes are reviewed for the actual grade and geometry. Record any required sequence of cleaning, treatment and inspection in the order; selecting a finish here does not approve it.
Define stainless part tolerances in the finished condition
| Feature | What to put on the drawing | What to agree for inspection |
|---|---|---|
| Fitted bores and shafts | State the mating part, limit dimensions and datum features. Define the final supplied condition. | Agree the measurement method and when the size is checked relative to heat treatment and finishing. |
| Threads and sealing faces | Specify the thread class, usable depth, sealing geometry and any surface-finish callout. | Name the agreed gauge or check and the surfaces included in dimensional or roughness inspection. |
| Flatness, position and runout | Show the datum system and the condition in which the part is used or measured. | Agree fixturing, support and the features included in the report, not just a list of overall dimensions. |
| Polished or treated surfaces | Identify surfaces to process and the dimensions or edges that must remain within limits. | Check the finished result against the drawing; visual appearance and dimensional acceptance are separate. |
A single tolerance figure cannot describe every stainless grade, part size and feature. Send the critical dimensions and intended inspection conditions so we can confirm feasibility for your drawing.
Prepare your stainless steel machining requirements
Name the grade and supplied condition
“Stainless steel” is not a complete material callout. Include the grade, stock form and governing specification. For a heat-treated part, identify the required final condition and the records used to confirm it.
Describe exposure and cleaning
List the liquid or atmosphere in contact with the part, service temperature and cleaning method. Tell us about welded joints and contact with other materials. Material suitability needs application review, not a selection based only on the highest grade number.
Keep the files at the same revision
Send a matching CAD model and 2D drawing with units. Keep proposed substitutes and open questions separate from the approved requirements, and resolve them before production release.
Your stainless steel parts brief
These entries describe a request for review. They do not confirm material suitability, stock, process approval or an order.
Material traceability and inspection for stainless parts
Link material records to the supplied stock
Agree which material certificate is needed and how the heat or batch identity relates to the order. Material paperwork does not replace inspection of the machined features.
Record the final condition when it matters
Where a specified heat-treatment condition or hardness is part of acceptance, define the evidence required and the stage at which it is checked. Keep those records tied to the drawing revision and order.
Verify treatment and cleanliness requirements
State the agreed surface treatment, acceptance method and reporting scope. A visually bright surface alone does not prove that free-iron contamination has been removed.[6]
Agree what the dimensional report covers
List the critical characteristics, inspection method and sample size. Keep dimensional results, finish checks and any separate application testing identifiable rather than grouping everything as a generic quality certificate.
From stainless prototypes to repeat production
Use the intended grade for a functional sample
Identify what the sample is meant to verify: assembly, surface contact, appearance or a specific test. Record any temporary difference from the production specification so sample approval is not misinterpreted.
Approve the drawing, condition and finish together
Keep the approved revision, material requirement, treatment route and inspection scope in one release record. Resolve proposed changes before the pilot or production batch is started.
Keep repeat orders tied to the approved revision
Quote the new quantity and note any drawing changes, packaging needs or revised arrival date. Define how material identity and inspection records should accompany the next delivery.
What affects the cost of stainless steel CNC machining?
Grade, stock condition and cutting time
Compare quotations against the same grade and supplied condition. Stock size, material removal, tool access and the amount of setup work all belong in the cost discussion; finished-part weight alone is not enough.
Heat treatment, finishing and verification
Specify which operations are included and who is responsible for them. Required records, treatment batches, hardness checks or final dimensional reports should be visible in the quotation rather than added after an order.
Quantity, sample approval and delivery scope
Request separate prices for sample and production quantities when useful. Compare the same finish, inspection, packing and delivery scope, and distinguish a proposed alternative from a change you have approved.
How to start a stainless steel machining order
Send the current drawing
Include the stainless grade, supplied condition, quantity, finish and important application details.
Resolve open specifications
Review feasibility, material alternatives, treatment requirements, inspection and production responsibility.
Approve the quoted scope
Confirm revision, price, sample plan, records and delivery terms before work is released.
Check the parts against the agreement
Use the agreed acceptance criteria and record any approved changes before a repeat order.
Discuss your stainless steel parts with Kevin
I want you to know who is making your parts, what we have agreed to supply and how you can check the result. You should be able to start that conversation without first traveling to China.
Kevin · vetcnc
Our Family and Manufacturing BackgroundI have spent ten years in the CNC industry, following my father’s generation. Our family business grew through exhibitions and long-term customers. We have multiple factories in China, and I am bringing that experience online so new customers can ask practical questions directly.
When a requirement falls outside our factories’ scope, we can discuss an appropriate partner, coordinate the work or make a direct introduction. We agree the manufacturing arrangement before the order, rather than leave you guessing about who is responsible for machining, finishing and inspection.
Questions about stainless steel CNC machining
Which stainless steel grade should I specify for CNC machining?
Start with the approved design and service conditions. Tell us about load, contact fluids, temperature, cleaning and any later welding. The grade and delivery condition should be reviewed against those requirements; an inquiry selection is not an engineering approval.
How do 304 and 316 differ for a machined part?
Is 303 interchangeable with 304 or 316?
What needs to be specified for 17-4 PH parts?
Include the required heat-treatment condition, the material standard and any hardness or mechanical-property requirements. Discuss which state is machined and when final inspection takes place. A grade name by itself leaves part of the requirement open.[4]
Do stainless steel parts need passivation?
It depends on the drawing and service requirements. Passivation addresses surface contamination after fabrication; it is not a universal cure for the wrong alloy or an unsuitable process. Agree the treatment and acceptance method for the actual grade.[6]
Can electropolishing change a fitted dimension?
Yes. It removes surface metal, so include fitted diameters, edges and final acceptance limits in the finishing review. Agree the removal allowance and inspection stage with the processor instead of assuming the as-machined size will remain unchanged.[7]
What tolerance can vetcnc hold on stainless steel?
There is no single tolerance for every grade, size and geometry. Send the critical dimensions, datum system and supplied condition. We confirm the achievable requirements and inspection method for the drawing before making a precision commitment.
Can you machine stainless parts with deep internal passages?
Send the full internal geometry, hole connections and access details. Identify burr-sensitive intersections, cleaning requirements and how the passages can be inspected. Those details need review before feasibility or price can be confirmed.
Can I approve a sample before ordering a batch?
Yes, a sample or pilot plan can be discussed in the quotation. Define the material, finish, inspection and approval criteria, and identify anything intentionally different from the final production part.
Can material certificates and inspection reports be included?
Tell us which records are required when requesting the quote. Confirm material identity, any treatment records, the dimensions to report and the sampling plan. We agree availability and scope for the order rather than assume one document proves every requirement.
Is 316L automatically suitable for food or medical applications?
No material name alone establishes that a complete part is acceptable for a regulated application. Provide the relevant design, cleanliness, traceability and validation requirements for review. This page does not claim a sector certification or application approval.
What should I send for a stainless steel machining quote?
Send the matching CAD model and drawing, grade and condition, quantity, finish, critical dimensions, required records and requested arrival date. Include exposure and cleaning conditions where they affect the part specification.
Request a quote for your stainless steel parts
- Matching CAD model and 2D drawing
- Stainless grade, supplied condition and material standard
- Quantity and current drawing revision
- Final dimensions, surface treatment and exposure conditions
- Sample approval, records and requested arrival date
Agree confidentiality and the transfer method before sharing sensitive or restricted files.
Technical references and material notes
- Carpenter Technology: 303 stainless steel — Grade identity and sulfur addition for machinability.
- Outokumpu: Core 304 and 304L grades — General properties and the low-carbon 304L alternative.
- Outokumpu: Supra 316 and 316L grades — Molybdenum-alloyed grades and corrosion-related selection considerations.
- Carpenter Technology: Custom 630 / 17-4 PH — Precipitation-hardening stainless and condition-dependent planning.
- Sandvik Coromant: workpiece materials — Austenitic stainless machinability, work hardening, chips and tool wear.
- Carpenter Technology: passivating stainless steel parts — Surface contamination, cleaning and grade-specific treatment selection.
- Able Electropolishing: electropolishing and passivation — Difference between chemical contamination removal and surface-metal removal.
These references support general material information, not vetcnc inventory, equipment ownership or certified capability. The approved drawing, material specification and order requirements govern the supplied part. Verify current requirements before release.