MATERIALS / STAINLESS STEEL
Stainless steel turned parts, made to your drawing
CNC turned stainless steel parts from our Dongguan factory, Ø0.5 to 200 mm. Trial runs from 200 pcs, production runs from 2,000 pcs.
- Grades: 304, 303 and 316, with 304 the one we machine most
- ±0.01 mm held as standard
- Finishes we have supplied: electropolishing and passivation and more
- Formal quotation within one working day of a complete PDF drawing
GRADES
303, 304 or 316: which stainless grade to specify
All three are austenitic stainless steels. The differences below are the general properties of the grades as covered by the ASTM bar standards, not a promise for your application. Your designer decides the grade.
- 303 (UNS S30300, ≈ EN 1.4305): sulfur is added so the bar cuts and breaks chips easily. It is the easiest of the three to machine, but its corrosion resistance is lower than 304 and it is not intended for welding. Free-machining bar is covered by ASTM A582.
- 304 (UNS S30400, ≈ EN 1.4301): the general-purpose 18 % chromium, 8 % nickel grade, with good corrosion resistance in most indoor and fresh-water service. Bar is covered by ASTM A276 and A479.
- 316 / 316L (UNS S31600 / S31603, ≈ EN 1.4401 / 1.4404): about 2–3 % molybdenum gives better resistance to chlorides, such as salt water and many cleaning agents. It is tougher to cut than 303, so cycle times are longer.
304 is the grade we machine most, followed by 303, then 316. If a part only needs to be stainless and is not welded or exposed to chlorides, 303 is often the lower-cost choice to machine. Name the grade and standard on your drawing. We can supply the material certificate with your parts, for example a 316L mill certificate to ASTM A479.
All materials we machineA RECENT STAINLESS ORDER
304 stainless banjo fittings, 1,000 pcs
A banjo fitting with a hose barb, turned and milled from 304 bar on one mill-turn setup: the barb and shank are turned, then the ring end is milled and cross-drilled. Drawing and customer stay private; these are the requirements we worked to:
- Ø13 H8 ring bore with a Rz 4 surface, checked with a Ø13.000 plug gauge
- Ø9.5 mm barb diameter, tolerance 0/−0.10 mm, 53 mm overall length
- Cross bore into the ring free of burrs, as the drawing required
- Packed in blister trays so the barbs and bores arrive undamaged
TOLERANCES, FINISHES AND STOCK
Tolerances, finishes and bar stock
Tolerances
±0.01 mm held as standard on stainless parts. ±0.005 mm on a single outer-diameter feature of a part that is not thin-walled, not on combined features. Thin-walled stainless parts are reviewed per drawing. The tolerances on your drawing always govern.
Small stainless parts up to Ø34 mm and 150 mm long can run on our Swiss-type lathes. Swiss-type turning
Finishes
We have supplied stainless parts with electropolishing, passivation, bead blasting, brushed finish and black oxide for stainless steel. State the finish, and any standard it must meet, on the drawing.
Bar stock
We keep common 303 and 304 bar sizes in stock; other grades and sizes are bought for your order.
QUALITY
How stainless parts are checked
- First-article check of every dimension on the drawing, for every order.
- Critical bores and diameters are checked with their own gauges during the run, as with the plug gauge above.
- Parts that do not meet the drawing are replaced or refunded free of charge, with freight both ways paid by us, if reported within 30 days.
YOUR STAINLESS PART
Send your stainless steel part drawing
A PDF drawing with dimensions, tolerances, grade and finish, plus the quantity, is enough for a quotation.