If you run a CNC turning operation near Chicago, bar stock selection decides your cycle time and tool life. The wrong grade costs you inserts. The wrong supplier causes downtime. O’Hare Precision Metals has supplied precision-ground and cold-finished round steel bars to manufacturers since 1970, and 303 stainless steel is one of our most requested grades for turning work.
303 is an austenitic stainless steel known for good machinability. That makes it the natural choice when your shop runs nuts, bolts, and gears at volume. It carries the corrosion resistance and durability of the austenitic family, so you’re not trading performance for machinability. You get both in one grade.
Why 303 Stainless Steel Round Bar Works for CNC Turning
303 sits in the austenitic stainless family alongside grades like 304 and 316. What separates it is machinability. Your tools stay sharper longer, your cycle times stay consistent, and your scrap rate stays lower. For high-volume CNC turning of threaded parts and gears, that combination is hard to beat across a full production run.
The grade also holds up in corrosive environments, which matters when your finished parts go into food and beverage, medical, or industrial assemblies. You get a material that machines cleanly on the floor and performs reliably in the field. That’s the practical reason 303 keeps appearing on print callouts across Chicago area shops.
Why Bar Stock Condition Changes Your Results
Bar stock that arrives with diameter variation forces your lathe to compensate on every pass. Precision ground bar eliminates that problem. We hold tolerances up to .0001 inches on centerless ground bar, with a surface finish of 8 micro inches or better. Your finish pass has less corrective work, and your tool life stays predictable across the full run.
Cold-finished round bar is another option when your print requires improved surface condition and closer dimensional control. The right choice depends on what your tolerance callout actually demands. Include your diameter, tolerance, and finish requirement in your quote request, and we’ll match the correct bar condition to your program from the start.
How We Grind 303 Round Bar at Our Arlington Heights Facility
Centerless grinding is what we’ve built our facility around. The process removes material using abrasive cutting without a centering device, which produces precise concentricity and a smooth surface finish on the cylindrical bar. We control wheel speed, feed rate, and workpiece positioning to hold tight tolerances on stainless grades, including 303.
Our grinding capacity covers diameters up to 9 inches and lengths up to 50 feet. Our Specialized Grinding Division handles up to 24 feet in length at up to 7 inches in diameter. CNC rotary dressers handle intricate radii and profiles, and in-process gauging runs during the grinding cycle, so dimensional verification is built into the process.
Companion Services That Complete Your Order
Most customers need more than a ground bar alone. Our CNC automated saws cut up to 7 inches in diameter using cold saw blades that produce clean, smooth ends with minimal waste. Shorter cut lengths arrive ready for your turning program without extra prep work on your end before the material hits the chuck.
Bar chamfering is available on site, both CNC and manual, covering undercuts, V-cuts, weld preparation, and deburring. Packaging is handled carefully as well. We offer individually wrapped tubes and collars, custom wood boxes, and paper wrap in bundles, with custom options per your preference. Your bar arrives in the same condition it left our facility.
Other Stainless Grades We Carry
303 is our machinability pick, but it’s one grade in a deep stainless inventory. We also stock 302, 304, 304/304L, 316, 316/316L, 316LVM, 321, and 347 in the austenitic family. Martensitic grades 410, 420, and 420F are available, along with ferritic grades 430 and 430F, and precipitation hardening grades 15-5PH and 17-4PH.
If your engineer is still deciding between grades, we’ll give you a straight answer on what fits your application and what doesn’t. We carry duplex stainless and bearing shaft quality bar as well. The goal is always to match the right material to your actual requirements, not to push whatever is easiest to move off the shelf.
Quality Standards Behind Every Bar We Ship
We are ISO 9001:2015 certified. Quality control inspections run at each phase of operation, from raw material through grinding and any secondary services, before your order ships. For manufacturers supplying regulated industries, that certification supports your vendor qualification process and keeps your documentation trail clean from the start.
Our quality process isn’t a final inspection step added at the end. It runs continuously through each operation, so problems get caught early, not after the bar is already ground and cut to length. That’s the practical difference between a certified process and a piece of paper that says certified on it.
Request a Quote from O’Hare Precision Metals
Since 1970, O’Hare Precision Metals has delivered on our core promise: Superior in Steel Production and Machining Operations. Send us your diameter, tolerance, length, and finish condition, and we’ll build a quote around what your CNC turning program actually needs. Our team knows what questions to ask when your requirements need a closer look.
You can reach us through the Request a Quote form at ohareprecision.com, call us at (847) 640-6050, or email us at sales@ohareprecision.com. We’re available Monday through Friday, 9:00 am to 5:00 pm CST. The sooner you send your specs, the sooner we can get your material confirmed and moving toward your floor.
FAQs
Q: Is 303 the right grade for every CNC turning job?
A: Not always. 303 suits nuts, bolts, and gears where machinability leads. If corrosion resistance is the priority, 316 may fit better.
Q: What tolerances and finishes are available on 303 round bar?
A: We hold tolerances up to .0001 inches with a surface finish of 8 micro inches or better. Include your print requirements when quoting.
Q: Can you cut the 303 round bar to our required lengths?
A: Yes. Our CNC automated saws cut up to 7 inches in diameter and produce clean, smooth ends. Specify lengths in your quote request.
Q: Does your ISO certification cover grinding and secondary operations?
A: Yes. ISO 9001:2015 covers our full process. Quality control inspections run at each phase, including grinding, chamfering, and packaging.