At O’Hare Precision Metals, we’ve been supplying precision-ground and cold-finished round steel bars since 1970. Every bar that leaves our Arlington Heights, IL facility goes through a defined, inspected process. Understanding that process helps you specify correctly and source with confidence.
Buyers often focus on the finished diameter and surface finish. What matters just as much is how those results are actually achieved. From raw stock selection through final packaging, each step in our process is deliberate, in-house, and backed by ISO 9001:2015 certified quality control at every phase.
The Complete Manufacturing Path from Raw Stock to Finished Precision Bar
Raw mill stock and a finished precision-ground bar look like two completely different products. The difference is the process connecting them. Each operation we run in-house removes a variable that would otherwise show up as a rejected part, a failed tolerance, or a surface that doesn’t meet your print.
Every material we process moves through this sequence at our Arlington Heights facility. Stainless steels, alloy steels, carbon steels, tool steels, aluminum, brass, copper, bronze, titanium, and nickel alloys all follow the same disciplined path. The grade changes. The process discipline does not.
Raw Material Selection and Incoming Inspection
Every job starts with the incoming stock. Before any bar enters the process, it goes through quality control inspection. The grade, condition, and end application all factor into how we evaluate it. A bar intended for a surgical implant application gets handled differently than one going into a mechanical drivetrain component.
Getting raw material selection right protects every downstream operation. Poor incoming stock produces inconsistent results, no matter how well the grinding is set up. We apply tough raw material standards from the beginning because fixing a problem at the source is far less costly than finding it after machining is complete.
Straightening Before Grinding
Mill stock comes with variation. Bow and camber in a raw bar create problems the moment it enters a centerless grinder. The wheel cuts unevenly, the diameter varies along the length, and the surface finish becomes impossible to control. Straightening removes that variable before grinding begins.
This is an in-house step that doesn’t show up on the finished certificate, but it directly determines whether the grinder can do its job. Skipping it makes holding tolerances along the full bar length unreliable. We run straightening as a standard step, not an optional one.
Centerless Grinding to Tolerance
Centerless grinding is the core of our operation. The bar rests on a work rest blade between a grinding wheel and a regulating wheel. Wheel speed, feed rate, and workpiece positioning are controlled throughout the cycle. We hold tolerances up to .0001 inches and achieve surface finishes of 8 micro inches or better.
Our capacity covers diameters up to 9 inches and lengths up to 50 feet. The specialized grinding division handles up to 7 inches in diameter and 24 feet in length. We run in-feed and through-feed grinding depending on geometry and job requirements. CNC rotary dressers handle intricate radii, profiles, and spherical radii. In-process gauging runs during the cycle to catch any drift before it affects the full run.
Saw Cutting to Required Length
Once a bar is ground to diameter, cutting to length comes next. We use cold saw blades, which produce clean, smooth cuts with minimal waste and low surface roughness at the cut face. Cold sawing consistently outperforms friction sawing, hot sawing, and bandsawing in dimensional consistency and cut quality.
Automated CNC saws handle diameters up to 7 inches. Specialized saws designed for shorter bar lengths reduce vibration during the cut, which protects the ground surface finish on the rest of the bar. Manual and power bar saw options are also available, depending on the job requirements.
Turning for Cylindrical Surface Requirements
Turning generates cylindrical surfaces and reduces the workpiece diameter to a specified dimension. It works across stainless steel, aluminum, and customer-specified alloys, handling both short and long pieces at varying diameters. We use center and face drills for longer pieces to maintain accuracy through the full length.
Every turning job balances three variables: tool life, metal removal rate, and surface finish. Controlling all three together is what keeps the part within tolerance and cost predictable. Turning is available as a standalone operation or as a complement to centerless grinding, depending on what your geometry requires.
Milling for Complex Part Features
Some parts need more than a ground round profile. Milling produces flat surfaces, slots, holes, pockets, and cutouts. We run horizontal, universal, drum-type, and vertical mills in both manual and CNC configurations. Materials include stainless steels, aluminum, carbon steels, alloy steels, and copper.
Milling tolerances reach (+/-)0.0001 inches depending on geometry and material. For parts moving from raw bar to a near-finished state in one facility, this matters. Combining grinding and milling in-house at Arlington Heights eliminates handoffs between vendors and keeps your timeline tighter.
Chamfering, Burnishing, and Polishing
Sharp edges on a precision-ground bar create handling risks and stress concentration points during downstream machining. Bar chamfering removes excess metal to create symmetrical sloping edges. We run CNC and manual chamfering with multiple continuous drawing machines on site for undercuts, V-cuts, welding preparation, and deburring.
Burnishing uses controlled plastic deformation to create compressive residual stress, close porosity, and combat fatigue failure without removing material. Roller burnishing handles outside diameter shafts, inside diameter holes, tapers, fillets, and spherical contours. Polishing is available for stainless steel, brass, copper, bronze, titanium, and aluminum using centerless polishing cells, bar and tube polishers, buffing cells, automated belt sanders, and linear pipe polishing cells.
Quality Control and Final Packaging
Inspection at a single endpoint catches problems too late. Our quality control runs at each phase of operation, from incoming material through every machining step. We’re ISO 9001:2015 certified, and that certification reflects a documented system where nothing moves forward without verification.
Packaging protects everything that the process produces. Options include individually wrapped tubes and collars, paper wraps in bundles, and custom wood boxes. We also accommodate custom packaging per customer preference. The bar that leaves our facility at the specified tolerance and finish arrives at your dock in exactly that condition.
FAQs
What tolerances can you hold on precision ground bar?
We hold tolerances up to .0001 inches with surface finishes of 8 micro inches or better on centerless ground round bar stock.
What is your maximum grinding capacity?
Centerless grinding covers up to 9 inches in diameter and 50 feet in length. The specialized division handles up to 7 inches in diameter and 24 feet in length.
Do all operations run in-house?
Yes. Straightening, grinding, turning, milling, saw cutting, chamfering, burnishing, polishing, and packaging all run in-house in Arlington Heights, IL.
What materials do you process?
We process stainless steel, alloy steel, carbon steel, tool steel, aluminum, brass, copper, bronze, titanium, nickel and high temperature alloys.
Get a Quote for Your Precision Ground Bar Requirements
Call us at (847) 640-6050, email sales@ohareprecision.com, or submit your specification through our Request a Quote form. We’re available Monday through Friday, 9:00am to 5:00pm CST.