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PRECISION GROUND RODS · SPECIALTY GRINDING
Thick-Wall Tubing & Hollow Bar OD Grinding
Specialized OD processing for heavy-wall mechanical tubes and hollow bars destined for sleeves, shafts, machined housings and engineered components.
PROCESS & MATERIAL SELECTION
What this grinding request involves
A thick-wall tube or hollow bar can reduce machining time versus drilling from solid, but OD grinding must still respect minimum wall, bore straightness, eccentricity and downstream machining allowances. Hollow bar is not automatically interchangeable with pressure-rated pipe. The supplied product form and service requirements govern specifications.
Applications and available processing routes are reviewed against your drawing. A page discussing a material or service does not promise stock availability, a universal tolerance, or acceptance of every tube geometry.
SUPPLY & PROCESSING
Before quoting
Identify the tube or bar construction, exact grade and starting condition. Specify the outside diameter before and after grinding, length, quantity, required surface finish, and straightness or concentricity requirements.
TOP GRADES & STANDARDS
Material grades, product specifications & heat treatment
Examples for purchasing discussion—not blanket claims of availability or certification. Verify the correct ASTM edition, form, ordered condition and mill test report.
| Grade / product | Relevant specification | Supplied / heat-treated condition | Grinding review |
|---|---|---|---|
| 1026 / 1045 carbon hollow stock | ASTM A519 where certified | Hot-/cold-finished, normalizing by order | Bore offset and available wall |
| 4130 / 4140 / 4340 alloy tubing | ASTM A519 where certified | Annealed, normalized or Q&T as specified | Hardness and concentricity |
| 304 / 316 / 316L stainless hollow bar | ASTM A511/A511M | Austenitic annealed | Seamless hollow machining stock |
| 17-4 PH specialty hollow section | Grade/product-form-specific certification | Condition A or aged condition if supplied | Do not assume common bar specification covers tube |
| 52100 bearing-grade tubular blank | Certified alloy/product-form spec | Spheroidized or hardened per order | Heat-treat distortion and residual wall |
Material heat treatment, mechanical testing and pressure/structural suitability are governed by the original applicable standard and purchase requirements.
SUPPLIED CONDITION
Heat-treatment conditions to verify
A heavy-wall hollow section may be supplied hot-finished, cold-finished, annealed, normalized or quenched and tempered according to alloy and specification. 17-4 PH hollow components require an explicit product specification and certified precipitation-hardening condition. Check wall after any OD removal and before further ID machining.
If the drawing calls for hardness, tensile properties or treatment after grinding, include it explicitly in the RFQ. Finishing does not itself establish a new certified heat-treated condition.
COMMON RFQ FIELDS
Quote-ready information
- Starting OD, bore ID and minimum required finished wall
- OD-to-ID concentricity, runout and inspection datum
- Heat-treatment condition and hardness
- Machining allowance, finished length and handling/packaging
ENGINEERING & PURCHASING QUESTIONS
Questions buyers ask
Is hollow bar the same as DOM tubing?
Not always. Hollow bar can be seamless heavy-wall stock or another certified form. DOM identifies a specific welded-then-drawn process.
Can OD grinding guarantee bore concentricity?
Only with a defined datum, process and measurable tolerance agreed at quotation. OD grinding by itself does not correct every internal eccentricity.
Why provide minimum finished wall?
Grinding away OD reduces the available cross-section, which can matter for strength, fit and downstream machining.
QUOTE BY GRADE, SIZE & FINISH
Have a tube or oversized bar that needs OD grinding?
Send the material grade and product standard, incoming and finished dimensions, condition, wall or bore details where applicable, length, quantity and any surface, inspection or documentation requirements.