The practical points
TG&P combines turning, grinding, and polishing when the job needs a controlled diameter, geometry, and surface route.
Centerless ground bar is appropriate when diameter, roundness, finish, or straightness targets require it.
Cold drawn bar can be the practical answer when standard commercial tolerances fit the job.
Choose the least-complex route that satisfies the process
| Route | Consider it when | Confirm before ordering |
|---|---|---|
| Cold drawn / cold finished | Commercial dimensional and surface capability fits the setup and finished-part plan. | Actual size range, straightness, surface, condition, length, and source capability. |
| Turned, ground & polished (TG&P) | The requirement calls for a sequential turning, grinding, and polishing route to control diameter, surface, and geometry. | Starting stock, final diameter range, roundness, straightness, surface-finish target, stock-removal allowance, length, and inspection method. |
| Centerless ground | Diameter, roundness, surface finish, straightness, or exposed-stock features justify the conversion. | Starting stock, finished diameter range, grind allowance, length, end condition, burn/decay controls where applicable, and inspection. |
Avoid both under-specifying and overbuying
Ground stock can solve a real geometry or surface problem, but a blanket “Swiss always needs ground bar” rule can add cost and sourcing time without solving the actual cause. Conversely, ordering a generic cold-finished bar when the guide, collet, unattended run, or unmachined outside diameter needs a controlled window can move cost onto the shop floor.
A five-question decision
- Is any stock outside diameter left on the finished part?
- What incoming diameter range and cross-sectional form can the setup accept?
- What straightness and surface condition does the feeder/guide arrangement require?
- What did successful and unsuccessful heats actually measure?
- Which conversion route can document the requirement at the needed quantity and date?
Define the geometry before selecting the finish, then place the complete requirement in the round-bar RFQ template.
Put it on the purchase description
If diameter tolerance, straightness, roundness, surface finish, hardness, chemistry, origin, or documentation can affect acceptance or machining performance, state it explicitly. A familiar grade name is not a complete purchasing specification.
Reviewed by the Exact Bar technical sourcing team. Last reviewed August 17, 2026. The review checks primary sources, separates grade-specific claims from general guidance, and identifies what still requires machine, print, source, or lot validation. This is procurement guidance—not permission to substitute material or bypass the drawing, purchase order, accepted quote, order acknowledgement, incorporated specifications, or machine-specific validation.
Primary sources
Review the Exact Bar sourcing desk options when the requirement also involves quantity, cut length, timing or material documents. Confirm the proposed source and commitments in the written quote.
Carry the finish decision into a grade-specific enquiry
A processing-route choice does not settle grade identity or condition. Continue to the relevant material page before preparing the requirement:
- 1144 steel round bar: state any named-product or source restriction and the required condition.
- 303 stainless round bar: separate required incoming geometry from heat-specific machining observations.
- 316 / 316L stainless round bar: identify the grade required by the drawing and its documentation requirements.
Send the combined grade-and-finish requirement for review, including the accepted dimensional range, quantity, lengths and required date. Ask for unresolved capability or inspection questions to be addressed in the written offer.