HUASHENG PRECISION · Updated September 11, 2026
Machining Tolerance Checklist: Define What Your Part Needs
A useful tolerance comparison starts with the feature and its function. Use this drawing-review table to define dimensions, datums, inspection and finishing before asking a supplier to confirm capability.
Comparison and drawing review
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| Requirement | What to specify or discuss |
|---|---|
| Milled pockets and faces | State size, depth, corner radii and flatness or profile requirements; distinguish free-state from restrained inspection. |
| Turned diameters and bores | Identify fits, roundness or runout where required, datum relationships and the measurement location. |
| Holes and threads | Give position requirements, datum references, usable depth, thread standard and the agreed inspection method. |
| Bent sheet-metal parts | Specify material, thickness, bend direction, inside radius and the dimensions important after forming. |
| Plastic machined parts | State grade, stock condition, critical assembly dimensions and any conditioning or measurement requirements. |
| Coated or finished parts | Identify dimensions before and after finishing, masked surfaces and the specified finish thickness. |
Dimension tolerance and geometric tolerance answer different questions
A size limit does not by itself control the location or orientation of a feature. For a mating assembly, identify the actual datum system and the relationship that must be measured. Send the drawing with its governing dimensioning standard and revision; do not replace specific callouts with an informal tolerance promise.
Use a fit requirement, not the tightest number everywhere
Separate functional interfaces from cosmetic or clearance features. A tighter requirement can change tooling, setups and inspection time. Ask the designer which dimensions can be relaxed without changing function; any proposed change needs written approval before manufacture.
Agree how the result will be accepted
List the critical features, sampling or full inspection requirements, report format and measurement conditions. A measuring instrument specification alone does not prove that every feature on a part can be produced or verified to the same value. Confirm access for the probe or gauge and the condition of the part during inspection.
What our quotation should confirm
The review should state accepted drawing requirements, any proposed exceptions, the inspection scope, processing sequence and delivery terms. If a tolerance has not yet been assessed, it remains an open item rather than an automatic manufacturing commitment.
Workshop information
Our company presentation records a 7,000 m² facility in Dongguan, 35 CNC machines and 170 employees. Manufacturing, inspection and any required partner processing are reviewed against the drawing and order requirements.
If a certification or specific document is required, identify its scope before quotation.
Company and equipment informationShipping method, freight, duties, taxes and customs arrangements are confirmed by email for each order, based on the destination and order details.