Machining Tolerance

Machining tolerance means the dimension range that can be meet by CNC Machining, Machining tolerances may be affected by a number of factors. such as fixture design & produce, raw material, machining equipment & cutters, inspection equipment, and workers skill. The machining tolerance varies from factory to factory. Some factory may be specialized in small aluminum parts, and others could be more professional in machining stainless steel parts.

Generally, Machining tolerances can be divided into Linear Tolerances and Geometric Tolerances. If not specified, We follow ISO 2768 standard to produce the machined parts, we can reach ISO2768-m & ISO2768-f standard.

CNC Turning Tolerance:

Linear tolerance: Machining tolerance grade: IT 6-7

Flatness: Machining tolerance grade: IT 5-6

straightness: Machining tolerance grade: IT 5-6

Cylindricity:Machining tolerance grade: IT 5-6

Surface roughness:  For Turning process, we can reach Ra 0.8- 3.2 for metal material, Ra 0.4-1.6 for plastic material. For facing process, we can reach Ra1.6-6.3 for metal material and Ra 0.2-0.8 for plastic. For Boring process, We can reach Ra 0.4-0.8 for metal and Ra0.2-0.4 For plastic.

CNC Milling tolerance:

Linear tolerance: Machining tolerance grade: IT 6-10

Flatness: Machining tolerance grade: IT 7-8

Straightness: Machining tolerance grade: IT 7-8

Surface roughness: Ra 0.8-3.2

international Tolerance (IT) Grades table
International Tolerance (IT) Grades table

Investment Casting Tolerance

To get stainless steel casting parts, the best way is to use investment casting process. Our company machining a lot of casting parts every year, so Investment casting tolerance is also quite important to us.

Investment casting casting tolerance table


As a precision machining shop, We specialized in machining custom stainless steel machined parts. Machining critical components to Industry-leading companies have shown our Precision machining ability and tight machining tolerance.

If you want more information about our machining/casting/welding/forging tolerance, please feel free to contact us.