milling & Turning

Applicable Standards

• ISO 2768 for general tolerances

• ISO 286 Limits and Fits

• ISO 21920 Surface Finish

Material Specifications

The material type and grade stated on the Fractory platform is what should be followed even if alternative materials are shown on the production drawings attached. If anything is unclear please ask the account manager associated with the job.

Unless otherwise specified the surface condition and visual appearance of the finished part should be in line with class B+ Finish as specified in the  "General Appearance" section of this handbook.

Please see below images showing examples of a Class B+ finish for machined parts:

Dimensional and Geometrical Tolerances

Please note that any tolerances specified against each individual part on the Fractory platform take precedence over any tolerances stated on the production drawing provided unless otherwise specified. Unless otherwise specified standard machining tolerances should be in line with Class B as defined in the below table.

*NOTE* Some parts may require dimensional tolerances that are tighter than Class A (eg. Limits and Fits in line with ISO 286). In these cases it will be identified on the Fractory Platform and would need to be agreed up front.

Hole Treatments, Threading & Special machining finishes

Please refer to any attached production drawing for details of tapping, threading and any special machining finishes (eg. Knurling). these details will often not be included on the STEP file.

Inspection and acceptance

Parts should be checked against the drawing for dimensional accuracy and against this document for quality acceptance before shipping parts.

From time to time we may ask for quality images or documents to be uploaded to prove the parts meet the required quality standards before they can be shipped.