Thread turning

External thread turning

External thread turning is often easier and less demanding on the tool than internal thread turning and there are a number of different methods which can be used to achieve the desired results.

To consider for external thread turning:

• The feed rate must be equal the pitch of the thread
• Choose an adequate number of thread cutting passes and depth of cuts
• Chip formation, to avoid chips clogging around the tool and/or component
• Avoid vibration caused by long tool overhangs and slender components
• Tool alignment and centre height

Internal thread turning

Internal thread turning is more demanding than external thread turning, due to high need of efficient chip evacuation and that the tools often need to be longer and more slender.

To consider for internal thread turning:

• Chip evacuation, especially in blind holes, is helped by using left-hand tools for right-hand threads and vice versa (pull-threading). However, this also creates higher risk of insert movement
• Use modified flank infeed to generate a spiral chip, which is easy to guide towards the entry of the bore
• Choose an adequate number of thread cutting passes and depth of cuts
• Avoid vibration caused by long tool overhangs
• Tool alignment and centre height
• If a long tool is needed for reach, use a carbide or dampened tool to minimize vibrations

Tool alignment and centre height is
important for a good threading process