Machining Bluntstart and Quickstart threads with live tooling in GibbsCAM.

MillBlunt are a free stand-alone plugin and allows you to very quickly generate 3D geometry for milling away any incomplete threads after threading.

MillBlunt generates helixes in all the main coordinate systems on a millturn or a lathe with live tooling. Tested in-house during development for over 4 years, method is applied to hundreds of threads.
Its basically a very fast and easy to use parametric helix geometry generator, tailored specifically for threads.

• Easy control of adjusting shape of the blunt, out in a sloped line or with an arc.
• Supports geometry for righthand / lefthand and both ends of an external and internal threads in YZ Plane and XY Plane.
• Option to store all MillBlunt data inside the GibbsCAM file, for loading back and change/redo later.
• Online documentation accessible directly from the plugin.
• Supports segmented geometry to force post-processor to output 3 axis simultaneous G1 moves, which can be advantageous on older machine controllers.
• Autodetects GibbsCAM environment (Inch/Metric)

New in v2.0:

• Option to read data from an existing lathe threading operation and autofill needed thread values directly into MillBlunt for machining Blunt Start and Blunt End.
• Option to read data from an existing MillBlunt contour operation back into MillBlunt for a quick edit.

A great tool to have in your arsenal. It also offers as an quick alternative to the built in Helix Builder in GibbsCAM.

With its very quick setup time, MillBlunt in GibbsCAM will make all your threads look like a thread gage.

24.03.2022 - MillBlunt v2.0 - Rework of the entire plugin. Tabbed interface and lots of improvements and a few new features to improve workflow.

23.03.2023 - MillBlunt v2.2 - Added support for multispindle. Select to create geometry in the main spindle or sub spindle from the interface.

28.12.2025 - MillBlunt v2.3 - Fixed error about 'Could not calculate the Process' that occur in GibbsCAM 2025/2026.

28.03.2026 - MillBlunt v2.4 - Improved and faster geometry creation, online update available directly from GibbsCAM.

Blunt start thread Per ASME B1.7-2006 Definitions:

Blunt start thread: a thread with removal of the incomplete thread at the starting end.
This is a feature of the threaded parts that are repeatedly assembled by hand, such as hose couplings and thread gages, to prevent cutting of hands and crossing of threads.
Also known as Higbee cut or a convoluted thread.

MillBlunt can also generate all kinds of parametric helix geometry in multiple coordinate systems to be machined with live tooling.