Tap and Thread
A tap is a tool for creating internal threads in holes. You can tap or thread holes or protrusions in your part. For example, you might tap a hole for a bolt or thread a protrusion to mate with another part.
To tap holes or thread protrusions:
- Select a circle.
- Choose Line | Machine | Thread.
- Thread system – Inch/Metric/Taper – select one or click User defined (see below).
- Thread settings grid – choose the desired thread from the Size column to match the intended screw or nut.
- Threads are right hand by default. Use Comments to Machinist to specify Left Hand.
- Set the thread length in the toolbar Z control. The maximum thread length is slightly less than the drill depth. Enter the length of fully formed threads (measured from the "near" edge) or check Maximum.
- To also thread from the opposite view (e.g. both ends of a rod or hole), select the opposite view and apply the thread feature again.
Note: You will see a small floating disk in the 3D view to remind you that the adjacent region is threaded.
It is impractical to machine threads fully to the bottom of a hole or to the end of a boss on an external thread. Therefore, depending on the design, for an external thread that ends at a boss (a larger diameter) it may be necessary to create a groove (replacing ~3 threads) so that a mating part seats properly.
The CAD software will automatically create two concentric circles and parts will be machined to the indicated thread size according to the Unified Thread Standard specs.
If you have a male and female component, use the exact same thread spec for each.
Edit thread length using theZ Axisedit control on the numeric bar.
Threading with Revolve
User Defined Threads
To specify values not shown on the grid:
- Select User Defined.
- In Size enter the major diameter. For example for a 1/4-20 you would enter .25". For a metric M10 you would enter 10mm. You can enter larger values such as 3" for such applications as lens mounts.
- In TPI enter number of threads per inch. For example for a 1/4-20 you would enter 20.
To specify more exotic threads and taper pipe threads not on the grid:
- Draw a circle of the minor diameter (or slightly smaller if you don’t know the minor diameter)
- Use Comments to Machinist to describe the desired thread.