Tap and Thread
A tap is a tool for creating internal threads in holes. A lathe is often used for external threading of protrusions. 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.
- Length of fully formed threads - enter the length of fully formed threads (measured from the "near" edge) or check Maximum Permitted By Standard Tap. (For internal threads this length indicates the depth of threads in a hole before the threads taper off due to the taper that occurs in thread tapping tools; or the longest screw that can be used in a threaded hole. For external threads this length indicates how much length of a cylindrical surface is to be threaded.) For example, at 20 threads per inch, one inch of fully formed threads would create 20 fully formed threads.
- Threads are right hand by default. Use Comments to Machinist to specify Left Hand.
- Note: The software will choose automatically whether the thread is internal or
external.
Note: You will see a small floating disk in the 3D view to remind you that the adjacent region is threaded.
Note: To add tapping or threading with the Revolve feature use Comments To Machinist.
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.
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 as proper clearance will automatically be machined.
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.
Also see Unified Thread Standard.
Tip: You can edit the Z depth/length using the Z Axis edit control on the numeric bar.
