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Thread

Put a screw thread on a round face, inside a hole or round a shaft: cosmetic for drawings, or modelled for 3D printing.

  • Thread AdvancedPart Studio toolbar
What other CAD programs call it
SchoolCADOnshapeFusionSOLIDWORKS
Thread–ThreadThread
Cosmetic Thread

Thread puts a screw thread on a round face of a part: the inside of a hole (an inside thread, like a nut) or a round shaft (an outside thread, like a bolt). It reads the size from the face, so a 5 mm hole becomes an M6 thread (5 mm is the tap drill for M6) and an 8 mm shaft an M8 thread. It works like Thread in Fusion and SOLIDWORKS.

A thread can be cosmetic or modelled:

  • A cosmetic thread only marks the face as threaded. Engineering drawings show it the way industry does (a thin three-quarter circle, and a callout such as M6 × 1). Use it for parts made in the workshop, where a tap or die cuts the real thread.
  • A modelled thread is cut into the part: the real ISO 60° thread, ready to 3D print, so a printed part takes a real bolt or nut, or two printed parts screw together.

Thread is an Advanced tool. For a tapped hole, the Hole tool can make the thread too.

How to use it#

  1. Make the part with a round hole or a round shaft. For an inside thread, make the hole the tap drill size (Ø5 for M6, Ø6.8 for M8): the Hole tool's Tapped type does this for you.
  2. Click Thread.
  3. Click the round face: the inside of the hole, or the side of the shaft. The dialog says what it found, such as Outside thread M8 × 1.25, 25 mm long.
  4. Change the Size, Length or Hand if you need to.
  5. Tick Modelled thread to 3D print it.
  6. Click ✓.

Options#

OptionWhat it does
FaceThe round face, and its diameter. Click another round face to thread that one instead.
SizeTo fit the face picks the ISO metric size the face fits. Or choose a size (M1.6 to M24), or Custom.
Major Ø / PitchCustom only: any diameter and pitch, such as a jar lid: Ø60 with a 3 mm pitch.
PitchThe coarse pitch (the usual one) or a fine pitch (ISO 261), such as M10 × 1.25.
LengthFull length: the whole face. Or untick it and type how long the thread is.
OffsetHow far from the end the thread starts, in mm.
StartThe thread starts at the open end of the face (the top of the hole, the end of the shaft). ⇅ From the other end starts it at the other end.
HandRight hand (almost every screw and bolt) or Left hand (the left pedal of a bike, gas fittings).
Starts1 to 4. A thread with two or more starts goes in faster (a jar lid often has two).
Modelled thread (for 3D printing)Off: a cosmetic thread. On: the real thread is cut.
Print fitModelled only: extra room in the thread, in mm, so a 3D print does not bind. 0.1 to 0.3 mm suits most printers.

Tips#

  • A modelled thread runs right out through an open end, as a tap or a die leaves it, so the bolt starts easily.
  • Modelled threads are heavy (thousands of triangles). Add them last, after the rest of the design is done.
  • For an inside thread, the hole should be the tap drill size. If it is not, the dialog says what it should be.
  • To 3D print a nut and bolt that fit each other, model both with the same size and pitch, and give one of them a Print fit of 0.2 mm.
  • A thread that is not ISO metric (a jar lid, a bottle cap) is a Custom size.
  • For a spring, or a thread that is not on a round face, use Coil.

If it does not work#

  • Click the round face to thread: the inside of a hole, or a shaft. Click the curved side of a round hole or a round shaft. Flat faces and faces that are not round all the way along cannot be threaded.
  • The hole (Ø6) is as wide as an M6 thread. Drill the hole at the tap drill size (Ø5 for M6), or choose a bigger thread.
  • The shaft (Ø5) is too thin for an M8 thread. Make the shaft the size of the thread (Ø8 for M8), or choose a smaller thread.
  • The face has other holes or cuts across it where the thread goes, so it cannot be modelled. A modelled thread needs a plain round face. Move the Thread above the feature that cuts across it, or use a cosmetic thread.
  • The round face to thread has gone. An earlier change took the face away. Edit the thread and click the face again.