Reference Section > Shape Library > Primitives

The Disk/Hole shape is a single circle of a given diameter, centred on the insert point. On its own it is a round disk; placed inside another profile it is a round hole. It can also carry one or more keyways cut outward from the circle, which turns a hole into a keyed bore for a shaft.

It appears in the shapes library under Basic Shapes, Round Shapes and Primitives.

Insert point and direction

The centre of the circle is the insert point (Base X, Base Y). The circle is built anticlockwise. With a keyway the profile is one closed path, also anticlockwise: out along one wall of each keyway, across its square end, back along the other wall, then round the bore to the next keyway.

The Diameter dimension is drawn across the circle. With a keyway, Key Width is dimensioned across the end of the first keyway and Key Depth along its centre line.

Properties

Property	Description	Default
Diameter	Diameter of the circle (mm or inch). With Keyway set to None, a Diameter of 0 gives a single point at the insert point instead of a circle; the shape does not reject a negative Diameter, so do not enter one. With a keyway, a Diameter of 0 or less cannot be built.	100 mm (4 in)
Key Depth	How far the keyway goes beyond the circle, measured on the keyway centre line from the circle to the end of the keyway (mm or inch) – the hub depth t2 of DIN 6885, so the hub measures Diameter + Key Depth. Must be greater than 0. Used as entered for Custom; replaced by the standard value for Metric and Inch.	2.5 mm (0.1 in)
Key Width	Width across the keyway (mm or inch). Must be greater than 0 and less than the Diameter. Used as entered for Custom; for Metric and Inch it is replaced by the standard value when the shape is built.	6.25 mm (0.25 in)
Keyway	Adds keyways cut outward from the circle, so a Disk/Hole used as a hole becomes a keyed bore. None – plain circle; Custom – Key Width and Key Depth as entered; Metric (DIN 6885) – width and depth taken from DIN 6885-1 for the Diameter; Inch (ANSI B17.1) – width from ANSI B17.1 (square key) for the Diameter, depth worked out from it.	None
Keyway Angle	Direction of the first keyway centre line, anticlockwise from +X (degrees).	90° (straight up)
Keyway Count	Number of keyways, spaced evenly round the circle starting at Keyway Angle. Minimum 1, maximum 1000. Neighbouring keyways must not overlap.	1

Key Width, Key Depth, Keyway Angle and Keyway Count have no effect while Keyway is None. Parts saved before the keyway was added open with Keyway set to None and keep their plain circle.

The keyway dimensions are shown only while Keyway is not None and the keyway is valid. With a keyway, Key Width is dimensioned across the end of the first keyway and Key Depth runs along its centre line from the circle to the end of the keyway.

Standard keyways

With Metric (DIN 6885) or Inch (ANSI B17.1) the keyway size is looked up from the Diameter each time the shape is built, and written back into Key Width and Key Depth so you can see the values used.

•Metric covers bores over 6 mm up to 500 mm. Both width and depth come from the table.

•Inch covers bores over 5/16 in up to 6 1/2 in. The table gives the key width. The keyseat is half the square key deep at its side walls; Key Depth is that depth on the centre line, i.e. half the key width less the height of the bore arc across the keyway.

When the shape cannot be built

If the values cannot make a valid shape, the shape is not drawn, a broken-shape marker is shown at the insert point, and the property page shows Warning: Cannot build shape from these parameters. With a keyway this happens when:

•Diameter is 0 or less (a keyway needs a bore greater than zero);

•Keyway is Metric or Inch and the Diameter is outside the range of the table;

•Keyway Count is less than 1 or more than 1000;

•Key Width is 0 or less, or is not less than the Diameter;

•Key Depth is 0 or less;

•there is more than one keyway and neighbouring keyways overlap – use fewer or narrower keyways.

Every 2D shape also has the Transform properties (Base X, Base Y, Rotation, Scale, Mirroring X) and the Polar Array properties, listed after the shape's own properties.