Generates knobs for trimmers/potentiometers/rotary encoders. The design is highly customizable. Both board-mount trimmers (screwdriver-adjusted) and stemmed potentiometers are supported.
To generate knobs with hatched knurling on the knob then the KnurledFinishLib_v2_1.scad file must either be installed in your OpenSCAD library directory or be in the same directory as TrimmerPotentiometerKnob.scad.
A number of examples are included. To use them place the TrimmerPotentiometerKnob.json. file in the same directory as TrimmerPotentiometerKnob.scad.
If you want to use this module in your own code, note the parameters to the module in the Console log and simply include the Knob module in your code along with the "use <KnurledFinishLib_v2_1.scad>" line. None of the initialization code is needed for that application.
Parameters
To disable any part set its height to 0.
General settings
$fn → Number of segments in a circle
Knob parts are listed from lowest (closest to trimmer/potentiometer) to highest.
s_o → Stem outer (d, h)
An outer sheath surrounding and dropping below the inner stem. This is designed to act as a guide, support, and strain relief for board-mounted trimmers.
This part will not be shown if hide_s_o (Hide stem outer under Actuator) is selected.
- d → Outer diameter (inner diameter is
s_i→d) - h → Height below inner stem's lower surface; overall height of outer stem is
s_i→h + s_o→h.
s_i → Stem inner (d, h)
The lowest (non-sheath) part of the knob.
For trimmers the actuator is placed below this part's lower surface. For stemmed potentiometers the bottom of the stem hole is at this part's lower surface.
- d → Diameter
- h → Height
f → Flange (d, h)
Retaining flange meant to contact the case's inner surface.
- d → Diameter
- h → Height
tc → Through-case cylinder (d, h)
Section of stem that penetrates the case.
- d → Diameter
- h → Height
k → Knob (lower d, upper d, h)
The section of the knob that is manipulated by the user.- lower d → Diameter of lower surface (closest to trimmer/potentiometer)
- upper d → Diameter of upper surface (ignored when hatched knurling is selected)
- h → Height
Actuator
This script supports both board-mount trimmers and shafted potentiometers. The specific dimensions needed vary from device to device. Check the part's datasheet and/or physically measure the part to determine the appropriate values.
For board-mount trimmers:
Board-mounted trimmers are manipulated using a cross-shaped actuator.
For stemmed potentiometers:
a_stem → Stem size (d, h)
- d → Diameter of the shaft
- h → Distance to penetrate knob above the inner stem's lower surface
a_flat → Stem flat (inset, h)
For flattened/D-shaped shafts this defines the flat's shape.
- inset → Distance from nominal outer edge of shaft to the surface of the flat.
- h → Height of flat below the tip of the shaft
a_knurl → Stem knurling (count, h, inset)
For knurled shafts this defines the knurling's shape.- count → Number of knurls around the shaft.
- h → Height that knurling extends below the tip of the shaft
- inset → How deep the knurling extends towards the centerline of the shaft.
Knob knurling
kk_s → Knob knurling style
Note: Hatched knobs are always cylindrical.- None → Smooth sides
- Grooved → Vertical grooves
- Hatched → Cross-hatched surface
For grooved knob knurling:
Grooves are cylindrical cuts into the knob's surface.
kk_g_n → Knob grooved knurling number
Number of grooves
kk_g_d → Knob grooved knurling diameter
Diameter of each groove's cylinder
kk_g_oh → Knob grooved knurling horizontal offset
Distance to offset each cylinder from the knob's outer surface
kk_g_ov → Knob grooved knurling vertical offset
Offset of grooves' lower edge from the bottom of knob's manipulatable portion.
kk_align → Align knob knurling
Controls the orientation of the grooves with the X-axis.- Groove on axis → One groove's centerline lies on the X-axis.
- Axis between grooves → X-axis runs halfway between the two adjacent grooves.
For hatched knob knurling:
kk_h_s → Knob hatched knurling size
Size of each bump.
kk_h_d → Knob hatched knurling depth
Radial depth from knob's outer edge to deepest point of knurling
kk_h_sa → Knob hatched knurling smooth section above
Height of smooth section above the knurling (away from potentiometer). The smooth section's surface is aligned with the knurling's innermost points.
kk_h_sb → Knob hatched knurling smooth section below
Height of smooth section below the knurling (towards the potentiometer). The smooth section's surface is aligned with the knurling's innermost points.
Pointer
Optional pointer mark to add to the knob. To adjust its orientation relative to the actuator use the a_r parameter (Actuator→Rotate actuator relative to knob).
p → Pointer style
- None → No pointer is generated.
- Inset → A groove is place on the outer and/or upper face of the knob.
- Outset → A rectilinear shape is outset from the outer and/or upper face of the knob.
- Inset and Outset → Both inset and outset pointers are generated.
- Dot → An inset circular dot in placed on the knob's top surface.
p_o_d → Pointer outset dimensions ( l, w, h, v_offset )
l → Length of top marking radially inwards from knob's lower outer surface (k→lower d).w → Width of marking perpendicular to the radial direction.h → Height of side marking vertically down from knob's top surface.v_offset → Distance to vertically shift the entire marker (both top and side).
p_o_e → Pointer outset extensions ( l, h )
l → Length to marking's outer edge radially outwards from knob's lower outer surface (k→lower d).h → Height of pointer's top above knob's top surface.
p_i → Pointer inset distances ( l, h, w, d )
l → Length of top marking radially inwards from knob's lower outer surface (k→lower d).h → Height of side marking vertically down from knob's top surface.w → Width of marking perpendicular to the radial direction.d → Depth of marking relative to knob's outer surface (side and top).
p_d → Pointer dot (d, h, offset)d → Diameter of dot.h → Depth of dot below knob's top surface.offset → Offset of dot's center point from knob's top outer edge.
Version history
1.0 Initial public release
