Standard library

KerfScript comes with libraries for the parts most laser-cut designs need: joints, hinges, dividers, hanging holes, boxes and test pieces. They are built into every KerfScript renderer: the playground, the desktop app, the command line and the JavaScript and WebAssembly libraries. A design that uses them works everywhere without extra files.

use <kerf/tabs>

part("shelf") tab_rect([200, 60], [false, true, false, true]);

use brings in a library's modules and functions. Its variables stay inside it, and a module or function of your own with the same name is used instead of the library's. Editors with the language server show each module's description when you hover over it.

Sizes are in millimetres. Joints use $thickness, the sheet thickness, so set it to what you measure. Each section has an example in the gallery that you can open in the playground.

Boxes

use <kerf/box>

Finger-jointed boxes. Example: box.kerf.

box(size, lid = false, finger)

The panels of a box as parts bottom, front, back, left, right and, with a lid, lid, placed for the assembled view.

divider(size, finger)

A divider [width, height] with finger tabs on both sides, to slide into rows of finger_holes() cut in two walls.

Tabs and slots

use <kerf/tabs>

Tab and slot joints, for one panel standing on or through another. The tabs are as deep as $thickness, so they finish flush with the far side. Example: spice-shelf.kerf, a wall shelf held together by tabs alone.

use <kerf/tabs>

// A side with a slot for the shelf 40 mm up, and the shelf
part("side") difference() {
  rect([60, 120]);
  translate([0, 40]) slots(60);
}
part("shelf") tab_rect([150, 60], [false, true, false, true]);

tabs(length, count, width, depth)

Tabs along x from 0 to length, hanging below y = 0: join them to the bottom edge of a panel.

slots(length, count, width, clearance = 0.1)

The slots that tabs() with the same length, count and width go through, centred on y = 0. clearance is added to their width and to $thickness; cut a slot gauge to find the right value for your sheet.

tab_rect(size, edges = true, count, width)

A rectangle [width, height] with tabs outside it on some edges. edges is true or false for all four, or [bottom, right, top, left].

tab_positions(length, count)

The centres of the tabs along an edge, for placing anything else that lines up with them.

Living hinges

use <kerf/hinge>

Living hinges: rows of cuts that let plywood bend. They work best in 3 mm plywood or thinner. Example: flex-box.kerf, and hinge-card.kerf for a simple fold.

use <kerf/hinge>

// A strip that bends 90° around a 10 mm radius in the middle
flex_rect([200, 60], [100], width = bend_length(10));

bend_length(r, angle = 90)

How long a living hinge must be to bend angle degrees around an inside radius r: the length of the arc through the middle of the sheet.

flex_rect(size, bends, width, spacing = 1.5, bridge = 3, r = 0)

A rectangle with a living hinge across its full height at each x in bends.

flex_box(size, r = 15, lid = true, clearance = 0.1, spacing = 1.5, bridge = 3)

A box with round corners whose four sides are one strip, part side, bent at the corners. The tabs of part bottom go through slots along the strip. Part lid rests on top, and part lid insert, glued under it, keeps it in place. size is the outside [width, depth, height], lid included, and r the outside corner radius, more than two thicknesses. The strip is bent, so the parts are not placed in an assembled view.

flex_panel(size, r, sw, sd)

The bottom of flex_box(): a rounded rectangle with tabs on its straight edges, sw long on the front and back and sd on the sides.

Dividers

use <kerf/dividers>

Dividers with slots halfway up, so a divider running one way and one running the other slide into each other. Example: drawer-organizer.kerf, a box from kerf/box with a grid of dividers inside.

use <kerf/dividers>

// Four compartments across, two front to back, in a 200 × 120 space
grid_dividers([200, 120, 40], cols = 4, rows = 2);

grid_dividers(size, cols = 2, rows = 2, clearance = 0.15, gap = 0.5, scoops = false, at = [0, 0, 0])

The dividers for a space [width, depth, height], such as the inside of a box, making cols compartments across and rows front to back. Parts long divider run left to right and cross divider front to back.

slotted_divider(length, height, at = [], from = "top", clearance = 0.15, scoops = 0)

One divider, with a slot half its height at each x in at: from the top, or from the bottom with from = "bottom". Two dividers that cross take one of each. scoops is the number of finger dips in the top edge.

Hanging

use <kerf/hanging>

Ways to hang a panel. Each module cuts its holes out of the shapes it is given; given nothing, it makes the holes themselves, for a difference() of your own. Example: wall-sign.kerf, with all three ways.

use <kerf/hanging>

// Two keyholes 120 mm apart, 12 mm below the top edge
keyholes(120, at = [80, 48]) rect([160, 60], r = 5);

keyhole(at = [0, 0], head = 9, shank = 4.5, drop = 10)

A keyhole for a screw: the head goes through the round hole, then the panel drops drop mm so the screw rests at at, at the top of the slot. head and shank are the widths of the hole and the slot: measure the screw and add a little. drop must be at least (head + shank) / 2.

keyholes(spacing, at = [0, 0], head = 9, shank = 4.5, drop = 10)

Two keyholes spacing apart, centred on at, for a panel that hangs level.

hanging_hole(at = [0, 0], d = 5, spacing = 0)

A round hole for a nail, a hook or a cord, or two spacing apart.

hanging_loop(at = [0, 0], d = 4, wall = 3)

A ring wall wide around a hole of diameter d, joined to the shapes it is given. Put it over the edge of an ornament or a tag: the hole stays open where the ring overlaps the shape. Overlap the ring with the shape, or the loop comes out as a separate piece.

Enclosures

use <kerf/enclosure>

A box whose lid comes off again, for electronics. The walls and the bottom are finger jointed. The lid overhangs the walls a little and is held by screws that go down into the walls' top edges, each into a nut that sits in a T-slot. Example: project-enclosure.kerf.

use <kerf/enclosure>

enclosure([150, 100, 60], cutouts = [
  ["front", [36, 28], 8],              // a round hole for a jack
  ["back", [72, 15], [13, 6.5]],      // a rectangle for a USB port
  ["lid", [75, 50], [70, 30], "vents"],
]);

enclosure(size, screw = 3, screw_length = 12, nut, lip, cutouts = [], finger)

Parts bottom, lid, front, back, left and right, placed for the assembled view. Two screws go into the front wall and two into the back, and one more each for every 80 mm of width.

The walls stand lip in from the edge of the lid, so a design for an [150, 100, 60] enclosure with M3 screws has walls 144 × 94 mm.

enclosure_cutouts(side, cutouts)

The holes in cutouts for one panel; enclosure() cuts them. Each is [side, [x, y], size]:

• side is "front", "back", "left", "right", "lid" or "bottom".
• [x, y] is the middle of the hole on the panel as it is drawn, from its bottom left corner. On the front and back x runs left to right as seen from the front; on the sides it runs from front to back. y runs up from the bottom of the wall.
• A number size is a round hole of that diameter, [width, height] a rectangle. Add "vents" after a rectangle to fill it with vents.

vents(size, slot = 3, pitch = 6)

Ventilation slots across [width, height], centred on the origin: upright slots slot wide with round ends, pitch apart.

Calibration

use <kerf/calibration>

Test pieces to cut once for every new material, before a design that has to fit. Their labels are text, so they need a font, as text() does; labels = false leaves them off. Example: calibration-set.kerf; the Kerf guide explains what to do with the results.

use <kerf/calibration>

$thickness = 3;
part("kerf gauge") kerf_gauge();
part("slot gauge") slot_gauge();
joint_test([0.1, 0.15, 0.2]);

kerf_gauge(strips = 10, size = [60, 25], labels = true)

A frame with strips strips inside, all separated by single cuts. Single cut lines are not moved by kerf compensation, so each takes away one kerf. Push the strips to one side and measure the gap they leave: the kerf is the gap divided by strips + 1. size is the window the strips fill.

slot_gauge(steps = 7, step = 0.1, depth = 15, labels = true)

A comb of steps slots, from narrower than $thickness to wider, step apart, each labelled with the difference. Try a scrap of the same sheet in each: the one that fits as you want is the clearance for slots() and grid_dividers().

joint_test(kerfs = [0.1, 0.15, 0.2], size = [40, 20], finger, labels = true)

A pair of finger-jointed pieces for each kerf in kerfs, parts joint <kerf> out and joint <kerf> in, each cut with that kerf compensation. The pair that holds together without glue or forcing has the kerf to set for this sheet.