Models for generating 2d box joints fastened with screw and nut. More...

Collaboration diagram for Box Screw:

Files
file	box_screw.scad
	Models for generating 2d box joints fastened with screw and nut.

Functions and/or Modules
module	joint2d_box_screw (conf, insts, mode=0, type=0, trim=false, align)
	Create 2d edge profiles for screw and nut box joint construction. More...

Usage Details

Models for generating 2d box joints fastened with screw and nut.

Requires:
include <omdl-base.scad>;
include <transforms/base_cs.scad>;
include <models/2d/joint/box_screw.scad>;

Function and/or Module Documentation

◆ joint2d_box_screw()

module joint2d_box_screw	(	conf	,
		insts	,
		mode	= `0`,
		type	= `0`,
		trim	= `false`,
		align
	)

Create 2d edge profiles for screw and nut box joint construction.

Parameters

conf	<datastruct> box joint length, depth, pin configuration and screw configuration (see below).
insts	<datastruct> box joint instance list (see below).
mode	<integer> global construction mode.
type	<integer> construction type {0=male additions, 1=male removals, 2=female removals}.
trim	<boolean> limit construction to within the total joint width.
align	<integer-list-2> joint alignment; edge-1, center, and edge-2 for both [x, y].

Use this module to generate a 2d profile for constructing box-joint pairs with a central screw and locking nut, as illustrated in the example below.

Set type = 0 to create the male finger profile, and set type = 2 to generate the corresponding female slot profile. To ensure proper alignment and fit, both components must be created using identical configuration parameters.

When producing interlocking joints with 3D-printed plastics, carefully control the joint clearance. Most printed plastics are relatively rigid, so insufficient gap allowance can lead to poor assembly or excessive friction.

For CNC routers and laser cutters, the interior and exterior corner radii can be adjusted to accommodate tooling limitations. This allows flat internal mating surfaces to be maintained while compensating for the minimum practical radius imposed by the cutter diameter (commonly called dogbone corner relief).

Multi-value and structured parameters

conf

e	data type	default value	parameter description
0	decimal	required	`l` : joint length
1	decimal	l/10	`d` : joint depth
2	decimal-list-5 \| decimal	d	pin default configuration
3	decimal-list-2 \| decimal	d/6	screw default configuration
4	decimal-list-4 \| decimal	d/3	nut default configuration

conf[2]: pin

e	data type	default value	parameter description
0	decimal	d	`m` : male pin width
1	decimal	m * 5/2	screw section width
2	decimal	m / 25	pin gap width
3	decimal	m / 20	pin exterior edge rounding
4	decimal	m / 20	pin interior edge rounding

conf[3]: screw

e	data type	default value	parameter description
0	decimal	d/6	`sd` : screw diameter
1	decimal	d	`sl` : screw length

conf[4]: nut

e	data type	default value	parameter description
0	decimal	d/3	nut size; flat-to-flat
1	decimal	sd	nut height
2	decimal	sl / 10	nut end offset
3	decimal	m / 20	nut interior edge rounding

insts

e	data type	default value	parameter description
0	decimal	0	zero reference; [-1, 0, +1]
1	decimal	0	length offset from reference
2	integer	7	form (see below).
3	integer		mode override (see below).
4	decimal-list-5 \| decimal		pin override (see above).
5	decimal-list-2 \| decimal		screw override (see above).
6	decimal-list-4 \| decimal		nut override (see above).

insts[2]: form

Integer value is binary encoded.

b	description
0	construct left pin at negative side of instance
1	construct right pin at positive side of instance
2	construct screw and nut section of instance

mode

Integer value is binary encoded.

b	description
0	female removal; interior vs exterior rounding
1	female removal; interior corner over cut placement
2	male removal; screw bore vs skip screw bore
3	male removal; screw nut vs skip screw nut
4	male removal; add screw bore drill punch mark

Box screw joint profile example script

    include <omdl-base.scad>;
    include <transforms/base_cs.scad>;
    include <models/2d/joint/box_screw.scad>;
 
    w = [50, 3];
 
    conf =
    [
      w.x,
      w.y,
      [3, 6, 1/8, 1/3, 1/3],
      [1/2, w.y, 1, 1/2]
    ];
 
    insts =
    [
      [-1, +3,   2+4],
      [+0, +0, 1+2+4, 1+4+16],
      [+1, -3, 1  +4],
    ];
 
    mode = 1 + 2;
 
    translate([0,-w.y])
    {
      joint2d_box_screw(conf=conf, insts=insts, mode=mode, type=0);
      difference()
      {
        translate([0, -w.y*3/4]) square([w.x, w.y * 3/2], center=true);
        joint2d_box_screw(conf=conf, insts=insts, mode=mode, type=1);
      }
    }
 
    translate([0,w.y/2])
    difference()
    {
      translate([0, w.y/2]) square([w.x, w.y*3/2], center=true);
      joint2d_box_screw(conf=conf, insts=insts, mode=mode, type=2);
    }
 
    // end_include

Box screw joint profile example diagram
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Definition at line 432 of file box_screw.scad.

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Files

Functions and/or Modules