2020 extrusion corner bracket: parametric template

Parameters

Open in the editor opens the design with these defaults; change them afterwards in Modify › Parameters, and everything that depends on them follows. Opened from the editor’s template library instead (New ▾ › New from template…), the template asks for its values first and checks them against these ranges and against each other, and Copy link gives an address that opens it with your values.

Name	What it sets	Default	Range
`legLength`	Leg length	20 mm	15 to 60 mm, steps of 1
`width`	Width	20 mm	15 to 40 mm, steps of 1
`thickness`	Thickness	4 mm	2 to 8 mm, steps of 0.5
`holeDiameter`	Hole diameter (M5 clearance)	5.5 mm	3.4 to 6.6 mm, steps of 0.1
`gussetThickness`	Gusset thickness	2.5 mm	1.2 to 6 mm, steps of 0.1
`filletRadius`	Inside corner radius	2 mm	0.5 to 5 mm, steps of 0.25
`keyWidth`	Slot key width	5.8 mm	3 to 8 mm, steps of 0.1
`keyHeight`	Slot key height	1.5 mm	0.5 to 3 mm, steps of 0.1

Notes

Defaults suit 2020 extrusion (20 mm square, 6 mm slot) with M5 screws and T-nuts. Each leg has one hole on the slot's centre line; the keys under the legs drop into the slots and keep the bracket square, so it can be tightened without a square. For V-slot keep the key width at 5.8 mm; for 3030 or 4040 extrusion set the width to 30 or 40, the key width to 8 and the holes to 6.6 mm (M6).

The gussets stand at both sides, leaving room for the screw heads between them; they are limited automatically when the bracket is narrow. The inside corner round is kept clear of the holes, so the screw heads always sit flat.

Print the bracket lying on one of its sides (a gusset on the bed) so the layers run along both legs - it is much stronger that way than standing on a leg. PETG or ASA hold up better than PLA in a warm enclosure.