1U Rack Tray: Ears Folded Off the Walls

Q: Which edge do you pick for an ear?

The front end of the side wall. The ear folds off the wall's front end, the short vertical edge, so it stands in the rack's front plane.

Q: The tray is {{W}} wide. Why is the ear's height more than half of 482.6 − {{W}}?

It's measured from the wall's inside face, so add the sheet's thickness. An ear on a wall's end is measured from the wall's inside face, which is one sheet thickness inside the tray's outline. Add 1.2 mm and the ears end at exactly 482.6.

Q: Why are the walls 43.6 high and not 44.45?

To leave a gap to the next unit in the rack. 1U is 44.45 mm. A part made exactly 1U would touch the units above and below, so it's made a little lower.

In 7 minutes you'll fold a tray that fits a 19-inch rack: side walls one rack unit high, then an ear folded off the front end of each wall, sized so the ears come to exactly 482.6 mm, with the rack's slots cut in.

Lesson: Sheet 04 of 05
Part: Rack Ears
Rule: Steel 1.2mm
Sheet: t 1.2 · R 1.2 · K 0.42
Time: 7 min
Status: Open

Watch

Video in productionBuild along with the steps below meanwhile.

Turn the part

Drag to turn, scroll or pinch to zoom. Flat shows the blank before it is bent: the same sheet, the same frame.

Build it in SolidCraft

Your task

Build this 1U tray for a 19-inch rack from the drawing. It slides into the rack and bolts on through its ears.

The rule from the drawing's notes, then the base on XY at the origin, and Flange.
From what you know: the two side walls and the rear wall in one Flange, the rear lip folded in, the front lip.
New this time: the ears. Flange, and pick the front end of each side wall, the short vertical edge. The ears must bring the tray to 482.6 mm across: each is half of 482.6 − the tray's width, plus 1.2, because an ear on a wall's end is measured from the wall's inside face.
The rack slots: a sketch on the XZ plane, the four slots from the drawing, Extrude, Cut, Through All, both directions.
Flat Pattern: read the Flat size and the Bends.

What to write down

Box 1: The Flat size, first number.
Box 2: The Flat size, second number.
Box 3: The number of bends.

Type them below and press Check.

Check your numbers

Enter what SolidCraft shows you. Each value is checked against SolidCraft's own result, within the tolerance shown. Nothing you type leaves this page.

Box 1Flat size, first number ± 0.05 mm mm

Box 2Flat size, second number ± 0.05 mm mm

Box 3Number of bends exact

Stuck? Compare with the finished part

Download the finished part

Open it in SolidCraft (File › Open) next to yours and compare the timeline, the rule and each feature's sizes: the first one that differs is where yours went wrong.

exercise · Steel 1.2mm · t 1.2 · R 1.2 · K 0.42 · all dimensions in mm, from the blank's left and bottom edges

Flat blank 512.953 × 376.730 mm · 7 bends

Bend	Angle	Dir.	R mm	Length mm	Allowance mm
1	90°	up	1.2	295.2	2.677
2	90°	up	1.2	295.2	2.677
3	90°	up	1.2	425.2	2.677
4	90°	up	1.2	425.9	2.677
5	90°	up	1.2	425.2	2.677
6	90°	down	1.2	41.2	2.677
7	90°	down	1.2	41.2	2.677

exercise-short · Steel 1.2mm · t 1.2 · R 1.2 · K 0.42 · all dimensions in mm, from the blank's left and bottom edges

Flat blank 512.953 × 375.530 mm · 7 bends

Bend	Angle	Dir.	R mm	Length mm	Allowance mm
1	90°	up	1.2	295.2	2.677
2	90°	up	1.2	295.2	2.677
3	90°	up	1.2	425.2	2.677
4	90°	up	1.2	425.9	2.677
5	90°	up	1.2	425.2	2.677
6	90°	down	1.2	41.2	2.677
7	90°	down	1.2	41.2	2.677

Quiz

Q1Which edge do you pick for an ear?

Q2The tray is {{W}} wide. Why is the ear's height more than half of 482.6 − {{W}}?

Q3Why are the walls 43.6 high and not 44.45?