19-inch rack cabinet

Say how many rack units you need, how deep your gear is and what it weighs, on the wall or on the floor. The Jig folds a 19-inch cabinet around that: two sides, a lid, a pan and a back plate, EIA-310 rails bolted to the sides, a door that really turns on two pins and locks behind the side's lip, cable glands, and filler panels that fit. Every part is one flat blank, laser cut and bent on a press brake; the form tells you what each wall fixing has to hold.

What it shows

• Seven sheet-metal parts (feature.sheetMetal), six of them bent: the lid and pan with the side flanges set back at the front (insetStart, insetEnd, bendRelief), the sides with one lip, the back pan, the rails with a return on their leg (tip), the door pan, and the flat filler panel. Holes in the flanges are drawn where they lie in the flat. Cut-out sketches come and go with the form (feature.when, cutouts).
• One hinged door, driven by its opening angle (feature.transform): the door, the lock and the cam turn together about the pin axis, so the form's slider opens it; at 0 the cam has turned behind the lip.
• Lefts and rights for free (feature.mirror, feature.transform): the left side and rail are mirrors of the right's; the rear rails are moved copies. A shop cuts one blank and bends it the other way.
• Tables drive the shop's numbers (table.set, choicesFrom): sheets holds thickness, V-die, radius, shortest leg, density and strength; cable_entries holds the gland counts and hole sizes.
• The form limits itself by formulas: the gear mass cannot exceed what the rails, the back plate at the wall fixings or the floor allow; the depth follows the gear depth; the number of filler panels follows the units; a door is offered only where a catalogue cam reaches behind the lip. Outputs give the loads, the cam to order and the parts to cut.
• Assertions prove the rack is a rack: hole places by EIA-310 (measured on the rail, against numbers typed from the standard), every screw lined up with both holes it passes through, a driver path to every wall fixing, the cam behind the lip. Press-brake proof by bendable and tools/bendcheck.py.

A drawing of a rack cabinet is one height and one depth. This one is yours, and it knows what the wall has to carry.

The real thing

The standard. EIA-310-D and IEC 60297-3-100 were not read (sold, not free); the numbers come from these published pages, which were read:

The panel slots are 7.1 mm wide (the round hole's size) and 10 mm long, a choice made for play sideways; 3.75 mm of metal stays beside each slot at the panel's end.

Gear and depth. The form asks for the gear's depth from its rack ears to its far end. The front rails stand 60 mm behind the side lips (room for handles and patch cords), the cable room behind the gear is at least 90 mm (a judgement), and the cabinet depth is that sum, rounded up to 5 mm. A cabinet of 600 mm (wall) or 800 mm (floor) at most.

The parts, and how the load gets to the wall. Sides of one flat sheet with a front lip (one bend), a lid and a pan with a flange down (up) outside each side, a back pan inside the sides with four flanges, front and optional rear rails of C section whose legs lie against the sides' inner faces. Everything bolts through M6 screws driven from outside, into self-clinching nuts in the part inside: so the screw heads are on the skin and a driver reaches every one. The gear hangs on the rails, the rails hand their load to the sides through three M6 screws per rail, the sides carry it to the back's side flanges (M6 in shear), and the back plate is fixed to the wall. The lid and the pan close the box.

The door is a pan with its top and bottom flanges drilled for two ISO 7379 shoulder screws (M6, shoulder 8 mm, head 13 × 5.5, hexagon socket 4; Ganter's sheet read), one in the lid and one in the pan, in the tongue that carries past the sides. Each screw is put in from inside the door with an Allen key (the head sits in the door's own pan) and held by a nut and washer on the outside of the lid and pan; a 2 mm nylon washer on the lower one carries the door. Because the door stands in front of the sides, it turns without meeting a jamb. The pin sits in from the door's face by the hole-to-bend margin (14.9 mm in 1.5 mm steel, 17.3 mm in 2 mm), and in from the door's edge only as far as the top flange's end and the lid's side bend need (13.2 and 15.1 mm). The door's face stands forward of the side's lip by the larger of the two things the swing asks, plus 1.5 mm: the rear corner at the hinge sweeping past the lip, and the outer corner coming round at the full 110 degrees. The rear edge then clears the lip by 6.9 mm in 1.5 mm steel and 9.9 mm in 2 mm sheet; the form calculates it.

It closes behind the lip. The opposite side of the door takes a quarter-turn cam lock of the common double-D cut-out, Ø22.2 mm over the arcs and 20.2 mm across the flats (Essentra L-handle cam lock, sheet read), a 45 mm steel cam, 19 × 4 mm, that reaches behind the side's lip. The sheet gives the cam's face at H = 18.5 + CH mm from the underside of the lock's bezel, which sits on the door's outer face. So the cam needs CH of at least the door face's distance in front of the lip, plus the lip's thickness, less 18.5 mm, rounded up to the catalogue's next even offset (CH from -14 to 24 mm, in 2 mm steps above 4 mm). The output gives the CH to order: 20 mm in 1.5 mm sheet, 24 mm in 2 mm sheet, the face 1.3 to 1.9 mm behind the lip. Two assertions prove it on the model: the cam's face is 18.5 mm + CH from the door's face, and it lies behind the lip's back face. The Door choice is limited by formula to where a CH of 24 mm or less reaches. That is why 2.5 mm sheet is not offered: its larger bend margins push the door out so far that it would need a CH of about 32 mm.

Sheet and bending. Press-brake data are read from 247TailorSteel's bending guidelines:

Its tables list CRS, AlMg3 EN AW 5754 H111 and AISI 304; taking CRS for DC01 is a reading made for this Jig (cold-rolled soft steel of EN 10130 type). Minimum bend radii and the K-factor rule are those of the sheet-metal-enclosure Jig, whose README lists the sources, not re-read here (R = t for DC01 up to 2.5 mm, secondary; EN 485-2 factors for 5754 via two secondary tables; Outokumpu for 304; the METU handout for K). Holes keep the larger of 2.5 t + R and the shop's shortest leg from a bend (247TailorSteel on holes over 5 mm within the leg; 2.5 t + r is AGENTS.md's rule, from Fabcon as cited in the enclosure's README, not re-read).

Fasteners. M6 screws and clinch nuts (PEM type CLS, hole 8.75 mm, centre to edge 8.6 mm, body 11.18 mm across and 4.08 mm high; values from PEM's product pages seen through search, not its bulletin; CLS for steel and aluminium, SP for stainless, pick the shank code for your thickness). Clearance holes are the medium series of ISO 273 via Optimas' table (read: M6 6.6, M8 9, M10 11 mm). The clinch nuts in the rail legs, the back's side flanges and the sides are pressed before assembly, as the assembly order says. Cage nuts for gear on the rails: square hole 9.5 mm; a distributor lists M6 cage nuts for 0.7 to 1.6 mm and 1.7 to 2.5 mm sheet; pick the one for your sheet. M8 fixings to the wall, Ø9 mm holes, large washers 8.4 × 24 × 2 mm (DIN 9021 listings).

How heavy can it be? The wall fixing. The back plate has two keyholes below (head hole 18 mm, slot 9 mm, 18 mm travel), to hang it on, and two round 9 mm holes above. A wall cabinet pivots on its lower edge. With the gear hung at its half depth and the sheet parts measured for their real mass and centre of mass, the two upper M8 fixings take the moment as a pull. They sit in plain holes, so a 24 mm washer bears on an intact plate. The lower fixings, near the pivot, take shear on their shank at the keyhole's end and almost no pull. Pull on each upper wall anchor and Shear on each of the four wall anchors are live outputs, and their labels say who must check the anchors. What limits them is not the bolt but the sheet around it: the back plate bends locally, so the form takes a plate clamped around the fixing at the nearest folded edge as its model (a simplification: stress σ = 3 F / (π t²) · (1 − r²/a²), with the washer's radius and the distance to the fold, kept to 2/3 of the sheet's proof stress). This is a judgement and the conservative part of the number: compare EN 1993-1-3's pull-through of a screw head, which for these 24 mm washers and 1.5 mm sheet is about 7.8 kN (read in a reproduction, not the standard), an order of magnitude more. The gear mass the form allows is the lowest of the rail rule of 20 kg per unit (IBM's), the fixing rule at 95 %, and a cap per sheet (on the wall 100 kg for 1.5 mm steel, 150 kg for 2 mm, 80 kg for 2 mm aluminium, 120 kg for 1.5 mm stainless; on the floor 150, 250, 150 and 200 kg, a judgement: commercial 9 and 12 U wall cabinets of 1.2 to 1.5 mm sheet are rated about 60 kg, Intellinet's data sheets, and 100 kg for Digitus's). DC01's proof stress is taken at 140 MPa, the lower end of the range in EN 10130 listings (the same for the assumed value of the table found; 5754 H111 at 80 MPa and 1.4301 at 230 MPa, EN 10088-2 listings).

The wall itself is out of the model. The anchor you choose must be rated, from its maker's data for your wall, for the pull and the shear the form shows, and someone competent should check it. A wall anchor in a hollow block is a very different number from one in concrete; the form cannot know which you have.

Assembly, in the order a driver can reach everything. On the bench, the door off:

1. Press the clinch nuts: the sides' cap nuts before the lip is bent, the rail legs' and the back's after bending.
2. Stand the sides on the pan, inside its flanges: M6 screws through the pan's flange holes into the sides' clinch nuts (driver from outside the sides). Close the lid the same way.
3. Slide the back in from behind, between the sides; screw through the sides' holes into the back flange's nuts. The back's top and bottom flanges stiffen its edges.
4. Lift the rails in through the front and screw them from outside the sides into their leg nuts.
5. Mark the wall and set the four anchors. Drive the two lower M8 screws (hex head, no washer: the 18 mm keyhole passes a 13 mm head) until they stand 4 mm proud. Lift the empty cabinet, put its keyholes over the heads and let it slide down onto the shanks. Hold its top against the wall: on the lower screws alone it would tip forward. Drive the two upper screws with their 24 × 2 mm washers through the round holes, then tighten all four. The driver reaches every fixing straight through the open front, between the rails (a clear path is asserted for all four, rear rails included).
6. Only then fit the gear, panels and door: the door last, its screws through the door's own pan into the lid and pan from inside.

The floor cabinet stands on four M10 levelling feet in the pan. Earthing the cabinet is not modelled; any metal cabinet carrying mains gear must have its parts bonded by someone competent.

Look. Blue-grey powder coat (the sheet table's colour; the aluminium and stainless rows have their natural tone), bright rails, dark gear and panels. The workshop's warm key light tints bare aluminium beige, so its colour in the table is a cool grey that renders as a neutral silver (checked at rotations 0 and 180). The material's metallic and roughness cannot follow the table (J-053).

Parameters

Outputs at the defaults (9 U, 300 mm of gear, 40 kg, on a wall, 1.5 mm steel): outside 539 × 456 mm, 485 mm from the wall to the door's face; 88.5 mm of cable room behind the gear; sheet parts 20.54 kg; pull on an upper anchor 186 N against a plate limit of 237 N, shear 148 N each; gear allowed 50 kg at this size; cam offset CH 20 mm; radius 1.65 mm, die 10 mm, allowance 3.53 mm per bend; lid blank 585 mm wide, side blank 469 mm deep, back blank 584 mm wide.

Parts list, as outputs: rails to cut (2, or 4 with rear rails, from one blank, half bent the other way), filler panels to cut, doors to cut, and blanks in all. At the defaults that is 13: lid, pan, back, two sides, four rails, a door and three panels.

Checks

Fifty assertions, measured on the model at every change of the form (those for a door, floor cabinet, panels or a shut door that are not in play are off):

• EIA-310: three square holes in every unit on the rail; the holes of the lowest and the highest unit at the exact places (6.35, 22.225, 38.1 mm from the unit boundary, in numbers typed from the standard, not read from the variables); hole centres 465.1 mm apart; 450 mm clear between the rails; the sides' lips leave at least 488.6 mm, so 482.6 mm gear and its ears pass.
• Fit of what goes in: panels 482.6 mm wide, the stack n U less 0.8 mm, resting on the rails, and a screw through a panel's slot centred in the rail's square hole; the gear's ears on the rails, its far end the cable room from the back.
• Nothing overlaps, with the door at the angle shown: every part and all fixed hardware.
• The door works: on both pins at the running clearance of the shoulder, the door clear of the sides at the angle shown and at its designed distance when shut. The cam's face is the catalogue's H = 18.5 mm + CH from the door's face (door shut), and it lies behind the lip's back face, past its edge, not in it. The cam is on the side away from the hinges.
• The wall: a 30 mm driver path clear of the rails to all four fixings; two round holes above and two keyholes below, at their heights, none in a floor cabinet.
• Every screw: rail, back and cap screws each centred in their two holes (a screw that lands in the wrong place fails one of these), the holes in the part inside being the 8.75 mm clinch-nut holes.
• Sheet metal: bend radius at least the material's, every flange at least the shop's shortest leg, holes the margin from a bend, bend ends relieved, and the lid, pan, side and rail proven bendable with a straight punch.
• Closed forms: the lid's, side's, rail's, back's and door's blanks against the sums of flats and bend allowances; the side's volume against its flat area (holes taken out) and the bend's own correction, independent of the K-factor.
• Loads: the wall pull with the measured sheet masses within the plate limit; vent, gland and hole counts.

tools/bendcheck.py (press.json) proves each part bendable with a straight punch and the table's V-die, tools as long as the part's longest bend, 0.5 mm clear over the whole stroke: lid and pan their two flanges in either order; the side's one lip; the rail's return first, then the leg; the back and the door one opposite pair of flanges first, then the other pair (the search picks the pair). tools/jigs.py check runs it at every point of its sample (press.json lists the parts): 31 of 31 points pass, every part proven wherever it is on. The in-model assertion covers the lid, pan, side and rail at every change of the form; on the back and the door, each search measures thousands of distances, seconds of CPU at every change of a parameter, so those two are left to bendcheck (this is the regeneration cost of F-019 in the examples' feedback).

Range check: tools/jigs.py check runs check-range (111 points, seed 1): every one passes, none unproven. A wider scan by hand ran the door through nine angles from 0 to 110 degrees, on every sheet, at three cabinet sizes and both hinge sides (216 points), and 70 random combinations of the other parameters; every gear mass was also tried at its maximum at the corners of the wall range (20 points). Nothing failed. The range check and scans cover those points, not every combination.

Would they notice? A scratch copy was broken twenty-two ways and every break was caught. The K-factor of the side and the cam's offset were caught only after the checks for them were added. The breaks: the cam's face a sheet thickness out, the cam's offset 2 mm short, the lock on the hinge side, the door's swing allowance too small, the keyholes moved to the top, the hole centres 1 mm off, the unit height, the first hole, the lip narrowed so the ears could not pass, the opening reduced, the door's pin hole moved, the cam short of the lip or in front of it, a nut hole off, a rail bolt moved, a wall fixing where the rails block it, a panel slot off by 2 mm, the door gap too small to swing, the K-factor of the side, the square holes grown, the rear room reduced so the gear hits the back, a rail leg or a back flange too short for its nut hole.

Not proven: strength of the anchors in your wall, the screws in tension and shear beyond the bearing of the sheet, door sag, ventilation sized to a heat load, or the electrical safety of what you put inside.

Export

• Flat patterns, nothing to pick. In the window: File › Export, Flat patterns of every part, DXF or SVG; or Flat pattern of … for one part. Headless: file.export with "sheetMetal": ["Lid", "Pan", "Side right", "Back", "Rail right", "Door", "Panel"]. Cut: Lid and Pan (Pan has the foot holes when the cabinet stands on the floor), two sides from one blank bent the other way, four rails from one blank when the rear rails are on, one back, one door, one panel per filler. Bend data: sheetMetal.bends per part.
• For the press-brake operator: sheetMetal.bends; the outputs give radius, die and allowance; press nuts before or after bending as the assembly says.
• What to cut, how many: the parts-list outputs. cut.list is not offered as the parts list: it sees the mirrored and moved copies (left side, rails) as one-off bodies and lists the hidden helpers, so the counts come from the outputs.

The README in the model's repository has the rest (Files, Rebuild, Difficulty, Platform notes, Licence): the whole README on GitHub.