Truck Box Drawing Package

Type the length, height and depth of an aluminium tread plate underbody truck box on the drawing and get a seven-sheet shop drawing set, as PDF and DXF, with five cut files, drawn from a 3D model of the box.

Dimensions

The generator opens full screen and you type the sizes on the drawing. It needs JavaScript; if you are reading this, it is off or still loading.

Box length, outside (24 to 72 in)
Box height, outside (12 to 24 in)
Box depth, outside (12 to 24 in)
Title block: company, project, drawing number, designed / drawn / checked, date

Results

General arrangement: three views, isometric, parts list
Sections and details: frame, seal, latch, hinge; the door swing check
Item 1 wrap: flat, formed section, bend table
Item 2 end panels: flats, plan, bend table
Item 3 door: flat, corner and latch cut-out details, bend table
Items 4 to 9: cable tab, hinge, seal, bought parts
Assembly: exploded view, rivets and welds, sequence

The ZIP also holds the set as PDF and DXF, five cut DXFs, a manifest, the checking script and a README.

Preview

Click a blue number on the drawing to change it; the results that change light up.

Assumptions and limits

read before you cut

Read these before you cut anything. They describe exactly what this tool does and does not account for.

An underbody box of 0.125 aluminium tread plate (5052), tread outside. The frame and the door stops are bent from the wrap and the end panels. The door sits 0.25 in and is bent twice all round (return 1.00, lip 0.75) with welded corners. A continuous hinge on the sill, a sponge D-bulb seal on the stops, recessed T-handle latches (TCH 500-51111805 or equal) and two cables that hold the door at 90°.
Outside sizes: length 24 to 72 in, height and depth 12 to 24 in. One centred latch below 36 in of length, two from 36 in.
The tread lugs are taken as 0.0625 proud of the plate. Gaps between two tread faces are drawn lug to lug, and parts on a tread face (hinge leaves, latch flanges, rivet heads) sit on the lug tops. If your plate’s pattern is taller, tell us.
Flats use K = 0.445 and an inside radius of 1.5 × the sheet; make a test bend and adjust before cutting the set. Every flange is checked against a 0.80 in die.
Geometry and fabrication only: the sheet, welds, hinge and mounting are not sized for any load. Mount the box on bottom-support brackets.
Inches only: the design is drawn in inches. No DWG file: the drawing-set DXF opens in AutoCAD and other CAD programs and can be saved as DWG there.

Output is a planning and fabrication aid. You are responsible for verifying dimensions, tolerances and material behaviour before production — full disclaimer.

Worked example

The sample: 48 × 18 × 18 in. Clear opening 44.50 × 14.50, door 45.500 × 15.500 outside its returns, two latches, ten hinge rivets. Flats: wrap 47.750 × 59.305, end panels 20.896 × 18.000, door 48.028 × 18.028.

The door swing on the model: 0.090 lug to lug at the top frame at 2.25° open, 0.065 from the hinge leaf to the sill lugs, 0.125 lug to lug at the sides; the latch pawl turns 0.020 behind the stop and, latched, catches the stop as soon as the door starts to open. Aluminium parts about 58 lb at 1.90 lb/ft² for the tread. Its cut files pass all 40 checks of the script (output).

Method

The box is a solid model built in your browser: each sheet part is its bent profile with true inside radii, extruded and cut for holes, reliefs and the latch cut-outs; the latch, hinge, seal and rivets are modelled from their makers’ sizes. The views are hidden-line projections of those solids, the sections are cuts through them, and the flats come from the same profiles and are checked against the solids’ volumes.

The door swing check turns the door about the hinge axis and measures the smallest gap between every door part and every box part at each angle, with every tread face carrying its lugs. Each sheet is one list of lines, arcs, text and tables; the screen, the PDF and the DXF are written from it.

How it was built and checked: the case study. For a plain bent box or tray, the box and tray blank calculator; for the brake, the press brake tonnage calculator.

How this tool is verified

The cut files are checked by a separate Python script using ezdxf, an independent DXF library: every corner of every flat worked out again from the three sizes with the textbook bend allowance, every bend line’s place and up or down side, every line of the latch cut-outs to the maker’s template, every hole and the metal around it, nothing else on the cut layer, the weights and the cable clearance. The script is in every ZIP; a test shows it fails on a moved bend line, a stray cut line or an extra hole.
The 3D model in the browser was compared with an independent CadQuery (OpenCascade) model at 24 × 12 × 12, 48 × 18 × 18 and 72 × 24 × 24 in: sheet part volumes within 0.01 %, section areas within 0.5 %, every line of its views found in the browser’s views, and the door gaps within 0.0025 in, the browser reporting the smaller.
175 sizes from 24 × 12 × 12 to 72 × 24 × 24 were drawn in English and French with no text over a line; the tests redraw twelve of them on every change. The sample set on this page is the generator’s own output; a test fails if it differs by one byte.

The method, the reports and the responsibility boundary are on the Verification page.

Questions

What is in the download?

One ZIP: the seven-sheet drawing set as a PDF and as a DXF (the same sheets), five cut DXFs (wrap, left and right end panels, door, cable tab), a manifest with the sizes, flats, weights and the door swing check, a Python script that checks the cut files, and a README.

What do the seven sheets show?

General arrangement in three views with an isometric and the parts list; sections and details of the frame, seal, latch and hinge; the wrap, the end panels and the door, each flat with its bend table; the small and bought parts; and the exploded view with the rivet and weld schedules and the assembly sequence.

Why does sheet 2 change a few seconds after I type a size?

The door swing is checked on the 3D model of your size: the door turns from shut to 90° and the smallest gap to the box is measured at 26 angles, tread lugs included. Sheet 2 shows the result when it is done; the download waits for it.

Are my sizes sent anywhere?

No. The model, the drawing and the ZIP are made in your browser. The site counts that a drawing was made or downloaded; never the sizes or the title block. The sizes are sent only if you send a “Found a mistake?” report and tick the box to attach them.

Why does it refuse some sizes?

Sizes outside the range above. It would also refuse a box whose door touched the frame as it swings, whose latch pawl would not catch behind the stop, or whose cables rubbed on the stops. We ran the swing check on every height from 12 to 24 in at lengths 24 and 48 and depths 12 and 24: none did.

Missing an option?

A different datum, an offset, a shop allowance, another shape altogether — say what this tool does not cover yet. Requests decide what gets built next, and a report of a wrong result is dealt with before anything new.

Request an option

Rather have the whole job done — drawings, cut files, the shop documentation, mistakes caught before cutting? Quoted per job: how we help shops.