Offset Smoker Drawing Package
Type the sizes of an offset BBQ smoker on the drawing and get a nine-sheet shop drawing set, as PDF and DXF, with eleven cut files and a parts list, in millimetres or inches.
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.
- Cook chamber outside diameter
- Cook chamber shell length
- Shell and end cap thickness
- Lid front cut, above axis height
- Lid opening (arc)
- Shell left at each end of the lid
- Grate below the chamber axis
- Firebox outside width
- Firebox outside length
- Firebox outside height
- Firebox plate thickness
- Opening into the chamber, height
- Air inlet diameter
- Air inlets
- Chimney outside diameter
- Chimney wall thickness
- Chimney height above the shell
- Cart: chamber bottom above the floor
- Cart: wheel diameter
- Title block: company, project, drawing number, designed / drawn / checked, date
Results
- General arrangement: three views and an isometric
- Notes, design data, rules of thumb
- Weldment assembly: parts list, schedule of openings
- S1 shell developed
- End caps, firebox front, chimney template
- Firebox weldment and plates
- Cart weldment and cut list
- Welding details
- Isometric and assembly sequence
The ZIP also holds the set as PDF and DXF, eleven cut DXFs, a manifest, the checking script and a README.
How this tool is verified
- The cut files are checked by a separate Python script using ezdxf, an independent DXF library: the shell blank against π × the mean diameter, the lid angles and margins, every point of the chimney hole on the chimney bore, the firebox opening inside the shell with its grease bridge and its area worked out independently, the firebox plates, door, inlets and dampers, the chimney saddle, and each part's mass against the bill of material in manifest.json. The script is in every ZIP.
- Tests run that script on five smokers, from a 20 × 36 in backyard size to 40 in pipe, with the cut files in millimetres and in inches, and write all nine sheets of each to PDF and DXF.
- 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.
Built by Ruthen Systems
Free, with no account, and the dimensions you type stay in your browser (unless you choose to attach them to a mistake report). If a result looks wrong, or the option your shop needs is missing, say so — reports of a wrong result are dealt with first.
Report a problem or request a toolAssumptions and limits
Read these before you cut anything. They describe exactly what this tool does and does not account for.
- A horizontal cook chamber (new pipe, or plate rolled to a cylinder) with the lid cut out of the shell, a box firebox on one end below the grate, a chimney on top at the far end, and a square-tube cart with a firewood shelf (expanded metal) and two wheels.
- Build from new pipe or plate only. Never cut or weld a used propane, fuel, air or chemical tank: hot work on tanks that held flammables has killed people even when the tank was thought empty. No galvanized or plated steel where the fire or hot smoke reaches.
- The firebox, opening, air inlet and chimney sizes are checked against builders’ rules of thumb (Feldon’s smoker calculator). They are not engineering, builders disagree on them, and none guarantees how a smoker draws.
- The shell is developed at its mean diameter. Welds are drawn and listed but not sized; plate thickness, the cart tube and the wheels are not sized for any load. The cart is not for towing or lifting.
- Hinges, handles, gaskets and thermometers are bought and not sized here; the grates, rails and shelves are listed with their sizes. Check the local fire and open-burning bylaw.
- 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: a 609.6 mm (24 in) chamber, 1219.2 mm (48 in) long, in 6.35 mm (1/4 in) plate; a 508 mm (20 in) cube firebox; a 152.4 mm chimney 406.4 mm above the shell; 2 air inlets of Ø101.6.
Its cut files pass all 47 checks of the script (output). Against the rules of thumb: the firebox is 108% of a third of the chamber, the opening 130% and the air inlets 112% of Feldon’s figures, the chimney 113% of 5% of the firebox, and the grease bridge 165 mm against the 38 mm minimum. Steel, empty, without bought parts, grates and shelves: about 264 kg.
Method
The shell is developed at its mean diameter with the seam at the bottom; the lid is a rectangle on that blank between the two cut angles, and the chimney hole is the curve where the chimney’s bore meets the shell. The firebox opening is the firebox’s inside width by the height you set, clipped where it meets the shell. The firebox front is the firebox outline less the end cap’s circle. The chimney’s saddle comes from the same pipe-intersection engine as the pipe cut template tool.
Each sheet is one list of lines, arcs, text and tables. Three writers turn it into the picture on the screen, the PDF and the DXF, so all three are made from the same data. The sizes on the drawing are the boxes you type into.
How it was built and checked: the case study. For a single pipe saddle, the pipe cut template builder.
Questions
What is in the download?
One ZIP: the nine-sheet drawing set as a PDF and as a DXF (the same sheets), eleven cut DXFs (shell blank with the lid and chimney hole, both end caps, five firebox plates, door, damper, chimney wrap template), a manifest with the sizes and the rules-of-thumb check, a Python script that checks the cut files, and a README.
What do the nine sheets show?
General arrangement in three views with an isometric; notes, design data and the rules of thumb; the weldment assembly with item numbers, parts list and schedule of openings; the shell developed; end caps, firebox front and chimney template; the firebox weldment and its plates; the cart weldment and cut list; six sectioned weld details with a weld list; and an isometric with the assembly sequence.
Pipe or plate?
Either. From plate, cut the shell blank with the lid and chimney hole and roll it. From pipe, print the same layout at 1:1 and use it as a wrap template to mark the lid and the hole.
Are my sizes sent anywhere?
No. The drawing and the ZIP are made in your browser. The site counts that a drawing was made or downloaded, and whether in millimetres or inches; 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?
Because the parts would not fit or would not work: a firebox too wide for its opening to stay inside the shell, an opening without a 1 1/2 in grease bridge below it, inlets that do not fit on the door, a lid that runs past the top, or a cart too low for its wheels. The bar above the drawing says which, in plain words.
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.
Rather have the whole job done — drawings, cut files, the shop documentation, mistakes caught before cutting? Quoted per job: how we help shops.
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