Last updated July 28, 2026
Al’s Steel Mill draws North American structural steel sections to their real profiles — tapered flanges, radiused corners and fillets included — from the dimension tables in the AISC Steel Construction Manual. You pick a shape type from a dialog, pick a size from the list, pick a view, and place it. It covers 23 shape types across W, M, S and HP beams, C and MC channels, angles, WT, ST and MT tees, pipe in three weights, square and rectangular tube, bar-size channels and formed sheet metal shapes.
This is one of the more substantial free routines on the site, and it has a pedigree: version 1.1 dates from December 1999, the copyright runs from 1998, and it was published as Tip 1779 in Cadalyst‘s tips library, where it won a fifty dollar bonus. Al Rogers wrote it, and in the header he credits the two programs it grew out of: STEEL.LSP by Jeffrey David Wells of Pellham Phillips Hagerman in Springfield, Missouri, and BEAM.LSP by Steve Q. Stapleton of Jackson, Mississippi, as modified by Bill Le Couteur.
There are metric tables in here
Worth flagging for Australian readers, because the listing does not mention it and the AISC connection suggests otherwise. Four of the twenty-two data files hold metric shapes — metric angles, channels, rounds and W-shapes. Al credits those tables to Steve Stapleton and Bill Le Couteur’s BEAM.LSP.
Set expectations properly, though: these are metric conversions of North American sections, not Australian sections. They are not the universal beams and columns from AS/NZS 3679, and they are not the RHS and SHS from AS/NZS 1163. If you need Australian sections, this is not the tool. If you are working on a North American job in metric units, it is exactly the tool.
All 22 companion files must travel together
This is the thing that will stop you if you get it wrong. STL.LSP is the program; everything it knows about steel lives in twenty-two other files that have to sit in the same directory, and that directory has to be on AutoCAD’s support file search path. There is the dialog definition (STL.DCL), a help file (STL_HELP.TXT), and twenty dimension tables with a .DIM extension — one per shape family.
Extract the whole archive into one folder and add that folder to your support path. Al’s own advice in the header is to keep custom AutoLISP in its own directory rather than mixing it into AutoCAD’s support folder, which is still good practice. Pull STL.LSP out on its own and the program will load but fail as soon as it needs a dialog or a size list.
What it does in practice
Every shape is drawn as a polyline, which is the design decision that makes the rest of it useful. Polylines can be trimmed and extended to, given a linetype, converted to a region for composite section analysis, and pushed on to 3D solids and surfaces. The routine sets the polyline width to zero before drawing and puts your original setting back afterwards.
Insertion points are chosen where a detailer would want them: top centre of a beam, top centre or centre of a tube, centre of a pipe, the heel of an angle, the heel of a channel. While it waits for you to pick the insertion point it turns on a useful set of object snaps — intersection, endpoint, midpoint, centre, node and insertion — then turns snapping off to draw the shape, then restores whatever you had. The insert prompt also takes a reference option, so you can pick a base point and then type an X and Y offset from it.
Five views are offered by radio button. The 2D end view is the default and needs nothing else; the other four want a length, and default to one unit if you do not give one. Shapes are drawn on the current layer and in the current UCS.
Command reference
The file defines a single command, STL, which opens the main dialog.
How to load it
Extract all 23 files into one directory that is on your support file search path, then load STL.LSP with APPLOAD or by typing (load "STL"). For everyday use Al suggests putting (load "STL") in your acad.lsp so it is always available, or making a toolbar button whose command is (load "STL") STL to load and start it in one go. Our AutoLISP guide covers the loading options and the search path.
Step-by-step usage
- Type STL. The main dialog opens with a button for each of the 23 shape types.
- Pick a shape type. The available sizes appear in the list box. For formed sheet metal shapes you get a pop-up to type dimensions instead.
- Pick a size. It highlights, and its dimensions are shown beside the list.
- Pick a view. 2D end view is the default; the other four need a length in the length box, defaulting to 1 unit.
- Pick OK and place the shape. Miss out a shape type or size and you get an alert asking you to try again; miss out a view and it draws the end view.
Compatibility notes
The program is dialog-driven, and DCL dialog boxes are not supported on AutoCAD LT. That makes this one full-AutoCAD only, whatever release you are on — LT 2024 brought AutoLISP to LT but not DCL. See what runs on AutoCAD LT.
The header talks about R13 and R14 menus, so this is written-for rather than tested-on as far as current releases are concerned. It alters your drawing environment while it runs — object snap mode and polyline width — and restores both. The author’s own disclaimer is blunt: the program is provided as is and with all faults, with no warranty of merchantability or fitness for a particular use. Check the dimensions it draws against your own copy of the manual before you rely on them for fabrication.
Download
| Name: | Al Rogers Steel Mill – Steel Shapes. |
| Description: | Draws North American steel shapes. |
| Type: | AutoCAD AutoLISP Routine |
| Author: | Al Rogers |
| File Size: | 39 Kb |
| Cost: | Free |
| Worked on: | AutoCAD |
| Download File: | SteelShapes.zip |
Related routines
- Wisey’s Steel Shapes — the equivalent for Australian sections.
- Structural Steel Shapes — another AISC-based shape drawer, distributed as shareware.
- Best of LISP collection — general drafting utilities to sit alongside it.