Steel Shop Drawings for Fabrication

Steel shop drawings are the fabricator's instructions for making each piece of structural and miscellaneous steel: sizes, lengths, holes, copes, welds, grades and finish, with a bill of material for the pieces shown. Fitters, welders, saw and drill line operators, shop QC and purchasing work from them, and the design team reviews them for approval.

AISC 303, the Code of Standard Practice for Steel Buildings and Bridges, places responsibility for shop and erection drawings with the fabricator and covers their review and approval by the owner's designated representative for design. Vertex prepares the drawings for your firm; the submittal travels through your contract chain to the EOR or architect.

Every sheet is extracted from an SDS/2 model, and SDS/2 is the only detailing platform the team runs. The same model produces member details, submaterial details, erection views, bolt lists, bills of material and DSTV (NC1) files, so drawings, reports and NC data can be regenerated from one model revision. The SDS/2 detailing and 3D modeling service covers the model itself. For a sheet-by-sheet walk-through of a complete package, read steel shop drawings explained.

An assembly detail, also called a member detail, shows one shipping piece: a main member with every plate, clip and stiffener shop-welded or shop-bolted to it, identified by a ship mark. A part detail shows one minor mark, such as a gusset or cap plate, with the cuts and holes needed to make it before fit-up.

The two kinds of mark tie the package together:

• Ship marks head the assembly detail, appear at the member's location on the erection drawings, and are marked on the finished piece in the shop.
• Minor marks appear on the part detail, as call-outs on every assembly that uses the part, and as lines under each ship mark in the bill of material. Identical parts share one minor mark and one part detail.
• NC files are exported per part from the same model revision, so the file loaded on the beam line or plate processor carries the mark the fitter reads on the drawing.

A fabrication-ready detail answers the questions a fitter would otherwise walk to the office to ask: overall length and dimensions to work points and member ends, hole sizes and bolt call-outs, weld symbols, the material grade of each part, and finish requirements. If a dimension has to be scaled or calculated on the shop floor, the detail is not finished.

Dimensions

Dimensions run to work points, member ends and hole groups, with gage and pitch for each hole pattern and cope, cut and bevel geometry in feet, inches and fractions. Camber appears on the member detail when the design drawings call for it.

Holes and bolts

Hole sizes follow AISC 360 Table J3.3 unless the design calls for oversized or slotted holes; the standard hole for a 3/4" bolt is 13/16". Bolt call-outs give diameter, ASTM F3125 grade and thread condition, such as A325N (threads permitted in the shear plane). The airport terminal thermal break framing project used A325N snug-tightened bolts in 13/16" holes, including (4) 3/4" dia. bolts with washers and bushings at each frame-to-structure thermal break connection.

Welds

Weld symbols follow AWS A2.4, showing arrow side or other side, size, length and pitch, and all-around welds where required. Weld sizes come from the EOR's design, and welding requirements from the specification and AWS D1.1; the reference project specified E70XX electrodes.

Grades and finish

Each part carries its ASTM grade. The reference project used A992 W shapes, A36 plate and angle, A500 Grade B tube and A53 pipe. Surface preparation and coating follow the specification, which on that project meant SSPC-SP2 cleaning and shop primer at 1.5 mils DFT. No-paint areas, such as slip-critical faying surfaces, are noted so the paint line knows what to mask.

The bill of material is generated from the same SDS/2 model as the details, so each ship mark lists its minor marks with quantity, shape and size, length, grade and unit weight. Bolts installed at the site go on a separate field bolt list instead of being mixed into shop material.

Purchasing, the saw schedule, the paint line and shipping all read those lines, so a wrong quantity or grade travels a long way. On the reference project, the frame detail sheets carried a bill of material with unit weights for each frame assembly, and the package included field bolt lists.

Material takeoffs, bolt lists and NC files are regenerated from the same model revision as the drawings they accompany, so a revised connection changes the detail, the bill of material and the NC file together.

Yes. Your shop standards are collected at intake, before modeling starts: sheet templates, piece-mark conventions, connection preferences, bolt and weld preferences, and the NC file format your equipment reads. The drawings are set up to match, so a Vertex package reads like the drawings your shop already works from.

Sheet size follows content. On the reference project, framing plans went on ARCH D (24x36) sheets and frame detail sheets used ANSI B (11x17) and ARCH C (18x24). If your standards are not written down, the open-questions list produced at intake asks for the decisions the shop needs to make, such as mark prefixes and preferred sheet sizes, before any sheets are drawn.

Drawings are issued for approval, the reviewer's comments are incorporated and clouded, and the revised set is issued for fabrication. On the reference project, Rev A was issued for approval on September 3, 2026 and Rev 0 was issued for fabrication and field use on September 9, 2026, six days later.

1. Issue for approval. Detailing proceeds on confirmed information. Open items are held or flagged on the sheets, and Vertex drafts RFIs for you to submit to the EOR or architect.
2. Incorporate comments. Each approval comment is made in the model, clouded on the affected sheets, and re-checked, and the revision advances.
3. Issue for fabrication. Drawings, bolt lists, bills of material and NC files are regenerated from the same model revision.
4. Revise after release. Later changes are clouded, recorded in the revision log, and only the affected sheets and NC files are re-issued.

The time difference shapes this loop. India Standard Time is 9 hours 30 minutes ahead of US Eastern Daylight Time, so approval comments sent at 5:00 p.m. EDT arrive at 2:30 a.m. IST the next day. The team's working day falls during your night, and a markup set sized to a working day can be back for review the next morning; larger comment sets take several cycles. The trade-off is limited same-hour answers during your afternoon. Revision volume is also one of the factors that moves a project within the published steel detailing rates.

Every drawing is checked by a second person who did not draw it, against the design drawings, specifications, RFI responses and your shop standards. The detailer makes the corrections, and the checker back-checks them before the sheet is released. Before any drawings are extracted, the model is clash-reviewed in SDS/2 and compared with the design drawings.

On a shop drawing, that comparison covers hole locations and gages at connections to other members, lengths and work-point dimensions, weld symbols against the EOR's connection requirements, minor mark quantities and grades against the bill of material, and finish notes against the specification. The full sequence, including model review and revision control, is laid out on the quality control and drawing checks page.

Shop drawings tell the fabricator how to make each piece; erection drawings tell the field crew where each piece goes and how it connects. Both come from the same SDS/2 model and share ship marks, which is how a piece built from an assembly detail finds its place on an erection plan at the site.

Both sets are part of full structural steel detailing scope. See erection drawings for steel field crews for what the field set contains.