Bar grating designations: 19-W-4, 19-W-2, 15-SGI-2, 11-W-4 — bearing bar spacing, cross bar spacing, bearing bar sizes and weight per sq ft (NAAMM MBG 531 style) — dimension sheet Source: Xem Studio, https://xemstudio.com/objects/bar-grating-designations-19-w-4-naamm/ (sheet CC BY 4.0) Basis: Direct Metals' designation key and size lists, McNichols' welded grating series GW-75 to GW-250, Metals Depot's stock list and two McNichols item pages; numbers only, load tables left out on purpose Catalog version: 2026-10-20 Sizes: see table below - Designation (the NAAMM Metal Bar Grating Manual, MBG 531, system as the distributors print it): the first number is the centre-to-centre spacing of the bearing bars in sixteenths of an inch (19 = 19/16 = 1-3/16 in), the letter(s) give the method (W welded steel, SG swaged rectangular bar, SGF swaged flush top, SGI swaged I-bar, R riveted steel, AR riveted aluminum), and the last number is the cross bar spacing in inches (usually 4 or 2); for riveted grating it is the rivet spacing (7, 3-1/2 or 5 in) and the first number is the space between bars, not centre to centre. So 19-W-4 is welded steel grating with bearing bars on 1-3/16 in centres and cross bars on 4 in centres. The MBG 531 manual itself was not read (the copies found are behind a login or a document site); the key above is as Direct Metals prints it and McNichols prints 'product spacing designation: 19-W-4 (19 = 1-3/16 in bearing bar spacing, W = welded, 4 = 4 in cross bar spacing)'. - Bearing bar size is height (depth) × thickness, in inches. Standard-duty 19-W-4 steel uses bars from 3/4 × 1/8 to 2-1/2 × 3/16 in (McNichols series GW-75 to GW-250); heavy-duty welded bars run 1 × 1/4 to 6 × 1/2 in (Direct Metals; standard centres 15/16, 13/16, 1-3/8, 1-7/8 and 2-3/8 in). The clear space between bearing bars is the centre spacing minus the bar thickness (computed here): 1-3/16 − 3/16 = 1 in, which McNichols prints for GW-175. Open area also depends on the cross bars: McNichols prints 77% for 1-3/4 × 3/16 with 1/4 in twisted cross rods, a Sweets submittal sheet prints 83% for 1/8 in bars. - Weights disagree between sellers and finishes: 1 × 3/16 in 19-W-4 is 7.5 lb per sq ft at McNichols and 7.30 (black) or 7.67 (galvanized) at Metals Depot; 2 × 3/16 is 14.1 and 13.90 / 14.20; 1-1/2 × 3/16 is 10.8 and 10.60 / 11.00. The 19-W-2 column in the McNichols sheet adds 0.9 lb per sq ft over 19-W-4 for every bar size (the extra cross bars). Metals Depot lists the bar as thickness × depth (1/8 × 1) where McNichols lists height × thickness (1 × 1/8); the page shows depth × thickness for both. - Left out on purpose: span / load / deflection tables (they belong to the maker's published load tables for the exact series and finish), serrated-surface and ADA-specific details beyond the 11-W-4 stock rows, aluminum swaged and I-bar weights (the extract was garbled) and panel-width charts. No file: a grating panel's cross bar (twisted rod) and weld geometry are not published as numbers. McNichols publishes a spec sheet and CAD drawing PDF per grating item (the item page is linked, nothing is copied). Expanded steel and aluminum grating (also sold by pounds per sq ft): expanded-metal-standard-designations-swd-lwd. source designation bearing bar size (depth × thickness) bearing bar spacing clear space between bars (computed) cross bar spacing / size method / material weight (lb per sq ft) note Direct Metals key 19-W-4 — 19/16 in (1-3/16) centre to centre — 4 in centre to centre welded steel — first number = bearing bar spacing in 1/16 in (30.16 mm centre to centre) Direct Metals key 19-W-2 — 19/16 in (1-3/16) centre to centre — 2 in centre to centre welded steel — first number = bearing bar spacing in 1/16 in (30.16 mm centre to centre) Direct Metals key 15-SGI-2 — 15/16 in centre to centre — 2 in centre to centre swaged I-bar — first number = bearing bar spacing in 1/16 in (23.81 mm centre to centre) Direct Metals key 38-W-4 (or 2) — 38/16 in (2-3/8) centre to centre — 4 in (or 2) centre to centre welded steel — first number = bearing bar spacing in 1/16 in (60.32 mm centre to centre) Direct Metals key 30-W-4 (or 2) — 30/16 in (1-7/8) centre to centre — 4 in (or 2) centre to centre welded steel — first number = bearing bar spacing in 1/16 in (47.62 mm centre to centre) Direct Metals key 22-W-4 (or 2) — 22/16 in (1-3/8) centre to centre — 4 in (or 2) centre to centre welded steel — first number = bearing bar spacing in 1/16 in (34.92 mm centre to centre) Direct Metals key 11-SG-4 (or 2) — 11/16 in centre to centre — 4 in (or 2) centre to centre swaged rectangular bar — first number = bearing bar spacing in 1/16 in (17.46 mm centre to centre) Direct Metals key 7-SG-4 (or 2) — 7/16 in centre to centre — 4 in (or 2) centre to centre swaged rectangular bar — first number = bearing bar spacing in 1/16 in (11.11 mm centre to centre) Direct Metals key 18-R-7 (or 3-1/2) — 18/16 in = 1-1/8 in space between bars — 7 in (or 3-1/2) rivet spacing riveted steel — riveted grating marking is the space between bars, not centre to centre Direct Metals key 37-R-5 — 37/16 in = 2-5/16 in space between bars — 5 in rivet spacing riveted steel — riveted grating marking is the space between bars, not centre to centre Direct Metals key 12-R-7 (or 3-1/2) — 12/16 in = 3/4 in space between bars — 7 in (or 3-1/2) rivet spacing riveted steel — riveted grating marking is the space between bars, not centre to centre McNichols GW-75-A 19-W-4 3/4 × 1/8 in 1-3/16 in 1.0625 in (27.0 mm) 4 in welded steel, carbon / galvanized (load-table sheet) 4.1 bar depth × thickness; clear space = 1-3/16 − thickness (computed) McNichols GW-75-A 19-W-2 3/4 × 1/8 in 1-3/16 in 1.0625 in (27.0 mm) 2 in welded steel, carbon / galvanized (load-table sheet) 5.0 bar depth × thickness; clear space = 1-3/16 − thickness (computed) McNichols GW-75 19-W-4 3/4 × 3/16 in 1-3/16 in 1.0000 in (25.4 mm) 4 in welded steel, carbon / galvanized (load-table sheet) 5.8 bar depth × thickness; clear space = 1-3/16 − thickness (computed) McNichols GW-75 19-W-2 3/4 × 3/16 in 1-3/16 in 1.0000 in (25.4 mm) 2 in welded steel, carbon / galvanized (load-table sheet) 6.7 bar depth × thickness; clear space = 1-3/16 − thickness (computed) McNichols GW-100-A 19-W-4 1 × 1/8 in 1-3/16 in 1.0625 in (27.0 mm) 4 in welded steel, carbon / galvanized (load-table sheet) 5.2 bar depth × thickness; clear space = 1-3/16 − thickness (computed) McNichols GW-100-A 19-W-2 1 × 1/8 in 1-3/16 in 1.0625 in (27.0 mm) 2 in welded steel, carbon / galvanized (load-table sheet) 6.1 bar depth × thickness; clear space = 1-3/16 − thickness (computed) McNichols GW-100 19-W-4 1 × 3/16 in 1-3/16 in 1.0000 in (25.4 mm) 4 in welded steel, carbon / galvanized (load-table sheet) 7.5 bar depth × thickness; clear space = 1-3/16 − thickness (computed) McNichols GW-100 19-W-2 1 × 3/16 in 1-3/16 in 1.0000 in (25.4 mm) 2 in welded steel, carbon / galvanized (load-table sheet) 8.4 bar depth × thickness; clear space = 1-3/16 − thickness (computed) McNichols GW-125-A 19-W-4 1-1/4 × 1/8 in 1-3/16 in 1.0625 in (27.0 mm) 4 in welded steel, carbon / galvanized (load-table sheet) 6.3 bar depth × thickness; clear space = 1-3/16 − thickness (computed) McNichols GW-125-A 19-W-2 1-1/4 × 1/8 in 1-3/16 in 1.0625 in (27.0 mm) 2 in welded steel, carbon / galvanized (load-table sheet) 7.2 bar depth × thickness; clear space = 1-3/16 − thickness (computed) McNichols GW-125 19-W-4 1-1/4 × 3/16 in 1-3/16 in 1.0000 in (25.4 mm) 4 in welded steel, carbon / galvanized (load-table sheet) 9.1 bar depth × thickness; clear space = 1-3/16 − thickness (computed) McNichols GW-125 19-W-2 1-1/4 × 3/16 in 1-3/16 in 1.0000 in (25.4 mm) 2 in welded steel, carbon / galvanized (load-table sheet) 10.0 bar depth × thickness; clear space = 1-3/16 − thickness (computed) McNichols GW-150-A 19-W-4 1-1/2 × 1/8 in 1-3/16 in 1.0625 in (27.0 mm) 4 in welded steel, carbon / galvanized (load-table sheet) 7.4 bar depth × thickness; clear space = 1-3/16 − thickness (computed) McNichols GW-150-A 19-W-2 1-1/2 × 1/8 in 1-3/16 in 1.0625 in (27.0 mm) 2 in welded steel, carbon / galvanized (load-table sheet) 8.3 bar depth × thickness; clear space = 1-3/16 − thickness (computed) McNichols GW-150 19-W-4 1-1/2 × 3/16 in 1-3/16 in 1.0000 in (25.4 mm) 4 in welded steel, carbon / galvanized (load-table sheet) 10.8 bar depth × thickness; clear space = 1-3/16 − thickness (computed) McNichols GW-150 19-W-2 1-1/2 × 3/16 in 1-3/16 in 1.0000 in (25.4 mm) 2 in welded steel, carbon / galvanized (load-table sheet) 11.7 bar depth × thickness; clear space = 1-3/16 − thickness (computed) McNichols GW-175 19-W-4 1-3/4 × 3/16 in 1-3/16 in 1.0000 in (25.4 mm) 4 in welded steel, carbon / galvanized (load-table sheet) 12.5 bar depth × thickness; clear space = 1-3/16 − thickness (computed) McNichols GW-175 19-W-2 1-3/4 × 3/16 in 1-3/16 in 1.0000 in (25.4 mm) 2 in welded steel, carbon / galvanized (load-table sheet) 13.4 bar depth × thickness; clear space = 1-3/16 − thickness (computed) McNichols GW-200 19-W-4 2 × 3/16 in 1-3/16 in 1.0000 in (25.4 mm) 4 in welded steel, carbon / galvanized (load-table sheet) 14.1 bar depth × thickness; clear space = 1-3/16 − thickness (computed) McNichols GW-200 19-W-2 2 × 3/16 in 1-3/16 in 1.0000 in (25.4 mm) 2 in welded steel, carbon / galvanized (load-table sheet) 15.0 bar depth × thickness; clear space = 1-3/16 − thickness (computed) McNichols GW-225 19-W-4 2-1/4 × 3/16 in 1-3/16 in 1.0000 in (25.4 mm) 4 in welded steel, carbon / galvanized (load-table sheet) 15.8 bar depth × thickness; clear space = 1-3/16 − thickness (computed) McNichols GW-225 19-W-2 2-1/4 × 3/16 in 1-3/16 in 1.0000 in (25.4 mm) 2 in welded steel, carbon / galvanized (load-table sheet) 16.7 bar depth × thickness; clear space = 1-3/16 − thickness (computed) McNichols GW-250 19-W-4 2-1/2 × 3/16 in 1-3/16 in 1.0000 in (25.4 mm) 4 in welded steel, carbon / galvanized (load-table sheet) 17.4 bar depth × thickness; clear space = 1-3/16 − thickness (computed) McNichols GW-250 19-W-2 2-1/2 × 3/16 in 1-3/16 in 1.0000 in (25.4 mm) 2 in welded steel, carbon / galvanized (load-table sheet) 18.3 bar depth × thickness; clear space = 1-3/16 − thickness (computed) Metals Depot G1181 19-W-4 1 × 1/8 in 1-3/16 in 1.0625 in (27.0 mm) 4 in welded steel, black, smooth 5.1 bar listed as thickness × depth by the seller; shown here depth × thickness Metals Depot G131634 19-W-4 3/4 × 3/16 in 1-3/16 in 1.0000 in (25.4 mm) 4 in welded steel, black, smooth 5.6 bar listed as thickness × depth by the seller; shown here depth × thickness Metals Depot G13161 19-W-4 1 × 3/16 in 1-3/16 in 1.0000 in (25.4 mm) 4 in welded steel, black, smooth 7.3 bar listed as thickness × depth by the seller; shown here depth × thickness Metals Depot G13161-G 19-W-4 1 × 3/16 in 1-3/16 in 1.0000 in (25.4 mm) 4 in welded steel, galvanized, smooth 7.67 bar listed as thickness × depth by the seller; shown here depth × thickness Metals Depot G1316114 19-W-4 1-1/4 × 3/16 in 1-3/16 in 1.0000 in (25.4 mm) 4 in welded steel, black, smooth 8.9 bar listed as thickness × depth by the seller; shown here depth × thickness Metals Depot G1316114-G 19-W-4 1-1/4 × 3/16 in 1-3/16 in 1.0000 in (25.4 mm) 4 in welded steel, galvanized, smooth 9.35 bar listed as thickness × depth by the seller; shown here depth × thickness Metals Depot G1316112 19-W-4 1-1/2 × 3/16 in 1-3/16 in 1.0000 in (25.4 mm) 4 in welded steel, black, smooth 10.6 bar listed as thickness × depth by the seller; shown here depth × thickness Metals Depot G1316112-G 19-W-4 1-1/2 × 3/16 in 1-3/16 in 1.0000 in (25.4 mm) 4 in welded steel, galvanized, smooth 11.0 bar listed as thickness × depth by the seller; shown here depth × thickness Metals Depot G1316134S 19-W-4 1-3/4 × 3/16 in 1-3/16 in 1.0000 in (25.4 mm) 4 in welded steel, black, serrated 12.2 bar listed as thickness × depth by the seller; shown here depth × thickness Metals Depot G13162 19-W-4 2 × 3/16 in 1-3/16 in 1.0000 in (25.4 mm) 4 in welded steel, black, smooth 13.9 bar listed as thickness × depth by the seller; shown here depth × thickness Metals Depot G13162-G 19-W-4 2 × 3/16 in 1-3/16 in 1.0000 in (25.4 mm) 4 in welded steel, galvanized, smooth 14.2 bar listed as thickness × depth by the seller; shown here depth × thickness Metals Depot G114112 19-W-4 1-1/2 × 1/4 in 1-3/16 in 0.9375 in (23.8 mm) 4 in welded steel, black, smooth, heavy duty 13.51 bar listed as thickness × depth by the seller; shown here depth × thickness Metals Depot G1142 19-W-4 2 × 1/4 in 1-3/16 in 0.9375 in (23.8 mm) 4 in welded steel, black, smooth, heavy duty 18.7 bar listed as thickness × depth by the seller; shown here depth × thickness Metals Depot G114212 19-W-4 2-1/2 × 1/4 in 1-3/16 in 0.9375 in (23.8 mm) 4 in welded steel, black, smooth, heavy duty 23.09 bar listed as thickness × depth by the seller; shown here depth × thickness Metals Depot G1143 19-W-4 3 × 1/4 in 1-3/16 in 0.9375 in (23.8 mm) 4 in welded steel, black, smooth, heavy duty 27.5 bar listed as thickness × depth by the seller; shown here depth × thickness Metals Depot G13161-11W4-P 11-W-4 1 × 3/16 in 11/16 in 0.5000 in (12.7 mm) 4 in welded steel, black, smooth, ADA 11.9 bar listed as thickness × depth by the seller; shown here depth × thickness Metals Depot G1316114-11W4P 11-W-4 1-1/4 × 3/16 in 11/16 in 0.5000 in (12.7 mm) 4 in welded steel, black, smooth, ADA 14.7 bar listed as thickness × depth by the seller; shown here depth × thickness Metals Depot G1316112-11W4P 11-W-4 1-1/2 × 3/16 in 11/16 in 0.5000 in (12.7 mm) 4 in welded steel, black, smooth, ADA 17.5 bar listed as thickness × depth by the seller; shown here depth × thickness McNichols item 6607310122 19-W-4 (series GW-175) 1-3/4 × 3/16 in 1-3/16 in, 1 in clear 1.0000 in (25.4 mm), printed 4 in; 1/4 in square twisted rod carbon steel, hot rolled 12.50 77% open area, 10.1053 bars per foot of width (printed) Sweets submittal sheet 19-W-4 1/8 in thick — — 4 in welded — 83% open area (printed, bar 1/8 in thick) McNichols item 67153163 (SAFE-T-GRID) 19-S-4 (series TB-940-150) T-bar 1-1/2 in high, 0.940 in top flange, web 1/8 in, bottom flange 1/4 in 1-3/16 in — 4 in; 3/8 in square rod aluminum 6063-T6, swage-locked, grooved 4.30 21% open area Direct Metals stock list 19-W-4 light duty stainless 1 × 3/16, 1-1/4 × 3/16, 1-1/2 × 3/16 in 1-3/16 in — 4 in stainless 304 — stocked sizes Direct Metals stock list 7-TW-4 (TiteWeld) 3/4 to 2-1/2 in high × 3/16 in in 1/4 in steps 7/16 in — 4 in welded steel 13.73 (3/4) to 44.31 (2-1/2) 8 sizes; weights listed in order in a garbled extract, first and last only given Files elsewhere (not hosted by Xem Studio; license as stated by the publisher): - Direct Metals (grating catalogue, hosted on Simplebooklet): Glossary of bar grating: designation key (bearing bar spacing in 1/16 in, method letter, cross bar spacing) and bar grating tables: bearing bar sizes, panel widths, weights — web — Distributor catalogue; numbers only — https://simplebooklet.com/glossaryofbargrating?textonly=1 - Direct Metals (grating catalogue, hosted on Simplebooklet): Entire bar grating section: designations, bearing bar sizes by type, light and heavy duty welded steel, stainless, aluminum (the text extraction is garbled in places; only clearly legible values used) — web — Distributor catalogue; numbers only — https://simplebooklet.com/entirebargratingsection?textonly=1 - McNichols: Standard-duty welded bar grating, series GW-75 to GW-250: bearing bar height × thickness and weight in 19-W-4 and 19-W-2 (load table PDF; loads not copied) — web — Maker sheet; numbers only — https://assets.mcnichols.com/content/dam/mcnichols/resources/PDF/LT-SDW-GW-GW2-CS-GV.pdf - McNichols: Welded bar grating item 6607310122 (GW-175, 19-W-4): bearing bar 1-3/4 × 3/16, cross bar 1/4 square twisted rod, 77% open, 12.50 lb per sq ft; spec sheet and CAD drawing PDFs — PDF, DWG — Maker site terms (drawings per item; DWG may need a login) [verify license at link] — https://www.mcnichols.com/bar-grating/welded/carbon-steel-cs-66073101 - McNichols: SAFE-T-GRID aluminum swage-locked T-bar grating TB-940-150 (19-S-4): 1-1/2 in T-bar, 3/8 in square cross bar, 4.30 lb per sq ft, 21% open area — web — Maker page; numbers only — https://www.mcnichols.com/bar-grating/swage-locked/aluminum-al-67153163 - Metals Depot: Steel bar grating: stock numbers with bearing bar size, 19W4 / 11W4 spacing, 4 in cross bars, weight lb per sq ft, smooth / serrated, black / galvanized — web — Distributor page; numbers only — https://www.metalsdepot.com/steel-products/steel-bar-grating - Sweets (manufacturer submittal sheet, maker not named in the text read): Welded bar grating 19-W-4 submittal: 1/8 in bearing bar thickness, 83% open area, cross bars 4 in on centre — web — Submittal sheet; numbers only — https://sweets.construction.com/swts_content_files/1097/484577.pdf No true-size file yet: the published figures do not fix the whole shape; a measured scan is planned. API: https://xemstudio.com/api/geometry?object=bar-grating-designations-19-w-4-naamm