19-inch rack rail holes (EIA-310: 15.875 / 15.875 / 12.7 mm pitch, 465.1 mm spacing, 9.5 mm square) and M5 / M6 / 10-32 / 12-24 cage nuts + 2U square-hole rail gauge — dimension sheet Source: Xem Studio, https://xemstudio.com/objects/rack-cage-nuts-and-rail-holes/ (sheet CC BY 4.0) Basis: EIA-310 hole pattern as printed by Digital Loggers, Schneider Electric and Rack Solutions; cage nut sizes from RS PRO, Essentra, StarTech, Rapid Electronics (R-TECH), Hammond, HDBOLT and nVent Hoffman; one 2U rail gauge file Catalog version: 2026-10-20 Overall (mm): length 88.9, width 25.0, height 2.0 - Rail data: the vertical hole pitch repeats 5/8, 5/8, 1/2 in (15.875, 15.875, 12.7 mm) with a U of 44.45 mm starting in the middle of the 1/2 in gap; the hole columns of the two rails are 465.1 mm apart (18 5/16 in); equipment clears 450 mm between rails. These are the figures three makers print as EIA-310 (Schneider cites EIA/ECA-310-E). None of the three pages gives the hole sizes, the rail flange width or the thickness, and the standard itself was not read, so the 9.5 mm square hole comes from the cage nut sheets. - Square hole: 9.5 mm (RS PRO's description, HDBOLT 'most common'), 9.53 mm (RS PRO's attribute table) and 0.375 in = 9.54 mm (Hammond). Those are the same 3/8 in rounded; the file uses 9.525 mm. Round-hole and tapped-hole rails (for 10-32, 12-24 and M6 screws) also exist; no source read gives their hole sizes, so they are not on this page. - Cage nut body sizes are what each seller prints and they are not a standard: Essentra M5 12.5 × 9.0 mm and M6 12.5 × 9.3 mm (overall length × height), M8 16.3 × 11.6 mm; StarTech M5 about 13 × 13 × 9 mm; RS PRO M6 15 mm overall width; RS PRO prints panel thickness 0.8 – 6 mm, Rapid's R-TECH parts print panel ranges 0.7 – 1.6 and 1.7 – 2.5 mm. Rapid's sheet lists eight dimension values (A to H) without a mapping and they are shown as printed. The cage nuts snap into the square hole from the rail face. Hammond's datasheet calls out 10-32, 12-24 and M6 cage nuts for 0.375 in (9.54 mm) holes and gives torque figures that conflict between versions, so none is shown. - File: a 2U strip of rail face, 25 mm wide, 2 mm thick, with six 9.525 mm square holes on the 15.875 / 15.875 / 12.7 mm pitch, U boundaries in the middle of the 12.7 mm gaps. Width and thickness are Xem's choices. It is a hole gauge for a cage nut or square-hole cutout, not a model of a rail. Rack ears and unit heights: rack-19in-ears. Cage nuts have a clip and a captive threaded plate; no model is drawn because the clip geometry is not published as numbers. part item thread dimension / value source / note rail rack unit (U) height — 44.45 mm (1.75 in) Schneider; Rack Solutions; Digital Loggers (1.75 in) rail vertical hole pitch within a U — 5/8, 5/8, 1/2 in = 15.875, 15.875, 12.7 mm (Schneider prints 15.9, 15.9, 12.7) Digital Loggers prints 1/2, 5/8, 5/8 in repeating; Schneider 5/8, 5/8, 1/2 rail where a U starts — at the middle of the 1/2 in (12.7 mm) gap between holes; a 1U device covers three holes with the notched hole in the middle Rack Solutions; Schneider rail horizontal hole spacing (between the two rails' hole columns) — 18 5/16 in = 465.1 mm (18.312 in); Schneider ±1.6 mm Digital Loggers; Rack Solutions; Schneider rail clearance between rails (minimum) / outside edges of rails (minimum) — 450 mm (17.72 in) / 483.4 mm Digital Loggers; Schneider rail equipment front panel width — 19 in (482.6 mm) Digital Loggers; Rack Solutions (19 in) rail square hole size — 9.5 mm (RS description, HDBOLT) / 9.53 mm (RS attribute) / 0.375 in = 9.54 mm (Hammond) all three are 3/8 in rounded three ways; 9.525 mm is used for the file rail round hole, tapped hole, rail flange width and thickness — no published value found in the pages read — cage nut M6, RS PRO M6 overall width 15 mm; cutout 9.53 × 9.53 mm; for panel 0.8 – 6 mm RS PRO cage nut M5 and M6 steel, Essentra M5 / M6 overall length 12.5 mm; height 9.0 mm (M5) and 9.3 mm (M6) Essentra (item codes 34002400 and 34002401) cage nut M8 steel, Essentra M8 overall length 16.3 mm; height 11.6 mm Essentra (item 34002402) cage nut M5, StarTech CABCAGENUTS M5 length 0.5 in, width 0.5 in, height 0.4 in (1.3 × 1.3 × 0.9 cm) StarTech (product dimensions, rounded) cage nut M5 and M6, R-TECH 33-7135 to 33-7138 M5 / M6 eight values as printed, letters A to H not mapped on the sheet read: 13.72, 14.22, 6.1, 9.53, 9.53, 0.8°, and panel 0.7 – 1.6 or 1.7 – 2.5 mm Rapid Electronics (the 33-7137 panel range prints '0.7.16', read as 0.7 – 1.6) cage nut 10-32, 12-24, M6 (CAGNUT series) 10-32 / 12-24 / M6 for 0.375 in (9.54 mm) square holes; M6 sold rear-loading (CAGNUTM6) and front-loading (1421CNBF); no body dimensions on the datasheet Hammond cage nut M5, PM5CN M5 snaps into square-hole rack angles; no dimensions on the page nVent Hoffman cage nut common thread sizes M5, M6, 10-32, 12-24 10-32 UNF and 12-24 UNC are the inch pair; M5 and M6 are metric HDBOLT; Hammond Files elsewhere (not hosted by Xem Studio; license as stated by the publisher): - Digital Loggers: Rack specifications: 1.75 in U, hole spacing 1/2 - 5/8 - 5/8 in, hole columns 18 5/16 in (465.1 mm) apart, minimum opening 17.72 in (450 mm), 19 in front panel — web — Maker page; numbers only. No hole sizes — https://digital-loggers.com/rackspecs.html - Schneider Electric (FAQ FA158600): EIA/ECA-310-E as summarised: U = 1.75 in / 44.45 mm; vertical hole spacing 5/8, 5/8, 1/2 in (15.9, 15.9, 12.7 mm); horizontal 18.3 in (465 mm) ±1.6 mm; clearance 450 mm; outside edges 483.4 mm; notched hole marks the U centre — web — Maker FAQ; numbers only. No hole sizes — https://www.se.com/ie/en/faqs/FA158600 - Rack Solutions: What is EIA-310: U 1.75 in, hole pattern 1/2, 5/8, 5/8 in repeating, the U starts and stops at the middle of the 1/2 in spacing, hole columns 18 5/16 in (465.1 mm), panel width 19 in — web — Maker help page; numbers only. No hole sizes — https://help.racksolutions.com/hc/en-us/articles/10431608060692-What-is-EIA-310 - RS PRO (RS Components): Cage nut M6: overall width 15 mm, cutout 9.53 × 9.53 mm (description 9.5 × 9.5 mm), panel thickness 0.8 to 6 mm — web — Distributor page; numbers only — https://uk.rs-online.com/web/p/cage-nuts/2662265 - Essentra Components: Cage nuts M5, M6, M8 (steel, zinc plated): overall length and height — web — Maker catalogue page; numbers only — https://www.essentracomponents.com/en-gb/p/cage-nuts - StarTech: Cage nuts M5 (CABCAGENUTS): product length 0.5 in (1.3 cm), width 0.5 in (1.3 cm), height 0.4 in (0.9 cm); square cage nut design for racks with square holes — web — Maker datasheet; numbers only — https://pdf.bomkeyelectronics.com/pdf/31/cabcagenuts_datasheet.pdf - Rapid Electronics (R-TECH 33-7135 to 33-7138 sheet): Panel cage nuts M5 and M6, spring steel: eight dimension values A to H per part (letters not mapped on the extracted sheet), panel ranges 0.7 to 1.6 and 1.7 to 2.5 mm — web — Distributor sheet; numbers only — https://static.rapidonline.com/pdf/33-7136_v1.pdf - Hammond Manufacturing (via SIC Components datasheet): CAGNUT series: 10-32, 12-24 and M6 cage nuts for 0.375 in (9.54 mm) square-hole punched panel rails; spring steel — web — Maker datasheet; numbers only. No body dimensions — https://datasheet.sic-components.com/cagnut.pdf - HDBOLT: Cage nut: thread sizes M5, M6, 10-32 UNF, 12-24 UNC; square hole 9.5 mm (3/8 in) most common — web — Seller page; numbers only — https://hdbolt-final.pages.dev/nuts/cage-nut.html - nVent Hoffman: PM5CN cage nut package for square-hole rack angles, M5, mild steel, plated; snaps into the square holes (data sheet linked on the page was not read) — web — Maker product page; no dimensions on the page — https://hoffman.nvent.com/en/hoffman/PM5CN Free files (CC BY 4.0, Xem Studio; STEP + STL, 1 parts): https://xemstudio.com/files/hardware/rack-cage-nuts-and-rail-holes/index.json API: https://xemstudio.com/api/geometry?object=rack-cage-nuts-and-rail-holes