Ordnance Factory, Dehradun popularly known as OF Dun was conceived in 1941, as a result of the decision to shift the Mathematical Instruments Office, from 15 Wood Street, Kolkata. The aim was to establish a factory that specialized in the production of military optical instruments. OF Dun was formally established during 1943.
The factory manufactures sights and optical instruments such as the Artillery Day Light sights, Director Fire Control No 7 used with the 105 mm Light Field Gun and 155 mm 45 calibre gun system, ‘Dhanush’, Collimator Infinity Aiming Reference 102A, used in conjunction with Sight Dial 104A for collimation purpose, Sight dial 104A with mount is used with 105/37LFG and Dhanush Tripod fire control, used with Director Fire Control No 7. It also manufactures Infantry Day Light sights including Day Light telescope for 84 mm Mark-III, Day Light telescope for 5.56 mm INSAS rifle, Day Light telescope for 5.56 mm, sight for 51 mm mortar, sight unit cased 102B used with 7.62 mm Machine gun and 81 mm mortar for direct and indirect firing. Infantry passive night sights for the 5.56 mm INSAS rifle, and for the 84 mm.
It also manufactures Armoured Vehicle Sights For T-90, T-72 and BMP-II including Periscopic Observation Device 65A, Periscopic Observation Device 165A, Commander’s Periscopic Observation Device, Driver’s Periscopic Observation Device, Safety glass with heating plate Se -15, Muzzle Bore sight for 125 mm gun, Naval 12.7 mm Air Defence gun (Prahari) sights, Passive Night Sights for 12.7 mm AD gun, Day Light Telescope for 12.7 mm Air Defence gun, Surveillance sights, Bino 8×30, passive night vision goggle, passive night vision binocular (PNVB) and passive night vision monocular. MBT Arjun MK-I Sights: Driver’s Day Periscope (side), Driver’s Day Episcope (central), Commander’s Day Episcope, Gunner’s unity window, and gunner’s articulated sight
Manufacturing of such a varied range of modern optical instruments, requires state of the art modern equipment. These have been installed at OF Dun. They include CNC Fine Grinding Machines for curve generation of lenses; Grinding and Fine Grinding of optics; CNC Grinding Machines for Angular Milling of prisms; High Speed Lapping and Bevelling; CNC Machines for High Speed Polishing of Optics; CNC Laser Centring and Edging Machines; Laser Centring and Cementing Station for Chemical Silvering of Prisms and Mirrors; High Vacuum Coating Plant for Ion Assisted Deposition (IAD) of Optical Interferometric Coatings like Anti-reflection Coatings, Reflective Coatings, Metallic, Dielectric, High Resolution Photo Lithography for Precision Graticules, Glass Etching and Chrome Etching. Over period OF Dehradun has become a Centre of Excellence for Optical Instrument manufacturing in India.
