Employers engaged in the business of general engineering or founding or jobbing or machine tool manufacturing. “General engineering, founding, jobbing” means, other than its all embracing meaning, repetitive production of metal or abrasive products by precision methods on machine tools designed or adapted to this end or the manufacture of metal castings or the performance of engineering processes or the undertaking of engineering work in connection with articles which, owing to the heavy nature thereof, cannot be handled otherwise than by use of large power driven plant or machinery.”Abrasive products” means grinding media such as grinding wheels, bricks, sticks, segments and other devices designed for the purpose of removing by mechanical abrasion metal or other surplus material from other products and in which the abrasive is composed wholly or mainly of some mineral substance embedded in a matrix of ceramic, resin, rubber, shellac or other binding material.”Machine tool manufacturing industry” means the industry in which employers and employees are associated for the manufacture of mechanical and hydraulic tools/articles and such other activities which are incidental thereto or consequent thereon.