These writ petitions have been filed by one and the same person, viz, one M/s. Sarada Industries, Ambattur Industrial Estate, Madras=58, seeking writs of certiorari quashing the orders of the Joint Secretary to the Government of India. Ministry of Finance, Department of Revenue and Insurance, the respondent in all the three petitions, made in (1) Order No. 1571 of 1974, dated 11-4 1974, confirming, on revision the order passed by the Appellate Collector of Customs, Madras, in App No. C. 3/369/173, dated 6-8-1973 (subject matter in W.P. 2632 of 1977) and (2) Order No. 3671 of 1975, dated 10-10-1975, commonly made in two revisions, confirming the orders passed by the Appellate Collector of Customs, Madras in App. No. C. 3/2256/173 (subject matter in W.P. No. 2631 of 1977) and C. 3/1911/74 (subject matter in W.P. No. 3464 of 1977).

2.The petitioner is a partnership firm carrying on the business of manufacture and sale of automobile parts, bolts, nuts and screws, at Madras. Among the various machines, installed at this factory, there is a Thread Rolling machine imported from Tsugami Corporation, Japan. The writ petitioner imported a consignment of thread roll dies and knurl