Original oil and gas trade magazine vintage ad for N.O. NELSON MANUFACTURING COMPANY of Edwardsville, IL. Bignall Keeler Machine Works. Pictured is the No. 20 Duplex machine with a hole 23 1/2 inches in diameter through the arbor and die head, and will handle pipe and casting from 10 to 20 inches inclusive. It is said to be the largest in the Oklahoma oil fields and is located at Wewoka. Peerless, Duplex, B&K, P.D.Q.C. Unique 1928 old oilfield petroleum drilling industry equipment magazine advertisement would look sensational matted and framed.