The Union Manufacturing Company was founded in the late spring of 1860 when 42 prominent Richmond businessmen operating under the name "Old Dominion Company" convinced John H. Lester, a Connecticut native, to move his Brooklyn plant for manufacturing planing machines, steam engines, and sewing machines to Richmond. After relocating to Richmond the entity began operating under the name of Lester Manufacturing Company. Lester would withdraw from the firm on April 1, 1861 after a controversy over the manufacture of Elliptic sewing machines and from the overvaluation of Lester's machinery that had been moved to Richmond, and sew the firm for the value of his stock. The suit would be settled in December of 1863. Slightly before Lester's withdrawal, at least February of 1861, the company voted to reorganize, and changed its name to the Union Manufacturing Company. The company had two major branches; one for the manufacturing of sewing machines and the other for arms manufacture. Apparently, the firm also expended operations to also include Woodworth's Planing Machines as well as Steam Engines.
     Although Lester would later deny at his military tribunal, during February and March of 1861 he actively pursued arms making machinery and an arms contract for 5,000 to 10,000 Enfield rifle-muskets for the Commonwealth of Virginia. A March proposal from the firm offered to lease the Virginia State Armory for 10 years and commence to altering the existing flintlock muskets at a rate of $1.50 per alteration.
     After Lester's departure the firm would effect the alteration of muskets for Virginia, although at a much higher rate. In 1861 and 1862 the firm would receive payments totaling $45,550.00 for the alteration of muskets. No record survives detailing the exact price per alteration accorded to the Union Manufacturing Company, however, the forensic accounting of John Murphy and Howard Madaus an estimate of $5.75 per alteration, which is considerably more than what other contractors are known to have been paid. The $5.75 figure would account for the alteration of roughly 7,900 muskets. However, if the firm was paid commensurate to other contractors, at $4.00 or $4.50 an alteration, a total of 11,315 or 10,060 muskets respectively is reached. Records from the Virginia Chief of Ordnance indicate that the two main contractors for the alteration of muskets were to alter 10,000 muskets each, hence, $4.50 per alteration is probably a fairly accurate figure, and the extra money constitutes payments for extra cones and perhaps cone seats.
     The Union Manufacturing Company was one of very few Confederate contractors to mark their arms. Those muskets altered by the Union Manufacturing Company bare a "U" mark struck on the inner face of the hammer, in association with an alteration number in Arabi