
Model E Wolf , J ahn precision miller with backgear headstock and power longitudinal feed . This machine resembles many others by similar makers of very high-quality machine tools - Mikron , Pratt & Whitney , Rivett , Waltham , Ames , etc . - being based upon a headstock adapted from a lathe . In this case the head has been arranged to slide up and down a vertical slide but is , in all other respects , similar to the simpler horizontal machines illustrated below . Model A Wolf , J ahn precision milling machine which used the headstock assembly from the Model DD lathe with a 15 mm bore ; The 350 mm x 120 mm table had a longitudinal movement of 250 mm , a cross feed of 120 mm and a vertical travel of 170 mm . Another model , the B , a power feed version of which is illustrated below , used exactly the same arrangement of headstock and compound slide , but with a backgeared version of the headstock . With its unsupported spindle the machine was only capable of stub milling and to overcome this drawback Wolf , J ahn offered the more robust and versatile G2 . Model B Wolf , J ahn precision milling machine , based on the Model A above , but with power longitudinal feed and a backgeared headstock . A high-quality vertical miller , jig-borer and jig-driller by an unknown maker - but advertised in the Melhuish catalogue of 1898 and quite possibly a Wolf-Jahn . The machine stood 22.5 inches tall , with a base 22 inches long and 11 inches wide ; The nose of the 3/4-inch diameter , tool-steel spindle stood 3.5 inches clear of the rotary table and ran in hardened double- cone bearings 1 3/16 -inches in diameter ; it was bored clear through and accepted collets tightened by a draw tube , the handwheels of which can be seen in position . The longitudinal travel of the table was 6.75 inches and the traverse movement 5.5 inches ; the machine weighed approximately 165 lbs and cost £ 30 - as much at the time as a fully specified , English-manufactured five-inch centre height Britannia No . 16 backgeared and screwcutting lathe on a treadle stand .