Den Norske F-H Type B Lathe
Manufactured by Den Norske in Skuteviksveien, Bergan, Norway, the backgeared and screwcutting F-H Type B lathe is virtually unknown outside its native land. Using a V and flat-way bed, carriage assembly and tailstock reminiscent of the American South Bend 9-inch, it had a 130 mm (5.125") centre height and took 580 mm (22.75") between centres. Bored through a useful 26 mm (the South bend was only 19 mm), the spindle ran in parallel bore bronze bearings (50 mm at the front, 36 mm at the left) that were drawn by ring nuts into tapered sockets - the effect being to close them down and so adjust the running clearance. End thrust was amply catered for being taken by two ball races, one on the inside of the left-hand headstock wall, the other on the outer. Mounted centrally on the saddle, the cross slide appears to have a had a gib strip of the tapered type with a rather small micrometer dial and a traditional "balanced" handle. Long swarf guards were fitted to the saddle's left hand wings, these being arranged to pass in front of and behind the headstock as the carriage approached the chuck
A heavily constructed countershaft was provided with an over-centre tensioning lever the setting of which was adjusted by the usual left-and-right-hand-threaded nut. Driven by a factory-fitted 1 h.p. 1400 r.p.m. motor, eight spindle speeds were provided: four by direct drive using an "A" section V-belt running over 4-step pulleys and four in backgear. In addition (though how this was provided is not clear) a single extra speed of 1000 r.p.m was also listed as being available.
Fitted with a No. 2 Morse taper spindle, the tailstock could be set over for the turning of slight tapers - though money was saved by omitting a cam-action cross shaft and using instead a simple eye bolt locked by a self-hiding spanner.
Should any reader have a Den Norske lathe, or other machine tool, the writer would be interested to hear from you.