VB Manufacturing, Phoenix House, Tern Hill, Market Drayton, Shropshire, TF9 3PX
        TEL:                                      FAX:                                    E-Mail:
  +44 (0)1630 637375                          +44 (0)1630 637377                          sales@hegner.co.uk

speed of the motor between its extremes would be sufficient, but in practice, all motors lose the ability to develop power at the bottom and top ends of their revolution range. Gears enable any useful speed to be utilized whilst allowing the motor to keep turning within its most efficient torque generation band and, in the case of an air-cooled motor, enabling its cooling fan to maintain a stream of air over the motor casing.
     The ratios provided by the VB gearing are:
1^st        4 : 1     reduction of motor speed to final drive speed. (Range 50 ¥ 500rpm)
2 ^nd 1.25: 1     reduction of motor speed to final drive speed. (Range 150 ¥ 1350 rpm)
3 ^rd       1: 1.5  increase of final drive speed to motor speed.  (Range 250 ¥ 2600 rpm)
     This means for example that when the motor is turning at 200 rpm, in "1^st gear" the mandrel shaft will be turning four times as slowly—  that is 50rpm, etc. In  terms of everyday usage, it is totally unnecessary to go through calculations to determine the best gear to use — any more than one consciously calculates at what speed to change gear in a car. It becomes immediately  obvious that a lower gear is needed when climbing a steep hill to enable the motor to keep turning happily and

         The incorporation of a "soft"          transmission between the electric motor and the mandrel shaft additionally minimizes the work that the motor bearings have to do. They are designed to carry the load of the rotor and motor pulley — not any part of the lathe's workload. (Ask the motor manufacturers.)
         There are further advantages in the VB transmission in that the drive pulleys for every ratio are very substantially larger than those found on any outwardly similar lathe. This means that all the motor's power can be delivered through the system without  slippage and with only moderate belt tension, thereby even further

      The most inexpensive way to produce the large diameter pulleys that are a feature of the VB design is to machine them from castings. However, because gravity castings rarely have uniform density and generally only the external faces are machined, imbalance will cause vibration. VB pulleys (and the rear handwheel) are therefore machined on all faces from solid, extruded billet to ensure perfect balance.