One of the main features of the Doughty Drive’s unique design is that there is NO backlash. It has a reduction ratio of 33.33:1,giving great holding torque of 20 ft/lbs – 27 Nm. This ratio gives a very good resolution, 66,666.666 steps per rev, and 185.185 micro steps per deg., with positional repeatability of + – 30 arc seconds.
The DD100’s have a maximum fast travel of 120 degs per second, or 20 RPM. With a chuck attached, these units can be mounted vertically or horizontally, like an indexing head or rotary table. The DD100 now incorporates slew bearings with a 28mm hole through the centre, enabling cables, hoses etc. to pass.
Doughty Drive units arranged in a A/B axis configeration. The router is a 1 HP Ryobi with a 1/2″ cutter, feed at 80″ per minute.