Because the 9-inch lathes had been flat-belt driven the maker, following usual practice to optimise grip, had set the pulleys as far apart as reasonably possible. However, even after a change to V-belts (and through two changes of countershaft)  Boxford made no effort to take advantage of the shorter centres on which these can run to make the machines more compact. Early lathes, until machine No. 4600 in 1954, used an "integral" countershaft unit of unusual and ingenious design where the pulley system and motor were both mounted on a platform that could be adjusted forwards and backwards on two bars fastened to the back of headstock-end bed foot. The movement was activated a quick-action, two-start thread controlled by a handle on the end of a shaft that protruded through the front face of the bed foot immediately below the headstock. When moving these lathes, take care to support the rear of the countershaft otherwise the bars on which it sits may be bent. On later rear-drive models a very heavily built, separate 16-speed countershaft of different design was fitted with the motor mounted on a rather over-engineered (even unnecessary) horizontal platform. This allowed a separate adjustment to be easily made to the motor-countershaft belt tension. At some point the new countershaft was modified and its right-hand bearing made detachable to ease belt replacement - though it was still necessary to completely dismantle the headstock if a standard V-belt was to be used.
One problem sometimes encountered with both underdrive and rear-drive versions is vibration at high speeds and/or a knocking at lower; this can nearly always be traced to either the large countershaft pulley being out of balance or either (or both) the drive belts being unevenly worn. Well-used belts (or belts with stiff sections, caused by being left under tension for some considerable time) fall into and then ride up the pulleys, effectively varying the drive ratio, causing the speed to rise and fall rapidly and so induce vibration. Should you suffer this problem it's worth replacing both belts (the "T-link" belt on the headstock drive saves dismantling and can also, with advantage, replace the standard V-belts on the other parts of the drive). New, high-quality machine-tool specification belts (which we can supply, just email for details) can make a significant improvement to the smooth running of any machine tool. and then, if that does not affect a cure, removing the countershaft pulleys and shaft and statically balancing them between a pair of lathe centres.
An important point when dismantling Boxford drive systems: the makers were inclined to use two grub screws to lock pulleys to their shafts--the upper screw acting as a lock. So, before getting out the 14 lb hammer, do check first why it won't come apart...
A serious problem with the rear-drive machines, when used in educational establishments, was the difficulty of securing the belt guards against curious fingers. Most schools resorted to bolt-on straps and similar Heath-Robinson approaches and, as a consequence, in 1959, Boxford introduced the "Under-drive" models, a design very similar to the competing Viceroy and as already offered for many years on the American market by South Bend, Clausing, Sheldon and other mankers. With the drive now held securely in the stand behind an electrically interlocked door another advantage emerged: the depth of the machine was reduced to as little as 17-inches (400 mm).
Early under-drive lathes had their countershaft-spindle bushes pressed directly into the material of the motor platform itself, with the belt-tensioning handle mounted externally on the left-hand side of the cabinet. With the handle so temptingly placed many owners were inclined to use it as an unofficial (and dangerous) substitute for a clutch. In 1960 the countershaft was modified: the shaft diameter was increased to 0.75" and, in 1966, further improved when the shaft was increased to 1-inch diameter, the bearings fitted to removable brackets, the belt-tensioning lever repositioned within the cabinet base and the access door (like the educational versions) provided with a micro-switch that stopped the motor should it be opened by even a fraction of an inch.
While rear-drive lathes had 6, 8 or 16 spindle speeds all the under-drive machines, with the exception of the variable-speed VSL, were limited to 10.  With some variations, because of special orders or educational and training use, the usual range on the back-drive type was 30 to 1250 rpm while the Mk. 1 and Mk. 2 Underdrive types of all models (CUD, BUD and AUD) generally ran at 40, 66, 105, 165 and 270 r.p.m. in backgear and 210, 340, 540, 850 and 1400 r.p.m in open belt drive. However, on the latter machines (at extra cost) the factory could provide a more powerful motor and a  "high-speed" pulley set that increased the maximum to just over 2000 r.p.m. - but at the sacrifice of increasing the bottom speed to such an extent that it was difficult for beginners to cut threads.
It's well known that a lathe fitted with a spindle clutch is a good deal easier to handle than one without - and it remains a mystery why the only Boxford ever so fitted (as an option) was the ME10. Its design was similar to that used on the Myford ML7 with a brake-drum housing formed inside the countershaft drive pulley and an operating lever working through a push rod and toggle-arm that opened and closed a pair of brake shoes. Owners of clutch-equipped lathes report that the unit is not only reliable but has a pleasingly light yet positive action..