All control levers are shown on the illustration on the opposite page. Eiecukai Controls. A single panel, on the front of the lathe, contains all the electrical controls within easy reach of the operator. A Dush-button onerated starter with overload and no-volt protection is ~tandard equip'ment on all machines; other controls available being two speed, reversing and coolant pump rotary type switches. Engagement of the leads crew for screw cutting is by means of the lever at the right of the apron wpich is pulled up for engagement and pushed down for disengagement. Simultaneous engagement of leads crew and feed rod is prevented by interlocking control. (b) HeadstocK.
Speed changes should only be made when the spindle is stopped. The standard machine incorporates a start/stop mechanical clutch and brake operated via a third shaft by control levers adjacent to gearbox and apron. An alternative electrical control by similar levers and third shaft provides direct reverse to the spindle in addition to forward and stop. The carriage may be locked to the bed by means of the hexagon screw on the right-hand side of the carriage. Exact repeat of leadscrew engagement is obtained with the screw- cutting indicator. On English models: To cut even threads per inch, engage at any graduation. To cut odd tf-....reads per inch, engage at any numbered graduation.
To cut haifrhreads per inch, engage at graduations I or 3. To cut quarte: threads per inch, engage at graduation I- On Metric models: To cut ·5, ·75, I, l"5, 2, 3 and 6 mm. P. engage at any graduation. To cut r·25, 2"5, 5 and 10 mm. P. engage at any numbered graduation. To cut 4 mm. P. engage at graduations 60 or 120.
A tV\'o-position front gear lever selects the high speed range when in the right-hand position and the low speed range in the left-hand position and this, used in conjunction with the two position twin selectors at the top of the headstock, gives a total of eight spindle speeds" Freely siiding gears combined "Nith a direct reading speed chart ensures effortless and instantaneous speed change. Forward or reverse rotation of the feed gear train is obtained by a selector lever at the front of the headstock. (c) Norton Feed Gear box. Thirty-six changes of threads and feeds are obtained by manipulation of the tumbler lever in conjunc- tion with the nvo adjacent compound gear levers.
The lever positions are determined by reference to the direct reading screwcutting and feed chart. For changewheei combinations see charts on page 12. An additional unit can be supplied giving lever operated selection of English or Metric threads. A range of I5 Metric thread pitches from 0"5 to 7 mm. together with the standard range of 4 to 60 TPI is directly available. The indicator dial cannot be used for metric, B.A. and other special threads when a 4 TPI leads crew is fitted. It can be used for metric threads (divisible into 120) when a 6 mm. pitch leads crew is fitted, but not for special threads, including English and American.
For all speciai threads it is necessary to maintain engagement of leads crew and an electrical reversing switch can be supplied for returning the carriage, enabling repeat cuts to be taken. With the metric gearbox, 30 metric pitches are available having a range from 0"2 to 7 mm. pitch. Extra change wheels can be supplied for Metric/English conversion giving a thread range of 4 to 60 TPI. Change Wheel combinations are given on page 13. (e) Slideso Cross slide and compound slide are fitted with friction grip micrometer dials graduated to read "OOI in.
The compound slide assembly is arranged to rotate through 360 degrees on the graduated cross slide and locking is by means of the two nuts on the swivel slide. Micrometer dials are also available to read 0·02 mm. (d) Apron. Instantaneous engagement and disengagement to both feeds is obtained by the trip lever of the drop Olit worm box situated at the base of the apron. The feed selector knob which is directly below the cross slide handwheel should be pushed in for sliding feeds and pulled out for surfacing feeds. { L (f) TailstocKo Clamping to the bed is effected by the lever at the rear and spindle, quill locking is by means of the pad bolt on top of the tailstock. f ) 9