I have acquired a lathe and am unsure about the controls. What should I do before starting it up and trying to use it?
The very best way is to get the seller to demonstrate it for you and point out any important points. If this is not possible, try to find somebody locally who owns the same machine and ask for help. In addition, check to see if there's an online users' group; Yahoo.com have many, for a wide variety of machines (just Google "yahoo users groups). Members are generally enthusiastic and willing to assist. Failing any success and you find yourself alone, the following might help.

First, to understand what is being advised, you'll need to know the names of the various parts of the lathe and what they do. If you are a beginner, and unsure, some homework on these pages will help: "How it works, Parts and Functions"

As you work through the controls it's a good idea to mark, with labels, what they do. If they wont stick to an oily machine, as a temporary measure tie tags on with string - this tip will save you much time and trouble and - potentially - a disaster as you later select the wrong lever because you've forgotten what it does..

Obviously, lathes differ enormously in the details of their controls, so it's very difficult to give specific advice; indeed, it's difficult to even give sound generalised guidance, so do proceed cautiously.

First: see if you can obtain an Operation. Maintenance and Parts Manual from https://www.store.lathes.co.uk/print/ It's a wise investment.

Second: why not get a friend to video what you are doing? It can make a handy reference and check.

If no literature is available, sound general advice is never to switch the lathe on, but first experiment with the levers on the headstock - the very place where you are most likely to damage things by following the wrong procedure.

Before starting, take off what might be a large cover on the left-hand side of the lathe; this will expose the changewheel drive to the screwcutting gearbox (or direct to the leadscrew) and let you see what happens when controls are moved. With the cover off check to see that the previous owner has not just thrown things together and that the various gears are not loose on their studs, or the studs loose on the holding bracket. If they are and you start the lathe much mechanical marmalade could result

Move each lever through one position at a time and turn the chuck by hand at each location noting what happens. Make sure that you check all the levers. Occasionally levers are in pairs with one only able to be moved when the other is in a "neutral" position - these are usually the spindle-speed levers. One lever - often on the top of the headstock - might be to operate a spindle clutch: in one position the chuck will spin freely, in another the drive will be engaged and the chuck harder to turn. Sometimes, moving the lever in the opposite direct will engage a spindle brake - handy for bringing heavy jobs to a halt.

Two very important controls are for the "tumble-reverse" unit (to understand how this works, see the special section here: http://www.lathes.co.uk/tumblereverse) and, on some lathes, backgear (a special section is also devoted to this: http://lathes.co.uk/backgear) Under NO circumstances must either of these controls be moved when the spindle is running

Having checked through all the headstock levers, move on to the screwcutting and feeds gearbox. Again, move each lever though all its possible positions and turn the chuck to see what happens at each…..getting fed up? OK, but it's vastly cheaper than starting the lathe up and smashing a set of gears or breaking a casting…

One some lathes both a leadscrew and power shaft are present - with the former able to be disengaged by use of a sliding control or lever. This mechanism is usually mounted just outboard of the screwcutting gearbox.

Next, the carriage assembly: repeat the procedure of moving the controls but this time also try the carriage handwheel and the cross-feed handle. It's wise to turn the chuck as well, though it's often the case that it will have to be rotated ten or twenty times for you to notice anything happening. A typical apron looks like this

With all the lever positions checked now is the time to attend to lubrication: see this page for advice

Now comes the moment of truth, switching on - but before you do, is the chuck on securely? Legion is the number of lathes started with a loose chuck to the detriment of life and limb...even small ones can hurt. A lot.

Select a low spindle speed: stand away from the chuck and switch on. Does the motor run but the chuck not turn? Engage the clutch - if you've discovered the control. Clutch engaged but no difference? You've probably put one of the spindle-speed levers into a neutral position. Switch off and check the lever - or combinations of levers; remember, some have to be set relative to each other (as one some older Harrison lathes) to work.

Most important: is the chuck running anti-clockwise viewed from the tailstock end? If clockwise, the switch has been selected to reverse (switches sometimes loose their markings after years of use).

With the lathe running on a low speed let it warm up for a while. Switch off and engage the drive to the screwcutting and feeds' gearbox, selecting a medium rate of feed according to the marking on the gearbox chart. Next, before starting the lathe, ensure that the carriage can be moved freely up and down the bed by using the large carriage handwheel.

Start the lathe. Is the leadscrew running? And the power shaft? Now it's time to try, one at once, the apron controls and note what happens. A point that often confuses beginners is the direction of travel of the power cross feed (if fitted). On the apron will be a 2-position lever to make the carriage move either along the bed and the cross slide across it - and there appears to be no way of making the parts move in the opposite direction i.e. the carriage moves towards the tailstock and you want it to move towards the chuck - or the cross slide moves outwards and you want it to move inwards. The change of direction is usually controlled by the tumble-reverse mechansim - but remember, before moving the control,  the lathe must be stopped

Once you have the lathe running and understand what the controls do, you'll want to use it. If a beginner it's as well to be aware that machine tools can be dangerous.  While somebody seems to find a novel way of killing or maiming themselves every week in industry, this page will help avoid some of the common mistakes made with a lathe. It also has many useful ideas for getting the best from a machine. It's worth a close read.

Can you add to this page? Do let me know.