The speed of the lathe must be adjusted to suit the size, balance, length and condition of the timber being turned. The larger the work diameter, the slower the lathe speed needs to be. If the piece you're turning is out of balance, then you need to start turning at a slow speed, until you've evened it out a bit. If the work piece is long in relation to its diameter, then it is likely to 'whip' - or, technically to 'whirr' - if the lathe speed is too high. Finally, look at the timber itself. Are there loose bits of bark? Is it in the process of decay? Are any parts of it unsound? Is it homogeneous - that is some bits heavier than others (usually one side could be heavier than the other due to differing densities of sapwood and heartwood)? If the answer to any of these is 'Yes', then you probably shouldn't be turning that wood at this stage of your development! If you must, then take extreme care and start off very - very - slowly and carefully.
The tool must rest firmly on the tool rest before it is brought into contact with the rotating wood and must never be lifted off the tool rest as long as it is in contact with the timber.
All woodturning tools are ground with a bevel to produce the cutting edge. This bevel must be in contact with the timber at all times whilst the tool is cutting, thus giving support to the cutting edge and controlling the depth of cut. (The exception to this is in the case of scrapers and certain specialist tools, but let's keep it simple for now.)
The section of the cutting edge, which is in contact with the work, must be in line with the point of contact with the tool on the tool rest to gain adequate support. This ensures that the tool cannot be twisted, or rotated, by the force of the timber against the tool acting to one side of the point of contact between tool and tool rest.
Always cut the wood in the way that it likes to be cut. This is maybe the most frequently repeated phrase in woodturning instruction and owes its origin to Frank Paine, the 'Father of Modern Woodturning'. In essence, it means always cutting 'downhill'. That is, from the largest diameter to the smallest diameter. Think about the action of a plane on timber: you always cut 'with' the grain - if you don't, the wood splinters up and leaves a rough surface. The same applies in woodturning.
When using 'scraping' tools, keep the point of cutting below the centreline of the work piece when working on the outside and above the centreline when turning the inside of, for instance, a bowl. These tools are always used trailing slightly (5 degrees) below the horizontal, in side elevation, and flat on the tool rest in section/end elevation.
Always remove waste from the areas of most waste, first. If you're turning off a corner, start removing wood at that corner and gradually work your way back along the work piece until you've reached the desired form. Don't expect to push your way into the timber and remove all the waste in one 'go'
