Lathe
SIZE: Maximum distance betsceen centres: 20 to 40in.; From centre in bed: 3 to 12in.
MATERIAL: Various
ACCESSORIES: Wood turning tools
USE: To make turned wooden objects
The lathe is used to "turn" wood into round sectioned objects such as chair legs, bowls, door knobs and so forth. The work is revolved at high speeds against the cutting edges of various wood turning tools or chisels. The basic function of all lathes is the same, although various models differ in speed and size.
If you don't do enough turning work to justify the expense of a lathe, convert an electric drill into a small bench lathe with a special attachment.
How the lathe works
Work being turned "between centres" is held between the head stock and tail stock. Both stocks are located on the lathe bed which aligns the centres. The head stock, fixed at the left band end of the bed, houses the motor which drives the spindle. The spindie is threaded to take a chuck, face plate, or a
driving centre spur which grips and turns the work. A face plate is fitted to the head stock spindle to turn bowls, trays and so on. For larger face plate work, the plate can be fitted on the other end of the spindle on some lathes.
The other end of the work is held by the tail stock which is free to move on the bed to accommodate work of various lengths. The tail stock has an adjustable spindle with a cone shaped centre point.
A tool rest is mounted on the bed at a convenient position along the work.
Turning between centres
Prepare the wood for turning by first cutting to length. Remember to allow an extra |in. at each end of the workpiece to take the drive and tail stock centres. Mark the centre on each end by drawing diagonal lines. Take the point where the diagonals cross as your centre.
Preparing square stock
Use a compass to draw a circle on the end grain to match the maximum diameter of the ti'orkpiece. Plane off the four corners down to this line to make an octagon.
To mark the centre on round stock, use a centre finding gauge.
Position the driving centre in one end of the work and drive the "teeth" into the end grain with a soft mallet
Setting up the work
Remove the centre and set it up in the drive spindle. Locate the work on the drive centre and slide the tail stock to within lin. of the other end of the work. Lock it on the bed, and turn the tail stock feed to locate the centre point in the centre of the work.
Check that the work revolves freely without being slack between the centres, and tighten the clamp on the tail stock. Grease the tail stock centre lightly to decrease friction.
Set up the tool rest 1/8in. from the work and 1/8in. below the centre line and lock it in position. Revolve the work by hand to insure that it will not hit the tool rest.
Special cuts
Use shaped grooves, beads and coves, singly or grouped together, to make decorative effects. Files and rasps can be used as well as normal tools.
Square cut-out
Chisel two " V" cuts on the waste side of the line to the depth of the cut. Remove the waste between the cuts with a gouge. Finish with a chisel.
Hollow
Use a gouge. Starting at the centre, swing it in an arc in both directions, waking deeper and wider cuts as you progress.
Bead
Make "V" cuts at each end. Round off the bead with a chisel, pivoting it on the rest.
Checking the shape
Use a profile gauge or cardboard template to check a turned shape as it progresses especially on repeating patterns. Check the diameter periodically with calipers.
Wood turning tools
For information and techniques for using turning gouges, chisels and parting tools, see the section on wood turning tools.
Sanding and finishing
Remove the tool rest and increase the speed of the lathe. Hold a strip of abrasive paper against the back of the work while it is spinning. Polish the work by running a cloth dampened with the finish along the work while it is spinning.
Face plate turning
Mark the centre of the work with diagonals and draw a circle to indicate the diameter of the face plate. Screw the plate to the work, centreed on the circle, with short, heavy screws. Check that the screws will not hit the chisel during the turning operation.
If the screw holes would be visible on the finished work, glue a wooden plate to the underside of the workpiece to take the screws, sandwiching a layer of thick paper between. The two pieces of wood can eventually be split apart along the paper line.
Cut off the corners of the workpiece to reduce the waste before attaching the plate to the drive spindle on the lathe.
Set the tool rest parallel to the axis of the work and shape the outside profile using a template to check the shape. Finish with sand paper. Set the rest parallel with the face of the work and hollow out the inside with a gouge working from the edge inward. Smooth the surface with a round nosed chisel before finally sanding.
Safety precautions
Keep the tools sharp for better, safer work.
Stand to one side of the lathe when turning on the machine.
Never make adjustments to the lathe while it is running.
Avoid loose clothing and neckties. Tie back long hair.
