How to Use Lathe Attachments

Using lathe attachments

Lathe attachments made to fit all makes of power drill are only suitable for light work. For the best results use a variable speed drill set at 900 rpm. Ensure that the lathe bed is firmly fixed to the workbench or table top.

The timber to be turned is held between the fixed head-stock and the adjustable tail-stock.

The tool rest, which can traverse along the bed, is used for supporting the chisel-type turning tools against the rotary movement of the work. ‘Attachment’ turning tools are smaller than the standard size.

Flat objects, such as bowls, lids or plates, are turned on a face plate mounted on the head-stock; the tail-stock is not used for this type of work.

 

On some lathes the face plate can be screwed on to the reverse side of the headstock. This increases the size of objects which can be turned, as there is no obstruction from the lathe bed below. This arrangement calls for a tool rest which can be swivelled out from the main body of the lathe and brought into position behind the head-stock.

Basic tools for turning

The three main types of turning tool are the chisel, gouge and parting tool. All are hand-held and are supported on the tool rest while actually turning.

When turning long objects between the two centres, use timber that is 3-6 mm (1/8 – ¼ in) thicker than the maximum dimensions required. For instance, 50 x 50 mm (2 x 2 in) sawn timber will turn to a diameter of 47 mm (1-3/16 in) if centred accurately. The method of doing this is described below.

Concave sections are cut with gouges, convex and straight sections with gouges and chisels, square shoulders with chisels or parting tools and beads with chisels. Practice will soon reveal the scope of the tools and the best way of handling them.

Gouges are sharpened on a normal oilstone by rubbing them in a figure-of-eight pattern, at the same time rocking the blade from side to side with a wrist-turning action. This ensures that the entire outer convex edge of the tool is correctly shaped and sharpened. The inner concave side is honed with a slipstone.

The turning chisel has a curved side elevation and is given an edge in much the Templates can be half length, as shown, or full length. The diameters marked at each end of a template are first turned to size on the work. The template is then used continually to check the work as the waste between the end diameters is gradually removed.

Turned work is checked for correct final inside and outside sizes with callipers.

‘Tight-joint’ callipers are adjusted by tapping the arms closer, or farther apart, but on the screw adjustable type this can be done more accurately by turning a nut. Slightly more expensive are the screw adjustable callipers with slip cone nuts which allow for rapid resetting.

Same way as a normal woodworking chisel, but regrinding or coarse honing must preserve the original curve.

Parting tools are sharpened in the same way as chisels. Good reuts are impossible unless tools are sharp and correctly shaped.

Templates, for establishing the exact contours of the work to be turned, can be easily made up from hardboard, plywood or cardboard. They are especially useful for repetition work, eg. turning four legs for a table.

Preparations for turning

Flat objects for turning can be screwed to the lathe face plate or can be glued to a block of wood which is then screwed to the face plate. When using a block, clean up the base of the work, stick paper on with Scotch glue and then glue it to the block.

When turning is completed, the work can be knocked off the block; the paper lining will split, leaving a surface which is easily cleaned.

To prepare a length of timber for turning between centres, cut it to length, not forgetting to allow for the head and tail lathe centres, ie. plus 25 mm (1 in). Make sure the timber is square in section, then mark off diagonals on each end as shown. This will establish the exact centres. Continue by marking off octagons on each end and shape the timber to them by sawing or planing.

Next drill a shallow 3 mm (1/8 in) diameter Hole in the centre mark at each end. Take the centre-piece out of the head-stock, insert it into one of the drilled holes and tap it firmly into the end grain with a block of waste wood. Remove the centre-piece, put it back in the head-stock, offer the timber up to it and bring the tail centre-piece into position so that the work is held.

If the tail centre-piece heats up while the lathe is turning, it may either be fastened too tightly or require lubrication.

With the work held in the lathe, traverse the tool rest to the tail-stock end and adjust its height so that the tip of a tool resting on it touches the work just above an imaginary line drawn between the two centres.

Turn the work from its octagonal section down to the maximum final diameter required for the whole length of the tool rest. Then move the rest towards the tail-stock, and carry on turning and resetting until the work is completely round.

Whenever possible, work from left to right — or if you are left-handed, from right to left. Always hold the handles of your turning tools firmly against your hip and press the blade down on to the tool rest with the other hand.

24. June 2011 by admin
Categories: Power Tools, Tools | Tags: , | Comments Off on How to Use Lathe Attachments

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