Hand Tools for Measuring and Marking

Squares, bevels and templates

Try try-square is a vital tool, for marking out and checking right angles. Without one it is impossible to true up any edge.

The traditional try-square has a wooden or plastic stock and metal blade. A wooden-stock square may not always be true, since varying moisture content in the stock causes it to swell or contract.

To check a square for true, draw a line along the blade from a straight-edge, turn the blade over, and check that the blade coincides exactly with the drawn line.

The metal combination square will always stay accurate. It also has the advantage that it can be used for marking mitres (angles of 45°) as well as internal, and external right angles.

Always hold the stock firmly against the work when using a square. Mark lines against it with a pencil or marking knife.

Other useful marking tools are the sliding bevel, which has a movable blade for marking and checking complex angles, and the dovetail template, which has sides with a 1-in-6 or 1-in-7 taper.

Gauges for marking and cutting

Gauges are for marking or cutting lines parallel to a face or edge.

The marking gauge is a necessary basic tool, for setting out for rebates and a variety of joints. To use it, you set the head the required distance from the pin, tighten up, then draw it along the edge so that the pin marks a line parallel to the edge.

The cutting gauge is similar to the marking gauge but with a cutting blade instead of the pointed pin The blade is held in place by a wedge and must be kept sharp by honing. Use it to cut thin materials such as light plywood, cardboard and thin plastic, and to give a clear mark, particularly across the grain on wood.

The mortise gauge is a more elaborate version of the marking gauge which gives two parallel lines of varying distance. As its name implies, it is for marking out mortise and tenon joints: you set the two pins to the width of the chisel (which should also be the width of the mortise) then set the head so that the pins will mark two lines, each the same distance from the edge of the wood. The width of a mortise should be about one-third of the width of the wood it is being cut in

Handle all types of gauges the same way when using them: first push the gauge lightly along the wood, holding it firmly against the edge, then make a firmer, stronger stroke to give a clearer marking.

If the gauge tends to wander, pull it instead of pushing.

Rules, straight-edges and dividers

A 1 m/3 ft rule or 1 m/3 ft combination four-fold rule is the woodworker’s basic tool. Metric graduations are in centimetres and millimetres, imperial in inches which are sub-divided into eighths and sixteenths. The more simple the rule, the better: types with protractor hinges and built-in spirit levels are of limited value and useless if a break occurs at the hinge.

Always use the same rule for measuring a space and for measuring up the wood to fit, as there may be some slight variation between rules.

Never use a dressmaker’s tape for woodwork.

A little ingenuity will allow you to use a rule for jobs other than straightforward measuring. To divide a narrow board into six equal parts, for example, hold the rule at an angle across the board so that one end lines up with one edge of the board and the 6 in mark with the other; make a mark where the figures 1 to 5 occur to give six equal divisions.

Steel straight-edges are made with or without measured graduations from 300 to 2000 mm and 1 ft to 6 ft. Use these to check for flatness and as a guide for cutting against with a marking knife.

Checking a surface for level is done with a spirit level. The longer the level, the better check it will give over a wide area, though obviously a small level is better for confined spaces.

Dividers are useful for marking off a series of odd dimensions: simply set the dividers to the dimension on a rule, then mark out with the dividers at the constant setting. Dividers can also be used as compasses to mark a circle. They have the advantage over compasses in that they give a scratched line which is accurate, as,unlike the pencil point used in compasses, the steel points do not become blunted.

To avoid a centre hole in the wood when using dividers, lightly glue a piece of thin metal or wood where the centre point of the dividers is to be placed and work from that, removing the padding piece immediately afterwards.

Apart from their obvious uses, compasses are used to mark a piece of wood for shaping to fit an uneven surface, such as a wall: hold the wood upright, about 10 mm (f in) from the wall, then run the compasses down, the point on the wall, the pencil marking the wood to the exact contour of the wall. Keep the wood steady by putting packing pieces between it and the wall, and make sure that it is upright.

Steel tapes of 2 m/6 ft and 3 m/10 ft have a loose lip at the end which hooks over the wood or butts up against it to assist accurate measuring. Longer steel tapes have a ring fixing at the end; these are not accurate enough for small work.

24. June 2011 by admin
Categories: Hand Tools, Tools | Tags: , , , | Comments Off on Hand Tools for Measuring and Marking

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