Jigs and Guides

From time immemorial woodworkers have made their own bench hooks, shooting boards and mitre boxes. Consequently they are rarely shown on illustrations or included in inventories, and have no official history. The profile gauge is a recent invention; one of the earliest examples occurs in a Swedish catalog of 1957. Until the arrival of the power drill, doweling jigs were also highly specialized; so much so, that one type which was used about a century ago for doweling sash bars has only recently been identified. Although about a dozen were known, their use had been completely forgotten until now.

Mitre Box

OTHER NAME: Mitre machine

SIZE: 9 and 12in.

MATERIAL: Beech, cast iron.

USE: To guide a saw to cut accurate mitre and right angle joints

A mitre box is a jig which guides the blade of a back saw to cut 45° mitres and accurate squared ends.

The simplest versions are open wooden boxes with slots on two sides into which the saw blade fits. Brass guides are sometimes fitted on the top edge to reinforce the slots.

Mitre box with reinforcing:

More sophisticated metal mitre boxes have tall guides which support the back saw and can be adjusted to cut angles for four, five, six, eight and twelve sided figures.

Using the mitre box

The work is laid in the jig and pressed against the far sides by the free hand. To protect the wooden base, raise the work on a piece of scrap lumber and align the mark indicating the cut with the edge of the appropriate slot. Make certain that you are cutting on the waste side of the line.

Make the first cuts with backward strokes, lowering the blade to horizontal as the cut progresses.

Mitre block

A simpler guide, known as a mitre block, is a one sided mitre box.

Metal mitre box

The work is clamped to a guide and an adjustable stop sets up work for repeated cutting.

Bench Hook

SIZE: 6 x 10in.

MATERIAL: Beech

USE: To support lumber whih. it is sawn across the grain

Bench hooks have two blocks accurately jointed at right angles to the long edges. There is one on each side. One block hooks over the front edge of the bench while the work is held against the other block. Either side can be used to support the work while it is sawn.

working with bench hooks

Hook one side of the bench hook on the front edge of the bench and hold the work against the other block.

Shooting Board

OTHER NAME: Mitre shoot board

SIZE: 30in.

MATERIAL: Beech

USE: To guide a plane to cut end grain of lumber to 90° or 45°

The shooting board is a jig which guides a plane in relationship to the work so that the blade is square to the planed edge. It consists of two boards which are set parallel to each other to form a rabbet. The upper board has a wooden stop let into the surface at right angles and secured with screws. The plane rests on its side on the lower board, the rabbet acting as a guide for the sole of the plane. It is particularly useful when planing the end grain of solid lumber.

A mitre shooting board has a 45° angle stop for planing the end grain of lumber to make a 90° mitre joint.

Using the shooting board

Use a sharp, finely set plane. Set the blade accurately so that the cutting edge is parallel with the sole of the plane. Candle wax applied to the sole and side of the plane will help it to run smoothly.

Clamp the shooting board to the top of the bench between two bench stops. Hold the work firmly against the stop so that it projects to touch the sole of the plane. The stop prevents end grain splitting.

The long edges of thin panels can be accurately planed on a shooting board, as can a stack of veneers clamped to the board under a wood strip.

With the work held against the stop, slide the plane up and down the board keeping it pressed into the rabbet. Back up thick work with scrap wood.

Doweling Jig

OTHER NAMES: Drill guide, dowel guide, dowel locator

SIZE: Various

MATERIAL: Aluminum alloy, steel

USE: To align matching holes for a dowel joint and to guide the drill bit square and true

The simplest method of aligning holes for a dowel joint, and one that has been used traditionally for many years, is to mark both halves of the joint simultaneously with a doubled pointed nail or pin. This might be the heads of nails laid on their sides, or a nail driven into one half of the joint and the head cropped off to leave a sharp peg projecting.

Dowel locators are available which leave a clear mark and have a collar which prevents the pin being driven into the end grain of the lumber before it has marked the side grain.

Mark out the hole centres on the work and press a locator into each centre. Position the second half of the joint, resting it lightly on the locators until it is accurately aligned, and press firmly on to the protruding points. Remove the locators and drill the holes.

Nails and locators still need to be drilled square and true into both halves of the joint. A doweling jig will align the centre of the drill bit with the hole centre and guide the bit at the same time. Simple jigs clamp onto the work and align a steel bush with the hole centre. The bush (available in various sizes), matches the diameter of the bit and keeps it in a vertical position during the drilling.

A more versatile jig will guide the bit and will also align the holes in the two halves of the joint. It has two steel rods, which carry a fixed head or fence from which all measurements are taken, sliding bush carriers, which can be clamped in the required position according to a graduated scale, and a movable head or fence which clamps the tool on the work. Side fences on the bush carriers position the bushes relative to the work thickness,

Making dowel joints

Position nails on one half of the joint. Align the other half and press on the nail to produce a matching mark.

Simple marking jig

Make a simple jig from two short lengths of wood to accurately align the two halves of a dowel joint.

Screw the lengths of wood to the bench at right angles to each other. Holding the two halves of the joint against the wood pieces, push the cut off pins into the upright to mark the positions of the dowels.

Making a butt joint

A simple butt joint in softwood is jigged to drill the end grain first. Set up the jig components and clamp the adjustable head just clear of the wood width.

Drilling end grain

Position the jig on the work with fences and fixed head in contact with face side and edge, and clamp the tool in place with the clamping screw. Position the drill bit in the bushes and drill to the required depth. After you finish drilling the end grain it will be necessary to drill the side grain in order to complete the joint.

Drilling side grain

Remove the adjustable head and invert the jig before clamping it onto the other half of the joint. Leave a space between the bush carriers for the clamp when the tool is first set up. Drill as before and glue up the joint.

Drilling dowel joints

This type of jig is good for drilling dowel joints in composite boards. With the first board set up in a vise, adjust the jig as before and clamp it to the board. Drill first two holes.

Position the second half of the joint in the jig, butting it against the fixed head and fences, and secure with the upper clamping screw. Release the bottom screw and invert the board to drill the holes in the second half. Repeat for other holes or fix additional carriers to the rods and drill all the holes at once.

Drilling longer boards

For boards longer than the rods, use the jig without either head, and hold it on the edge of the board with the fences pressed against the face side. Locate the first bush over a dowel fitted into the previously drilled hole to accurately space the holes along the board.

Using a similar set up, the jig can be used to drill various butt joints, mitre joints, and edge to edge joints.

Profile Gauge

OTHER NAME Shape tracer

SIZE: 6in.

MATERIAL: Steel and/or plastic.

USE: To reproduce a shape and act as a pattern for cutting to fit

The profile gauge is a row of tightly packed steel needles. Pressed against an object, these slide backward to reproduce the shape. It is particularly useful where one material must be cut to fit another, such as vinyl floor tiles around pipework or door mouldings.

Before using the profile gauge, press it against a flat surface to align all the needles.