GB2389666A

GB2389666A - A cutter alignment tool

Info

Publication number: GB2389666A
Application number: GB0211863A
Authority: GB
Inventors: Jeremy Kent
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-05-23
Filing date: 2002-05-23
Publication date: 2003-12-17
Also published as: GB0211863D0

Abstract

An alignment tool for facilitating the cutting of workpieces to form joints therebetween. The tool comprises a protractor 1 for use with an adjustable square 8, 9, the protractor including locating means 2 for locating the set square 8, 9, and at least one scale 6 for translating angles obtained using the set square 8, 9 into angles to which a workpiece should be set to effect the desired cutting of the workpiece.

Description

( - 1 - 2389666

Cutter Alignment Tool This invention concerns cutter alignment tools, for example for facilitating the making of mitre cuts with radial arm saws, table saws, band saws, router tables and other woodworking machines. Although many of such tools include a protractor for setting the direction of cut, and so desired angles of cut can in general be set relatively easily, problems occur in deciding what the angle of cut should be. Thus, a right angled mitre joint between two workplaces can be formed by setting the direction of cut at 45 to a guide line and cutting the workplaces at this angle.

However, if the angle of the mitre joint is not a right angle, setting the angle of cut causes problems because although the tool can be set to a desired angle of cut using the protractor, there are difficulties in establishing the size of this angle.

This is a particular problem, for example, with cutting skirting boards and picture rails for old buildings where walls are often not at right angles to each other.

Adjustable set-squares consisting of two straight arms pivotally connected at one end by a bolt with a wing nut to lock the arms

( - 2 at any angle can readily be used to copy the angle between two surfaces. However, establishing the angle between the arms in degrees is difficult, and so, therefore, is the half angle required to effect a mitre cut. More particularly, the construction of conventional adjustable set-squares makes this difficult because they generally consist of one arm in the form of a block with a longitudinal slot in which is located a metal strip which forms the other arm.

According to the present invention there is provided a alignment tool for facilitating the cutting of workplaces to form joints therebetween, the tool comprising a protractor for use with an adjustable set-square, the protractor including locating means for locating the set-square relative thereto, and at least one scale for translating angles obtained using the set-square into angles by which the workplace cutter should be set to effect cutting of the workpieces.

The protractors of alignment tools of the present invention will in general have at least two scales for translating angles obtained using the set-square into angles by which the workplace cutter should be set to effect cutting of the workpieces, one of such scales being for setting the angle of cut relative to a vertical axis when the workplaces are on a horizontal surface, and the other being for setting the angle of cut of the workplaces relative to an edge of the workpieces.

The protractors preferably include a scale for showing the actual angle to which the set-square has been set.

An embodiment of device in accordance with the present invention will now be described with reference to the accompanying drawings in which: Fig. 1 shows a plan view of the device; and Fig. 2 shows a conventional adjustable set-square.

The device shown in Fig. 1 is generally in the form of a semi-circular protractor 1. However, unlike a conventional protractor, the radial centre is not present. Instead, a recess 2 is provided in the thickness of the device, the recess 2 providing two datum surfaces 3 and 4 which will subsequently be described in more detail. The protractor 1 also has three angular scales 5, 6 and 7 which subsequently will also be described in more detail.

The adjustable set-square shown in Fig. 2 is of conventional design consisting of a wooden stock 8 with a central slot (not shown) in which a metal blade or arm g is positioned, the stock 8 and the blade 9 being pivotal about a bolt 10 with a wing nut 11, tightening of the wing nut 11 on the bolt lo serving to clamp the blade 9 in the slot in the stock 8.

The device shown in Fig. l is used as follows.

The adjustable set-square shown in Fig. 2 is used in conventional manner to establish an angle between two surfaces.

It is then placed in the recess 2 in the protractor with the end of the stock 8 remote from the bolt 10 abutting the datum surface 3 and one side of the stock 8 abutting the datum surface 4. The blade 9 is then positioned over the scales 5, 6 and 7 on the protractor 1.

The reading on the scale 5 shows where edge 12 of the blade 9 crosses it indicates the angle between the stock 8 and the blade 9, this being the measured angle.

The angles shown by the scale 6 and 7 indicate two different types of cutting angle.

That shown by the scale 6 indicates the angle to which the cutting tool needs to be set relative to conventional cutting angle scales on the horizontal bed of a mitre saw, that is the angle of the saw blade relative to an associated guide surface with a right angle cut being indicated by zero, with the blade

- 4 in a vertical plane. Such cuts would be required, for example, to join two pieces of skirting board where the associated walls; are not vertical.

That shown by the scale 7 indicates the angle tilt to which the cutting tool needs to be set relative to a vertical plane using a horizontal cutting bed in order to achieve different angles of mitre cut, for example between skirting boards around a corner.

As will be appreciated, the adjustable set-square does need to have dimensions which correspond to those of the protractor 1 in order to avoid errors in the indicated angles, and so they will usually be supplied as a kit. i

Claims

- 5 - Claims

1. An alignment tool for facilitating the cutting of workpieces to form joints therebetween, the tool comprising a protractor for use with an adjustable set-square, the protractor including locating means for locating the set-square relative thereto, and at least one scale for translating angles obtained using the set-square into angles by which the workplace cutter should be set to effect cutting of the workpieces.

2. A tool according to claim I, wherein the protractor has at least two scales for translating angles obtained using the set-square into angles by which the workplace cutter should be set to effect cutting of the workpieces, one of such scales being for setting the angle of cut relative to a vertical axis when the workpieces are on a horizontal surface, and the other being for setting the angle of cut of the workpieces relative to an edge of the workpieces.

3. A tool according to either of the preceding claims, wherein the protractor includes a scale for showing the actual angle to which the setsquare has been set.

4. An alignment tool for facilitating the cutting of workpieces to form joints therebetween, the tool being substantially as herein described with reference to the accompanying drawings.