Drilling Templates
This invention concerns drilling templates in particular but not exclusively for making holes in boards or planks, for example for receiving dowels to make joints therebetween.
One method of joining together planks of timber and the like is to drill holes into the pieces to be joined and to insert dowels into the respective holes to join the pieces together. The two pieces are therefore butt jointed, with the joint reinforced with the dowels inserted into holes in both pieces.
As will be appreciated, in order to achieve accurate joining of the pieces it is necessary to have accurate positioning of the holes in them. Inaccuracies in drilling, and more particularly incorrect positioning of the holes in the respective pieces to be joined results in misalignment of the pieces when they are joined, and in some cases this may even lead to the joint being
impossible to make and/or damage to the pieces when attempts are made to form the joint.
The accurate drilling of holes required to facilitate the accurate joining of workpieces using dowels is a particular problem with wood, where the grain of the wood tends to throw the drill off the intended line, but it is even more of a problem with resin bonded particle boards because such boards have an even more non-homogeneous structure than wood. Whilst the latter tends to be less of a problem when drilling into the faces of resin bonded particle boards, it is a particular problem when drilling into the thickness of the boards from the edges or ends of the boards due to the alignment of the wood particles within the boards.
The above problems can be reduced substantially using drilling machines having a plurality of rigidly fixed drills which produce accurately aligned holes when the workpieces are correctly positioned in the machines. Such machines are used in the factory manufacture of furniture from chip board, coated for example with melamine or a veneer. However, such machines are very expensive and out of the reach of private individuals or small manufacturers.
Various proposals have, however, been made for overcoming the above problem, for example for the do-it-yourself market.
One such proposal is to use a drilling template in the form of an "L" section block which is clamped on to the edge of a board, the template having accurately positioned pre-drilled holes passing through it so that drilling through the holes into the workpiece produces holes in the workpiece which are accurately positioned relative to an edge of the workpiece. Different thicknesses of workpiece are accommodated for by the use of pre-drilled holes of different diameters in the template.
A major problem with such templates is that it is difficult to position them accurately along the edges of boards with which
they are used, with the result that the joints which are formed are often misaligned. In addition, these templates often have only one guide hole of a particular size, and drilling multiple holes necessitates very accurate positioning of the templates for each of a succession of holes which are to be drilled. Since it is difficult to position such templates for the first of a series of holes, it is even more difficult to achieve accurate positioning for a plurality of adjacent holes along the edge of a board.
According to the present invention there is provided a drilling template for drilling a plurality of holes in workpieces, the template comprising a substantially rectilinear bar having substantially flat and parallel opposing faces with a plurality of through holes of a particular diameter therebetween for guiding the drilling of a plurality of holes in the workpieces, and moveable stop means which can be disposed to abut a surface of a workpiece and locate the template relative to the workpiece.
The bars of templates in accordance with the present invention can have a plurality of holes of a particular nominal diameter or they can have two or more pluralities of through holes, each of a particular diameter.
The moveable stop means preferably include a plurality of members which are each pivotal relative to the bar.
Templates according to the present invention preferably include locating means for locating the template relative to a workpiece without the use of the moveable stop means. This can enable the templates to be used at arbitrary positions on a workpiece relative to the edges of a workpiece using the end of the workpiece as a guide or another guide such as a straight edge or batten clamped to the workpiece.
Embodiments of drilling template in accordance with the present invention will now be described with reference to the accompanying drawings in which:-
Fig. 1 shows a perspective view of a first embodiment;
Fig. 2 shows a perspective view of a second embodiment; and
Fig. 3 shows a perspective view of a locating pin for the embodiment of Fig. 3.
The drilling template shown in Fig. 1 consists of a straight and rectangular section metal bar 1 having a plurality of drilling guide holes 2, 3 and 4 of different diameters passing therethrough from one side 5 to the other 6. The differently sized holes 2, 3 and 4, for example of 8, 10 and 12 mm diameter respectively, enable holes of different sizes to be drilled in workpieces, and their axes are positioned at equal distances from each other and from the upper surface 7 of the bar 1. The precise distances of the axes of the holes 2, 3 and 4 from the upper surface will in general be selected according to the thickness of the workpiece which is to be drilled using the template.
Positioning of the template relative to a workpiece is effected using two strips, 8 and 9, which are pivotally mounted on bolts 14 in threads in the opposite ends 10 and 11 of the bar 1, and a further two strips 12 and 13 which are pivotally mounted on bolts 15 in threads in the opposite ends of the upper surface 7 of the bar 1.
Each of the strips 8, 9, 12 and 13 has three working positions, one being shown by full lines and the other two by broken lines (two of the positions for strip 9 being obscured by the bar 1 itself) .
When the illustrated template is to be used to drill holes in a workpiece, the strips 8, 12 and 13 are moved, for example, to
the positions shown in Fig. 1, with strip 9 pointing downwardly. The bar 1 is then clamped on to the workpiece with an edge of the workpiece positioned hard up against the angle formed between the strips 12 and 13 and the face 6 of the bar 1, and with another face of the workpiece positioned hard up against the strip 8. Drilling of the appropriately sized holes can then be carried out using the required holes 2, 3 and 4 in the bar 1.
If further holes are required in the same face of the workpiece, the strip 8 is rotated to the vertical position shown by one of the broken line positions, and the bar 1 is then moved along the workpiece to another position where drilling is to be effected. This latter position can be made equal to the previous inter-hole spacing by the use of a drift inserted into an appropriate one of the holes in the bar 1 and one of the holes which have been drilled in the workpiece. This process can then be repeated as often as desired to make the desired number of holes in the workpiece.
In order to drill holes in a further workpiece so that it can be accurately jointed to the workpiece which has just been drilled, the strips 8, 12 and 13 are all rotated through 180°, strip 9 being left in its original downwardly extending position. The new workpiece is then positioned with an edge hard up in the angle formed between the face 5 of the bar 1 and the strips 8, 12 and 13, and with a face hard up against the strip 8. The new workpiece is therefore positioned in front of the bar 1 rather than behind, the latter having been the case with the first workpiece.
Hole drilling can then be carried out as described above.
By providing the bar 1 with two sets of strips at both ends, the device becomes useable from either end. This can be important, for example, when drilling sets of holes of different diameters from others, thereby enabling the position of the first hole from an end of a workpiece to be selected.
The template shown in Figs. 2 and 3 is substantially similar to that shown in Fig. 1, and so similar parts have been given the same reference numerals. However, instead of rows of holes of different diameters, it has a single row of through holes 16 of the same diameter positioned at the same distance from the upper surface 7, and it also has a further through hole 17. A spiked peg 18 shown in Fig. 3 has a cylindrical shank 19 and a spike 20, the shank 19 being a close fit in the hole 17 for reasons which will be described.
This template can be used in a substantially identical manner to that described for the embodiment of Fig. 1 using the strips 8, 9, 12 and 13 (the broken line positions of Fig. 1 not being shown in Fig. 2) . However, it can obviously only be used to drill holes of a single pre-set diameter.
The template shown with reference to Figs. 2 and 3 can, however, be used to drill holes at arbitrary positions along the length of a workpiece. This can be effected using the strips 12 and 13 to define an angle with either face 6 or face 7 of the bar 1 as described with reference to Fig. 1, after which the template is placed hard up against the workpiece and in a position where holed will be drilled in the desired position on the workpiece. The spiked peg 18 is then inserted into the hole 17 in the bar 1 until that the spike 20 becomes fast in the workpiece. Drilling can then be carried out using the holes 16. This is useful for carcassing.
As will be appreciated, the required left and right hand elements of joints between workpieces can be accurately achieved as a result of drilling into the workpieces from opposite sides of the bars 1, that is as a result of turning the bars 1 over when they are transferred from one edge of a workpiece to the other.
Spiked pegs 18 can also be used with the template shown in Fig. 1 by having the cylindrical shanks 19 of substantially the same diameter as one of the sets of holes 2, 3 and 4 in the bars 1.
They can then be used with the templates of Fig. 1 in a similar manner to that described with reference to Fig. 2.
In addition to being used to drill holes in the vicinity of the ends of workpieces, templates in accordance with the present invention can also be used to drill holes at various places in the surfaces of workpieces. For example, they can be used in conjunction with a straight edge or a batten held in place across a workpiece, for example using clamps, the templates then being moved along the straight edge or batten to positions where drilling is to take place, the various locating strips 8, 9, 12 and 13 being moved to positions where they either assist in locating the templates with respect to the workpiece or to positions where they allow the templates to be slid.
As will be appreciated, when the illustrated templates are to be used to drill holes into the surfaces of workpieces, the templates will be used with either face 6 or face 7 of the bar 1 in contact with the surface to be drilled so that drill bits can pass through the holes 2, 3, 4 or 16 into the workpieces.