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		Boring - Course: Manual woodworking techniques. Instruction examples for practical vocational training (Institut für Berufliche Entwicklung, 23 p.)
			(introduction...)
			Preliminary Remarks
			Instruction Example 5.1.: Holes of Limited Depth
			Instruction Example 5.2.: Bit Stand
			Instruction Example 5.3.: Screw Holes
			Instruction Example 5.4.: Through Holes
			Instruction Example 5.5.: Stool

Instruction Example 5.3.: Screw Holes

Wood screws of larger diameter and greater length call for pre-bored holes in the wood. This is necessary for many workpieces. Instead of the board door described here, any other workpiece with wood screws maybe used for practising.

Material

Boards, cross and diagonal braces of soft or hard wood

Dimensions:

Designation

Pcs.

Thickness

Width

Length

mm

mm

mm

Boards

6

20

150

1900

Cross braces

2

25

120

860

Diagonal brace

1

25

120

1600

All parts are planed and sawn to size, the diagonal brace is fitted to the cross braces.

Tools, measuring and testing means

Bit brace, twist drills, gimlet with ring handle, wood countersink, marking gauge, folding rule or measuring tape, try square, pencil, hole depth setter

Auxiliary accessories

Workbench or trestles, screw clamps, supporting pieces of wood

Necessary previous knowledge

Measuring and scribing, mode of action of wood screws

Explanations to the marking drawing

Board door with 2 cross braces and 1 diagonal brace, scale 1:10

Sequence of operations

Comments

1. Prepare the working place.

Check the tools.

2. Put the individual parts of the board door on the work bench or on trestles, arrange them and clamp them by screw clamps.

Check the arranged boards for squareness by means of the try square.

3. Put the cross and diagonal braces on the board door, arrange them acc. to the given sizes and clamp them by screw clamps.

Diagonal brace must be tightly fitting between the cross braces.

4. Scribe the screw line with the marking gauge and determine the hole points.

Distances and arrangement of the screw holes are given in the drawing.

5. Select the drill and chuck is in the bit brace.

Drill diameter to be 2 mm less than the diameter of the wood screws used. If a gimlet with ring handle is used, chucking in the bit brace is not necessary.

6. Mount the hole depth setter.

Hole depth to be 5 mm less than the screw length.

7. Drill the holes.

Vertical boring axis is important!

8. Release the drill and chuck the countersink (rose bit).

If screws with countersunk heads are used, countersink the holes according to the size of the screw head.

9. Countersink the holes.

10. Check the results.

Check if the wood screws can be easily screwed into the wood.

Screw Holes

Designation	Pcs.	Thickness	Width	Length
		mm	mm	mm
Boards	6	20	150	1900
Cross braces	2	25	120	860
Diagonal brace	1	25	120	1600

Sequence of operations	Comments
1. Prepare the working place.	Check the tools.
2. Put the individual parts of the board door on the work bench or on trestles, arrange them and clamp them by screw clamps.	Check the arranged boards for squareness by means of the try square.
3. Put the cross and diagonal braces on the board door, arrange them acc. to the given sizes and clamp them by screw clamps.	Diagonal brace must be tightly fitting between the cross braces.
4. Scribe the screw line with the marking gauge and determine the hole points.	Distances and arrangement of the screw holes are given in the drawing.
5. Select the drill and chuck is in the bit brace.	Drill diameter to be 2 mm less than the diameter of the wood screws used. If a gimlet with ring handle is used, chucking in the bit brace is not necessary.
6. Mount the hole depth setter.	Hole depth to be 5 mm less than the screw length.
7. Drill the holes.	Vertical boring axis is important!
8. Release the drill and chuck the countersink (rose bit).	If screws with countersunk heads are used, countersink the holes according to the size of the screw head.
9. Countersink the holes.
10. Check the results.	Check if the wood screws can be easily screwed into the wood.