Instruction Example 2.5.: Joining of the Window Posts

This instruction example teaches how to join the window posts for an upright roof window with lean-to dormer roof.

Constructional details

- The opening in the roofing has already been made.
- Window posts are to be joined with corner tenons.
- Cross sections of timbers are shown in the workshop drawing on page 7.
- Window posts are cut to a length of 1250 mm.

Figure

Hand tools

Hammer, engineer's square

Measuring and testing means

Folding rule

Auxiliary accessories

Trestles (one ell), pencil, marking gauge, workshop drawing

Necessary previous knowledge

Measuring, scribing, angling, use of marking-out marks, reading of drawings

Explanations to the working drawing

The figures 2 to 14 represent the steps as per sequence of operations

Sequence of operations	Comments
1. Prepare the working place, erect the trestles with the correct distance.	Check the trestles for firm standing and stability!
2. Inspect the window posts, decide on the joining side and mark with marking-out mark.	Joining side "I" shall have an even face! Any slight camber is to be used as outside face of the window post and to be marked with "II".
3. Put the window posts closely together on the trestles.	Put them so that the face marked with "II"" is visible from above! Place the joining sides so that they remain visible (see V)! Hammer with gentle hammer blows so that the left ends of the timbers are about flush!
4. Scribe section lines at left ends of window posts and mark with marking-out mark.	Go only as far to the right as to permit a right-angle section to be produced!
5. Angle the section line at both joining sides, scribe and mark-out.	Use engineer's square!
6. Measure-in and scribe window post length, starting from the section line and measuring to the right, and mark with the marking-out mark.	Window post length = clear window height plus two tenon lengths! Use engineer's square and place it exactly! Clear window height is shown in Instruction Example 2.4!
7. Angle the section line at right ends of window posts at the joining sides, scribe and mark-out.	Use engineer's square!
8. Measure-in and scribe the corner tenon length at both section ends on timber face "II", measuring towards the centre.	Scribed line must be in parallel with scribed line of steps 4. and 6. above!
9. Angle and scribe corner tenon length at the two joining sides.	Place engineer's square exactly and scribe thin line!
10. Move the window posts apart because now each of them is to be separately scribed.	Select the distance so that scribing between the timber faces marked with "III" is possible without hindrance!
11. Scribe the comer tenon thickness at the left ends of the window posts.	Place sharp pencil exactly at marking gauge end face and scribe from the joining side! Do not cant the marking gauge when scribing!
12. Scribe the comer tenon thickness at the right ends of the window posts.	See step 11. above!
13. Measure-in and scribe corner tenon width.	Scribed line must be in parallel with timber face "II"!
14. Mark wood to be sawn out at all four comer tenons.	Scribe crossing diagonal lines!
15. Angle the section lines at both ends of the window posts onto the timber faces "III" and "IV", scribe and mark with marking-out mark.
16. Work the window posts.
17. Take the worked window posts off the trestles and store them outside the working area.

Joining of the window post