Question 3
(a) Make a pictorial sketch of a haunched tenon constructed from a piece of timber 18 mm x 60 mm in cross-section.
(b) Calculate the sizes of the following parts of the haunched tenon sketched in question 4 (a).
(i) width of tenon;
(ii) thickness of tenon;
(iii) length of haunch.
(c) Use the answers obtained in question 4 (b) to dimension the haunched tenon.
Observation
Very few candidates attempted this question and only one candidate
performed well.
The solutions to the questions are stated as follow:
- Pictorial Sketch of a Haunched Tenon
(B)Calculations
(I) Width of tenon = 2/3 x width of timber
= 2/3 x 60 = 40 mm
(II) Thickness of tenon = 1/3 x thickness of timber
= 1/3 x 18 = 6 mm
(III) dimension the tenon width
- dimension the tenon thickness
- dimension the haunch length