A scarf joint typically uses bevels on the surfaces at a slope of

• A. 1:10 or 1:12
• B. 2:1 or 3:2
• C. 1:20 or 1:30
• D. No bevels used

Answer: (A)

A scarf joint works by beveling the ends so the two pieces slide together and present a long, continuous bonding surface. Keeping the bevels at a shallow slope gives enough contact area for a strong adhesive bond without removing too much material or creating bulky geometry. Typical scarf bevels are in the 1:10 to 1:12 range, which provides a good balance between strength and practicality. Steeper bevels (like 2:1 or 3:2) would remove too much material and can weaken or misfit the joint, while extremely shallow ones (1:20 or 1:30) reduce the bonding area too much and weaken the joint. No bevels would defeat the purpose of a scarf joint by drastically limiting contact area.