Key Terminology Key Terminology ayoung802 (Mechanical) (OP) 11 Nov 09 18:50 I've been asked to calculate the cracking area of a shaft key. What is the cracking area?I know the shear area is the length of the key times the width.Thanks in advance RE: Key Terminology dicer (Automotive) 14 Nov 09 02:51 I'd ask for the sample that cracked. RE: Key Terminology ayoung802 (Mechanical) (OP) 16 Nov 09 10:21 The cracking area is one of the two failure modes of a key. So I'm trying to calculate the area, asking for the sample isn't so easy when we don't have one.I eventually came across a website that I was confident enough with to proceed. The cracking area is the length of the key times the height of the key engadged with the shaft. Subtract out any fillets or radii that prevents the shaft and key from contacting.