A method of manufacture of printers and printheads formed of a number of modules (28) mounted on a chassis (30). The modules (28) and chassis (30) are formed with a number of alignment features (2,2a,2b,10,10a,10b) which engage with one another to form elastic interference couplings. By arranging a number n of such couplings for each module (28), the variance in positional error of each module (28) with respect to the chassis (30) can be made significantly less than the alignment error of the alignment features (2,2a,2b,10,10a,10b) themselves, by the process of Average Elastic Alignment. The elastic interference couplings can advantageously by made to form a sealed coupling for the supply of ink from the chassis (30) to each module (28).