Abstract: A clamp (10) for use in assembly of a microneedle device (100) has a flexible collet (14) projecting upwards from a base (12). The flexible collet (14) grips an adapter (106) of the microneedle device (100). A displaceable fixture (16), with two locating edges (18), (20), is displaceably mounted to base (12) so as to be displaceable between a raised position for positioning an adapter on the flexible collet and a lowered position in which locating edges (18), (20) abut surfaces of adapter (106) to achieve precise positioning of the adapter in two dimensions. An attachment surface (108) of the adapter (106) projects above locating edges (18), (20) of fixture (16) so as to be accessible for attachment of substrate (102).