A clamp assembly is disclosed for detachably retaining a curved laying pipe along the correspondingly curved edge of an auger support plate in a rolling mill laying head. The clamp assembly comprises a boss fixed to and projecting from the curved edge of the support plate. The boss has a first opening extending therethrough and an exterior support surface. A generally U-shaped clamp has a bridging web joining mutually spaced cheeks with second openings extending therethrough. The cheeks are configured and arranged to straddle the boss with their second openings in alignment with the first opening in the boss, and with the bridging web coacting with the exterior support surface of the boss to confine a segment of the laying pipe therebetween. A pin extends in an inserted position through the aligned first and second openings in the boss and the cheeks.