Abstract: A clamp for tightening heating coils around a cylindrical object being heated has a split tubular housing with straps extending from each housing edge and forming loops pulled together by forces exerted from a pair of wedging elements with conical surfaces. The wedging elements have a cylindrical portion journalled in loops connected to one housing edge and a conical inner portion on which a strap connected to the other housing edge is mounted. Movement of the wedging elements axially with respect to one another changes the effective diameter of the conical portions engaging the strap. This causes the housing edges to be pulled together. Movement of the wedging elements with respect to one another is provided by securing one element to a mounting pin and providing a threaded bore through the other element, the element with the bore being restrained from rotation. When threads on the pin engage the threaded bore, the elements are pulled together.