A boiler tube clamp including a first portion having a first substantially U-shaped midsection with a first inner surface configured for receiving and pressing against one side of a boiler tube, a first hinge member arranged on one end of the first midsection, and a threaded bolt hingedly attached to the other end of the first midsection, and a second portion having a second substantially U-shaped midsection with a second inner surface configured for receiving and pressing against the other side of the boiler tube. The clamp further includes a second hinge member arranged on one end of the second midsection and hingedly connected to the first hinge member so that the first inner surface and the second inner surface close toward one another. An open slot is arranged at the other end of the second midsection configured for detachably receiving the threaded bolt. A lip extends radially out from an outer surface of the second midsection and arranged adjacent to an edge thereof. A jackscrew extends through the lip for adjusting the distance a boiler tube contained by the clamp extends into a boiler through a boiler header.