Abstract: A portable tube end cutting tool includes a tool support shaft with an alignment assembly at one end for insertion into the tube whose end surface is to be machined and a cutter head assembly mounted for rotation about the support shaft. The tool portion to be inserted into the tube space adjacent the tube end to be machined is compact and is adapted to be locked in accurate alignment by incremental rotation of the support shaft over small angular increments, and is particularly useful where the tube surfaces to be machined are located in confined or relatively inaccessible working places.