Abstract: A self aligning tube alignment bar for aligning and retaining a vertical series of boiler tubes in parallel. The tube alignment bar is comprised of two elongated parallel bar halves having a series of opposed recesses with interengaging protrusions therebetween to initially loosely confine the series of tubes respectively in a separated series. Thereafter the two halves are drawn together by bolts causing the two alignment bar halves to have their protrusions interengage and thereby guide the two halves together in clamping engagement such that ultimately the tubes are retained in a parallel series.