Profile: Helical Lap & Mfg. Co. is a lap and manufacturing company. Lapping is a two motion (rotation and reciprocation), low pressure, abrasive machining process which utilizes a lapping tool along with an abrasive in a compound form. The lapping process results in stock removal ranging from a few thousandths of an inch to several millionths of an inch. Any desired surface finish can be achieved. We provide external lapping and internal lapping. External lapping should be shorter than the length of the part being lapped. When lapping a cylindrical part with lands, the external lap should be long enough to span as many lands as possible to prevent rolling edges.