Helical Lap & Manufacturing Company



Helical Lap & Manufacturing Company
121 Madison Avenue
Mount Clemens, MI 4804


Founded in 1958, Helical Lap is recognized as the premier producer of internal and external expanding cast iron cylindrical laps.  In 1979 we became part of the Engis Corporation group of companies. Our ability to serve customers worldwide is facilitated through the Engis network of companies and distribution.

Helical Lap’s range of standard and special I.D. and O.D. lapping tools are capable of producing mirror surface finishes with superior geometry to other finishing methods. There are many applications where Helical Cylindrical Lapping Tools can improve and correct imperfections in cylindrical geometry, for example:

  • Barrel-shaped bores
  • Improvement in straightness of I.D or O.D.
  • Bell-mouthed bores
  • Tapered I.D. or O.D.
  • Out of round conditions; both I.D. and O.D.

Cylindrical geometries that have been achieved with Helical Cylindrical Laps:

  • .000005″ (5 millionths) roundness
  • .000010″ (10 millionths) straightness
  • Surface finishes better than one microinch

Helical’s proprietary cast iron lapping tool formulation allows for expansion and contraction of the tool without breakage. Its uniform grain structure enhances the ability to consistently embed and hold abrasive particles in the lap. Tool hardness has been engineered to provide the optimal combination of fast stock removal and fine surface finishes. Higher stock removal amounts can be achieved by using coarse lapping pastes or honing tools such as the Engis Single-Pass Bore Finishing Tools prior to the lapping operation.

Helical Laps can be used for hand lapping but can also be mounted in lathes, mills, drill presses, and hand drills without elaborate setups

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