Can PairGears manufacture custom double-helical gears?

Question

Accepted Answer

Can PairGears manufacture custom double-helical gears?

Yes. PairGears lists custom double-helical and herringbone gear services. Send the complete gear and mating-part drawings for manufacturing review, including tooth geometry, material, heat treatment and inspection requirements. Confirm whether the design has a center relief gap or continuous V-shaped teeth; the required manufacturing route and acceptance criteria depend on that distinction.

Identify the exact tooth arrangement

Double-helical designs combine left-hand and right-hand teeth. A center relief gap separates the two halves in many designs; herringbone commonly describes teeth meeting in a continuous V. Terminology varies, so the drawing should show the intended arrangement explicitly.

The PairGears comparison of helical gear types explains these differences. Opposing tooth forces can balance axial thrust under balanced loading, but alignment, load sharing and bearing requirements still need an engineering check.

Historic gear assembly with opposing helical tooth directions forming a V — A historical herringbone arrangement illustrates opposing tooth directions; this is not a PairGears product sample. Photo: Parchaco / Wikimedia Commons, CC0.

Provide a complete manufacturing specification

Include tooth count, module and its normal or transverse convention, pressure angle, helix angle, both tooth hands, face widths and center-gap dimensions. Specify the bore or shaft connection, datums, material, heat treatment, tolerances and inspection standard. Supply mating-gear geometry and the intended operating center distance.

For example, a replacement request describing only “a double-helical gear with the same outside diameter” leaves tooth compatibility and mounting unresolved. Add the original drawing revision, application speed and torque, and photographs or measurements of the existing assembly. PairGears describes custom options in its custom helical gear service guide.

Two people reviewing a drawing beside gear-manufacturing equipment — Review the drawing and application together before confirming the manufacturing route. Image: PairGears.

Agree how the two halves will be checked

Ask the supplier to confirm machining access, the relative tooth alignment between halves, required finishing operations and the inspection plan. A narrow gap or continuous V may constrain tool access differently from a separated arrangement.

Agree the dimensional report and any paired contact or running checks before ordering. The available process, achievable tolerances, price and delivery schedule must be confirmed for the submitted design; a general service listing does not establish those values for every gear.