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Custom Couplings Machining & Pulleys

Custom couplings machining with bores held to H7 and pitch-diameter runout at 0.01 mm TIR. No MOQ, prototypes in 3–5 days, every drawing engineer-reviewed.

  • 0.01 mm

    TIR Runout to Bore

  • 3–5 days

    Prototype Delivery

  • H7

    Standard Bore Fit

CNC turning a custom coupling bore on a lathe spindle
ISO Certified ISO 9001, ISO 13485, AS9100D
Custom machined coupling and pulley on dark worktable

Custom Couplings Machining and Pulleys

DEK machines rigid and clamp shaft couplings, flange couplings, jaw and beam hubs, timing pulleys and V-belt sheaves, turned and milled from 6061 and 7075 aluminum, 1045 and 4140 steel, 303 stainless and Delrin.

Both families depend on bore-to-OD concentricity and bore fit: bores to H7 (H6 on request), critical dimensions to ±0.005 mm. They are catalogued with shafts and gears in our custom CNC machined parts range.

Types of Couplings & Pulleys We Machine

Couplings, coupling hubs, timing pulleys and sheaves, turned and milled from aluminum, steel, stainless and Delrin bar stock.

  • Machined clamp shaft coupling with keyway on worktable
    Rigid and Clamp Couplings
    Sleeve, set-screw and one- or two-piece clamp couplings for any shaft pair.
    H7 bore 7075-T6
  • Flange coupling half with bolt circle on worktable
    Flange Couplings
    Flange couplings and coupling halves with bolt circles and pilot fits.
    1045 steel CNC turning
  • Jaw spider coupling hub with keyway on worktable
    Jaw, Oldham and Disc Hubs
    Jaw (spider), Oldham and disc coupling hubs with keyways or clamp hubs.
    DIN 6885 Clamp hub
  • Helical beam coupling with slit flexure on worktable
    Beam Couplings
    Helical or parallel slits cut by wire EDM or slitting saw for flexure.
    Wire EDM 6061-T6
  • Aluminum GT2 timing pulley with flange on worktable
    Timing Pulley CNC Parts
    GT2, GT3, HTD 3M/5M/8M, T5/T10, MXL, XL and L profiles, flanged or not.
    ISO 5294 Hobbed teeth
  • Machined V-belt sheave with crowned groove on worktable
    V-Belt Custom Sheave
    A, B, SPZ, SPA sheaves, flat-belt crowned pulleys and idler pulleys.
    SPZ / SPA 4140

Coupling Materials, Processes & Tolerances

Materials, machining routes, tolerances and finishes for couplings and pulleys, all taken from production practice at DEK.

  • Materials for Couplings and Pulleys

    Aluminum for low inertia, steel for torque, stainless for washdown, Delrin for quiet drives.

    View Materials
    Material Why it is used
    Aluminum 6061-T6 Timing pulleys; low inertia
    Aluminum 7075-T6 Clamp force, fatigue life
    Mild steel 1045 Low-cost sheaves, rigid couplings
    Alloy steel 4140 High torque, hardened pulleys
    Stainless 303 / 316 Washdown, food, marine drives
    Delrin (POM) Quiet pulley, insulating couplings
  • Custom Pulleys Machining Processes

    Bores, ODs, hubs and grooves are cut in one chucking so the pitch diameter runs true to the bore.

    Get a Quote
    Process Used for
    CNC turning Bores, ODs, hubs, belt grooves
    Hobbing Timing pulley teeth
    CNC milling and drilling Clamp slots, jaws, set-screw holes
    Broaching or wire cutting Keyways
    Wire EDM Beam coupling slits
  • Shaft Coupling Machining Tolerances

    Concentricity and bore fit decide how a coupling or pulley runs; these are our typical values.

    • Bores H7 standard, H6 on request
    • Pitch-diameter runout 0.01 mm TIR
    • Keyways to DIN 6885 / ANSI B17.1
    Get a Quote
    Specification Typical capability
    Outside diameter 5 mm to 400 mm
    Bore 2–120 mm; H7, H6 on request
    Pitch-diameter runout to bore 0.01 mm TIR
    Bore-to-bore concentricity 0.01 mm
    Timing pulley tooth pitch ISO 5294; ±0.05 mm per 100 mm
    Keyways DIN 6885 / ANSI B17.1, P9 or JS9
    Set screws M3–M10 at 90° or 120°
    Surface finish Ra 0.8 µm; 0.4 µm grooves, bores
    Hardness 4140 28–32 HRC; grooves 50–55 HRC
  • Finishes for Couplings and Pulleys

    Finishes are applied only to couplings and pulleys DEK machines.

    View Finishes
    Finish Applied to
    Anodizing, clear or black Aluminum pulleys, couplings
    Hard-coat anodizing Belt contact surfaces, abrasion
    Black oxide Steel sheaves and couplings
    Zinc plating Steel sheaves and couplings
    Heat treatment Hardened parts, before grinding

Design Tips for Custom Couplings and Pulleys

Five drawing decisions that set how a coupling grips and how a pulley tracks its belt, before the first chip is cut.

  • Belt Profile and Tooth Count

    Specify profile and tooth count, not an approximate pitch diameter: the OD depends on the belt's pitch line differential.

  • Clamp Slit Wall

    Keep the clamp screw tangent to the bore and leave at least 1.5 mm of wall at the slit root; thinner walls crack when over-torqued.

  • Flanges on Timing Pulleys

    Add a flange on at least one side when shaft axes are not perfectly parallel; belts track off unflanged pulleys.

  • Bore Fit and Torque

    H7 with a set screw on a flat suits most drives; use a keyway or clamp hub above roughly 5 N·m or in reversing loads.

  • Groove Angle for a Custom Sheave

    State groove angle (34° or 38° by section and diameter) and groove pitch; both change with sheave diameter.

What to Call Out on Your Drawing

  • Bore Fit and Keyway

    State H7 or H6, plus keyway (DIN 6885 / ANSI B17.1, P9 or JS9) or set screw position, so the bore is turned to your shaft.

  • Belt or Groove Section

    Give GT2, HTD, T5 or MXL profile with tooth count, or A, B, SPZ or SPA groove section, so teeth are hobbed to ISO 5294.

  • Material and Hardness

    Name the alloy and any hardness: 4140 at 28–32 HRC, or induction-hardened groove faces at 50–55 HRC on request.

  • Quantity and Lead Time

    Add the quantity: there is no MOQ, and single sheaves or prototypes ship in 3–5 days after engineer review.

Applications & Industries

Belt-driven axes for robotics, conveyor and indexing drives for automation, motor couplings for new energy pumps and fans, gimbal drives for drones.

Why DEK for Shaft Coupling Machining

Hobbed teeth, one roof for every process and measured runout: why buyers send couplings and pulleys to DEK.

  • Hobbed, Not Milled Teeth

    Timing pulley teeth are cut with hobs, not a profile end mill, because a milled approximation of a GT2 tooth wears belts.

  • One Roof, Four Processes

    Turning, hobbing, milling and wire EDM run in-house, so a matched pulley pair and its clamp couplings ship as a set.

  • Runout Measured at FAI

    Bores are gauged and runout measured at first article inspection, against a 0.01 mm TIR pitch-diameter target.

  • No MOQ, Fast Prototypes

    No minimum order quantity; prototypes and single sheaves ship in 3–5 days, from one part to production runs.

Engineer Review on Every Drawing

Every coupling and pulley drawing is reviewed by an engineer before quoting, checking bore fit, belt profile and groove section, and quotes return within 6 hours.

Certified Quality on Every Drive Part

ISO 9001:2015, ISO 13485 and AS9100D certified, with bores gauged at FAI.

  • AS9100D and ISO 9001 certification logo
    AS9100D

    Aerospace Quality Management System

  • ISO 9001 certification logo
    ISO 9001:2015

    Quality Management Standard

  • ISO 13485 certification logo
    ISO 13485

    Medical Devices Quality Management

Couplings and Pulleys FAQ

Answers on bores, tooth counts, coupling types and small sheave runs.

Can you make a timing pulley with a custom bore or tooth count?
Yes. Timing pulleys are hobbed in GT2, GT3, HTD, T, MXL, XL and L profiles with any tooth count and a bore turned to your shaft, H7 with keyway or set screw, with no MOQ.
What is the difference between a rigid coupling and a clamp coupling?
A rigid coupling is a sleeve fixed to both shafts with set screws or keys; a clamp coupling grips the shafts by tightening a slit hub, which avoids marring the shaft and can be repositioned. Both are turned and milled to order.
Do you machine V-belt sheaves in small quantities?
Yes. Single sheaves and short runs in 1045, 4140, stainless or aluminum are turned to the correct groove angle and pitch for A, B, SPZ or SPA belts and ship in 3–5 days.

Get a Quote for Custom Couplings Machining

Send a drawing with bore fit, belt profile and tooth count or groove section, material and quantity. Engineer-reviewed quotes return within 6 hours.

  • No MOQ, from a single sheave
  • Prototypes ship in 3–5 days
  • Bores H7 standard, H6 on request
  • Runout 0.01 mm TIR, measured at FAI
Request an Aerospace Quote