Taper bushing hubs let a stock jaw coupling accept any of a wide range of bored shaft diameters by mounting a standard taper-lock bushing into a half hub that has been pre-machined with a matching tapered bore [S4][S5]. The arrangement is widespread in Australian and North American industrial distribution, with size-38 H hubs shipped with pilot bore or 1108 taper-lock options in cast iron, aluminium, or steel [S4].
Price points on these finished assemblies cluster tightly across global e-commerce channels: an Applied Industrial 10R jaw coupling hub with a 1210 taper bushing lists at USD 104.68 each (with a MAC reference of USD 282.58 per hub) [S1], while the L100/1108 half-hub-taper-lock variant on AIMS Industrial lists at AUD 51.66 in October 2026 [S5]. Kop-Flex (Regal Rexnord) supplies a size-90 elastomeric hub in the EE/ES/SS family that pairs with a 3535 taper-lock bushing for heavy industrial service [S2].
What a taper bushing jaw-coupling hub actually is
A taper bushing jaw-coupling hub is a two-piece sub-assembly: a standard curved-jaw (L, H, or N-style) half hub with a tapered bore, plus a matching taper-lock bushing (commonly 1108, 1210, 1610, 2012, or 3535) that grips the drive shaft through a progressive full-length taper, not just a face taper [S6]. This construction gives a tighter concentric fit on the shaft than a QD bushing, which only contacts along the face [S6].
The hub body itself is normally a cast iron or steel blank, with aluminium offered for low-inertia or corrosion-light duties; pilot bore versions are available when the user will finish-machine the bore to a special shaft size in their own shop [S4]. For taper-lock fitment the receiving bore must be drilled and tapped, then the hub is mounted on the bushing so the bushing's axial screws draw it into the tapered seat, locking the assembly radially and axially against the shaft [S7].
Standard sizes and the bushing-to-hub interface
The taper-lock series covers a defined shaft range per bushing number. The 1108 bushing, the smallest commonly used on jaw couplings, accepts shafts from roughly 0.375 inch up to 1.000 inch (about 9.5 to 25.4 mm), while the 1210 extends to about 1.25 inch (31.75 mm) and the 3535 used in the Kop-Flex size-90 elastomeric hub covers the 3.5 inch (88.9 mm) range [S1][S2][S5].
Selection is governed by the jaw-coupling size, not the bushing alone: the L100 half-hub taper-lock variant carries the 1108 bushing on the L100 (Lovejoy-equivalent) jaw body [S5]; the size-38 curved-jaw H hub pairs with the 1108 bushing in the Bearing & Engineering product line [S4]; the Kop-Flex 90 EHUBTLX3535 mates a size-90 elastomeric body to a 3535 taper-lock [S2]. Because each jaw-coupling size has a defined hub face width and pilot diameter, users must match bushing OD and axial length to the hub's machined pocket, not the other way around [S8].
Materials, mounting, and maintenance behaviour
Cast iron is the default for general-purpose industrial drives because of its dampening and cost, while steel is preferred for high-torque or shock-loaded service such as the Kop-Flex size-90 elastomeric line, and aluminium is used where mass or corrosion resistance matters more than peak torque capacity [S2][S4]. All three materials are machined to accept the same taper-lock geometry, so interchangeability across castings is reliable as long as the pilot diameter and face width are within the coupling maker's tolerance stack.
Maintenance on a taper bushing jaw-coupling hub is essentially the maintenance of the bushing: loosen the cap screws, the bushing releases from the hub taper, and the elastomeric spider or curved-jaw element can be replaced without removing the hubs from either shaft [S2]. The Kop-Flex EE/ES/SS elastomeric series is explicitly marketed as a non-lubricated design intended to cut downtime on tough industrial applications, since the replaceable element and bushing interface are the only wear surfaces [S2]. For a practical inspection of a used bush before it goes back on a pulley or hub, reuse or scrap taper-bush inspection walks through the wear thresholds that determine if a bushing is still fit for a new hub mount.
Selection criteria: taper-lock vs QD vs pilot bore
Choose by shaft size, service environment, and how often the coupling will be removed. Taper-lock is the default for general industrial drives because the full-length progressive taper gives a tighter concentric grip on the shaft than QD's face-only contact [S6], and the bushing is reusable across many hub designs. QD bushings make sense where faster face-mounting is valued over radial concentricity, while pilot bore hubs are the right call only when the user has a boring machine and needs a non-standard bore not covered by the standard bushing catalogue [S4].
Comparison across the three options for a typical size-30 to size-90 jaw-coupling drive:
Taper-lock bushing: full-length progressive taper for tight concentric fit, common shaft coverage from 0.375 to 3.5 inches across the 1108 to 3535 series, reusable bushing, requires drilling and tapping the hub bore once [S6][S7]. QD bushing: face-mount, faster install, lower concentricity, reusable, common in USA light-industrial drives [S6]. Pilot bore hub: no bushing, finished to special bore in-house, lower unit cost but requires machining capacity and loses the quick-change benefit [S4]. For typical pump, fan, compressor, and conveyor drives where misalignment tolerance and shock-load absorption are needed, taper-lock hubs dominate the published catalogues [S5].
Application fit: where taper bushing jaw-coupling hubs actually ship
Taper bushing jaw-coupling hubs are most common in pump and motor drives, fan and compressor drives, conveyor systems, and general industrial machinery where two rotating shafts must be connected with torque transmission, misalignment tolerance, and shock-load protection [S5]. The size-38 curved-jaw H hub with 1108 taper-lock is a workhorse for small-frame motor-to-pump or motor-to-gearbox couplings in the 1 to 5 kW range, while the Kop-Flex 90 EHUBTLX3535 elastomeric hub targets the 50 to 200 kW range typical of larger pumps, fans, and process rolls [S2][S4][S5].
The eBay listing of a "4 TAPER BUSHING COUPLING HUB & WASHER 4-1/2 inch" kit, shipping three hubs and a single washer for use with taper bushings, sheaves, couplings, gear shafts, and other power-transmission hardware, illustrates how interchangeable the same bushing platform is across multiple driven elements on a single machine [S3]. SCI Couplings further confirms the bushing-platform philosophy by offering flex hubs and rigid hubs with either inboard or outboard mount bores for taper-lock bushings across its full coupling range [S8].
Limits, failure modes, and what to verify before ordering
Common failure modes traceable to the bushing-hub interface, not the spider or jaw element, are: hub taper bore worn oversize from running with loose cap screws, cap-screw threads stripped from over-torque, and shaft scoring from a bushing that was never fully seated [S7]. Practical Machinist threads confirm that as long as the taper angle is correct, the other tolerances are reasonably forgiving, but a hub that has been bell-mouthed by a slipped bushing will never concentrically grip a new bushing again and should be scrapped [S7].
Engineers should also verify three things before ordering: that the bushing number on the hub nameplate matches the bushing number being installed (size-90 elastomeric with a 3535 bushing, L100 half hub with 1108, etc.) [S2][S5]; that the hub face width and pilot diameter match the mating half hub so the spider or element is not over- or under-compressed; and that the maximum bore of the chosen bushing equals or exceeds the actual shaft diameter, with a small clearance for keyway. For more on locking-assembly concentricity trade-offs in adjacent power-transmission hardware, the taper-bush platform itself and the broader jaw coupling family are useful reference points when sizing a new hub-and-bushing sub-assembly.
Two trackable signals going forward: monitor whether Kop-Flex and other Regal Rexnord elastomeric lines extend the 3535 taper-lock platform into larger size-110 and size-130 elastomeric bodies, and watch distribution pricing on the 1210 bushing hubs at Applied Industrial, where list around USD 104.68 per hub currently undercuts the MAC reference of USD 282.58 and could indicate channel-level price compression through 2027 [S1][S2].
Component reference pages worth checking: industrial adhesive.