Packaging conveyors and form-fill-seal machines rely on a 1008-5050 taper-lock bushing series, where bore spans 1/2 to 5 in, wrench torque ranges 55-3,100 in-lbs, and torque capacity tops out at 126,000 in-lbs at the 5050 size [S4].
Selection is driven by three variables: peak torque at the driven pulley, shaft diameter tolerance, and the hub geometry of the mounted sprocket, timing pulley, or coupling used in packaging machinery drivetrains [S1][S2].
Bushing Family and Mounting Method
The three families in industrial service are Taper Lock, QD (Quick Disconnect), and Double Split Taper, each differing in flange and split geometry that dictates how radial clamping force is generated on the shaft [S1]. Taper-lock bushings are the dominant choice on packaging lines because their flanged, split-tapered bore allows installation and removal without keys or set screws, which speeds changeover on multi-format packaging lines [S3][S4]. QD bushings use a heavier flange and higher screw count, typically specified for larger conveyors or outboard drives where frequent removal is not expected, while Double Split Taper is reserved for very large bores where a single taper would generate excessive hoop stress [S1].
For OEM procurement the Taper Lock family dominates; the 1008-5050 series covers 16 stock bore ranges from 1/2 in through 5 in, with an optional shallow keyway on the 1008 and 1108 sizes for soft shafts [S4].
Size-Series Specs That Drive Selection
The 1008-5050 metric/inch series maps shaft bore to a defined bolt circle, screw size, and tightening torque, which is the practical limit chart engineers work from at the panel saw [S4]. For the small end, 1008 takes a 1/2 in max bore with 1/4 in UNC screws torqued to 55 in-lbs and a torque capacity of 1,200 in-lbs; 1108 reaches 1-1/8 in with the same 55 in-lbs wrench torque but 1,300 in-lbs capacity. Mid-series 2012 covers 7/8-2 in bores at 280 in-lbs wrench torque and 7,150 in-lbs capacity, while 2517 jumps to 1-1/4-2-1/2 in at 430 in-lbs / 11,600 in-lbs capacity. The 3020-3030 pair holds a 4-1/4 in bolt circle, 5/8 in screws, 800 in-lbs wrench torque, and 24,000 in-lbs capacity. Heavy end 3535, 4040, 4545, and 5050 climb through 1,000, 1,700, 2,450, and 3,100 in-lbs wrench torque, with 5050 reaching 126,000 in-lbs torque capacity on a 7 in bolt circle with 7/8 in screws [S4].
Wrench torque figures are vendor-published, not standard-mandated, so the same bushing number from different manufacturers can carry different installation torque values, which is why OEM drawings usually pin a brand family such as TAPER-LOCK alongside the number [S5].
Matching Bushing Number to Packaging Drive Load
The selection rule of thumb is to size the bushing number so the rated torque capacity exceeds the peak transmitted torque by at least 25-50%, with the upper end reserved for drives with frequent start-stop cycles such as servo-driven film feed on vacuum packaging machines [S4][S7]. For light V-belt or timing-belt conveyors driving small timing pulleys, 1008-1210 covers most applications; mid-frame form-fill-seal heads and case erectors typically fall in the 1610-2517 band; large shrink tunnels and palletising conveyors step up to 3020-3535; the 4040-5050 range is reserved for main drive shafts on heavy cartoning or wrapping machinery [S4][S5].
Where stainless or food-grade corrosion resistance is required, suppliers such as Linn Gear mark stainless-steel variants with an "SS" suffix on the catalog number, allowing the same bore geometry to drop into washdown zones on food packaging lines [S5].
Comparison of the Three Bushing Types on Packaging Decision Criteria
On a like-for-like bore, the practical differences for packaging engineers are summarised below, drawn from the three families documented in industry guides [S1].
Type. Installation / removal speed. Torque capacity per size. Typical packaging use case. Taper Lock: Fast (screws only, no key): mid-to-high (1,200-126,000 in-lbs across 1008-5050): default on conveyors, timing pulleys, form-fill-seal packaging machinery [S3][S4]. QD (Quick Disconnect): Moderate (heavier flange, more screws): high, but fewer size steps: large outboard drives, infrequent removal [S1]. Double Split Taper: Slower (two-piece split, more fasteners): very high, large bores only: heavy main drive shafts above the 5050 envelope [S1].
For most packaging-cell changeover, the deciding factor is changeover time, and the Taper Lock's screw-only extraction, with no keyway to dress, is the reason it dominates conveyor and timing-pulley hubs in this sector [S3][S7].
Material, Bore, and Keyway Considerations
Standard Taper Lock bushings are machined from medium-carbon steel or high-grade cast iron, with stainless variants available for washdown; the 1008 and 1108 sizes offer both a standard and a shallow keyway to suit soft shaft materials where a full-depth key would risk stress concentration [S4][S5]. Bore options cover 1/2 to 5 in within the standard series, and custom bore and keyway sizes are quoted on request for non-standard shafts, with locking set screws included as standard on most supplier lines [S4][S5].
For hygienic packaging zones, electropolished stainless variants of the same 1008-2517 numbers are used without changing the host pulley or coupling, which simplifies spare-parts holding across a multi-line facility [S5].
Standards, Tolerances, and Common Pitfalls
There is no single ISO or ANSI standard that fixes every taper-lock dimension; the family is a de-facto industry standard, with bore, bolt circle, and screw sizes reproduced across manufacturers under their own trademarks (TAPER-LOCK, QD, Double Split) [S5][S6]. Hub diameter is published as reference only, and severe-duty applications may require a larger hub, while lightly loaded drives may accept a slightly smaller one, which is why suppliers always publish an "inquire about specific application" caveat next to the size table [S5].
Common failure modes on packaging lines are loose screws from under-torque, misaligned hubs that load the bushing flange in bending rather than torsion, and use of the wrong bushing number for a re-rated motor after a retrofit, all of which show up as fretting corrosion on the shaft within the first 1,000-3,000 operating hours [S3][S7].
Procurement Checklist for Packaging OEMs
Specify bushing family (Taper Lock / QD / Double Split) and the four-digit number (e.g. 2012) on the engineering drawing, together with required bore, keyway, and material suffix (S for steel, SS for stainless) [S4][S5]. Pin the installation torque value in the work instruction so maintenance teams do not under- or over-torque the screws, and confirm the bolt circle on the mating pulley or taper bush hub matches the bushing before sign-off [S4][S7]. Finally, order at least one spare bushing per active size per line, since a worn bushing typically indicates the host shaft has also been checked and both should be replaced together [S3].
Looking ahead, watch the 2026 revisions of supplier catalogs for any change in the 5050 torque-capacity rating, and confirm with each taper bush supplier whether their 2026 stock 1008-2517 parts are still rated to the figures tabulated above, since bushing numbers are stable but per-series torque ratings do move between catalog editions [S4][S5].
See also our earlier report, POM material selection for construction: grades, limits, indoor fit-out.