Introduction
Built to drive the fast-paced paving season: high-torque power transmission components for asphalt plants, batch mixers, road machinery & track-driven equipment.
Paving equipment lives in a brutal middle ground: 300°F–400°F hot mix asphalt radiating heat onto drive components, liquid asphalt binder gluing abrasive fines into every tooth root, and silica sand, crushed granite, and RAP (Reclaimed Asphalt Pavement) grinding away at gear flanks around the clock. Cogmatic manufactures flame-machined sprockets, ring gears, and pinions engineered specifically for these conditions — with an ultra-hard wear surface, a shock-absorbing core, and segmented designs that get you back to making mix in a single shift.
From Asphalt Plant to Paver: Components We Manufacture
Cogmatic supplies drive components across the full paving chain — from the plant that makes the mix to the machine that lays it down.
Sprockets
- Trommels & rotary screens
- Drag slat conveyors
- Drying drums & rotary dryers
- Bucket elevators
- Motor graders & road graders
- Asphalt pavers & material transfer vehicles
- Cold planers & reclaimers
- Slipform pavers
- Concrete placers & spreaders
- Undercarriage crawlers
Gears
- Tilt mixers
- Horizontal (reversing) mixers
- Rotary drum mixer & dryer girth gears
- Drive pinions for all of the above
When the Slat Stops, the Whole Fleet Stops
An asphalt plant never fails alone. When a drag slat conveyor jams at the top of a 100-foot surge silo, or a drum mixer ring gear binds mid-run, the failure cascades instantly: haul trucks queue up with nowhere to dump, pavers and rollers sit idle on the roadbed, and the mix already in the system starts hardening where it stands.
The math is unforgiving. Modern plants produce 200–600 tons of mix per hour, and with hot mix selling in the range of $75–$125 per ton, every hour offline halts $15,000–$40,000 or more in production alone — before counting idled paving crews, stranded trucking, wasted mix hardening in the system, and missed DOT lane-closure windows.
The same cascade runs downstream. A slipform paver with a failed track drive sprocket stops a continuous concrete pour mid-slab. A grader down for a circle drive or tandem chain stops the subgrade work that everything behind it depends on.
That is the problem Cogmatic components are built to solve: not just lasting longer in heat and abrasion, but being replaceable fast when the time comes.
Heat, RAP and Startup Torque Require Dual-Property Steel
Paving components fail in two opposite ways: teeth that are too soft wear away under silica and RAP abrasion; teeth that are too hard shatter under the massive startup torque of a fully loaded conveyor, a batch mixer starting against a dead-weight load, or a track drive breaking a machine loose from a cold, sticky mat.
Cogmatic solves both at once with dual-property metallurgy:
- Domestic high-carbon U.S. plate steel — no castings, no imported mystery metallurgy.
- Differential induction heat treating hardens tooth flanks up to 60–65 Rockwell-C, shrugging off the grinding action of crushed granite, gravel, silica sand, cement powder, and RAP fines.
- A ductile, tough core remains beneath the hardened case, acting as a dynamic shock absorber when motors start high-inertia loads — cold mix in a slat conveyor, a full drum of heavy-slump concrete, a loaded trommel breaking free of a static bed of aggregate, or a milling drum striking a manhole cover.
The result is a tooth that wears like a file but takes hits like a spring.
Precision Tooth Profiles for Hot-Mix Drives
Cold-machining a 10-foot drum ring gear or a 6-foot silo sprocket is slow and expensive. Standard flame cutting is cheap but leaves jagged, carbon-depleted tooth edges that wear out fast and run rough.
Cogmatic’s proprietary oxy-propane flame machining cuts exact tooth geometry in a single pass:
- 125 microinch surface finish on tooth profiles — smooth enough that sticky asphalt binder and fine dust don’t find a foothold in the root diameter.
- Machining tolerances within ±0.005 in on mounting surfaces, holding pitch accuracy and concentricity even across very large diameters.
- Lower production cost than conventional machining at large sizes — without the wear penalty of rough flame-cut teeth.
On a long, elevated drag conveyor, that accuracy keeps the chain tracking true. On a rotary drum or trommel, it is what eliminates the backlash chatter that destroys pinions and gearboxes. On a track undercarriage, it is what keeps pitch matched to the chain so the machine doesn’t throw a track on grade.
Paving Component Capabilities & Specifications
|
Parameter |
Capability Range |
Why It Matters in Paving & Road Construction |
|---|---|---|
|
Outer Diameter |
12 in to 18 ft |
Scales from compact paver, placer, and slipform track drives up to massive asphalt drum mixer ring gears, trommel girth drives, and surge silo head sprockets. |
|
Face Width |
Up to 5 in |
Spreads high drive torque across wider tooth flanks, preventing tooth peening under heavy startup loads with cold HMA, heavy-slump concrete, or a loaded trommel. |
|
Chain Pitch |
1 in and larger |
Matches heavy engineered chains including 4″ and 6″ pitch offset roller chains (ANSI #160, #200, WDH, custom drag slat profiles), bucket elevator chain, grader tandem drive chain, and undercarriage track chain. |
|
Gear Pitch |
¾ to 3 DP / 8.5 to 30 Module |
Coarse pitch means thick, unbreakable teeth built to turn high-tonnage rotary dryers, trommels, tilt mixers, and horizontal mixers without shearing. |
|
Case Hardness |
Up to 60–65 Rockwell-C |
Resists severe gouging and slurry abrasion from crushed granite, gravel, RAP fines, silica sand, cement powder, and subgrade soils. |
|
Machining Tolerance |
Within ±0.005 in |
Keeps long elevated drag conveyors and bucket elevators tracking true, and eliminates gear binding caused by drum shell thermal expansion. |
|
Segmented & Split Builds |
2-piece and 4-piece |
Lets millwrights replace drive sprockets atop silos, girth gears around drums and trommels, and circle segments on graders without pulling shafts, bearings, or chains. |
Core Paving & Road Construction Applications
Sprocket-Driven Equipment
Drag Slat Conveyors & Transfer Systems
Drag slat conveyors pull hundreds of tons of hot mix asphalt per hour up 45-degree inclines to surge silos, with head shafts running under constant 300°F–400°F thermal radiation, liquid binder, and aggregate dust. On standard cast or low-carbon sprockets, abrasive fines trapped in bitumen rapidly wear the tooth beds — and as the profile degrades, the 4″ or 6″ pitch offset drag chain slips, skips teeth, and eventually jams catastrophically at the top of the silo.
Cogmatic flame-machines tooth pockets to exact pitch clearance with a 125 microinch finish, so sticky asphalt and fines can’t pack into the root diameter. Deep induction hardening (up to 60–65 Rc) on the flanks resists aggregate-slurry abrasion, while the ductile core carries continuous high-torque drag loads on engineered chain sprockets.
Trommels & Rotary Screens
Trommels separate and classify aggregate, RAP, compost, and recycled material by tumbling it through a rotating drum screen — and many are driven by a girth chain wrapped around the drum shell engaging a drive sprocket, or by a chain-and-sprocket reduction off the drive head. The load is the worst kind: high starting inertia against a static bed of material, then continuous rotation in a constant fog of abrasive fines that settle directly into the chain and sprocket teeth.
Cogmatic builds large-diameter drive and girth sprockets with hardened flanks that survive that fines-laden environment, and a ductile core that absorbs the shock of breaking a loaded drum free on every startup. Split and segmented builds mean the girth sprocket comes off the drum shell in place — no drum removal, no cutting.
Drying Drums & Rotary Dryers
Rotary drying drums run continuously at 300°F–400°F, driving off moisture from aggregate before it meets the binder, with flighting tumbling material through the burner flame. Whether your drum turns on a girth chain and drive sprocket or a ring gear and pinion, the drive components live in the hardest place on the plant: thermal expansion of the drum shell walking the drive out of alignment, radiant heat soaking into the drive train, and airborne fines packing every tooth root.
Cogmatic manufactures both — flame-machined girth sprockets for chain-driven drums and coarse-pitch ring gears and pinions for gear-driven drums — held to ±0.005 in concentricity across diameters up to 18 ft. The precision profile keeps engagement smooth as the shell grows and shrinks through a production day, and the split design installs directly on the drum shell without a trunnion teardown.
Bucket Elevators
Hot elevators lift dried aggregate from the drum to the screen deck and hot bins, running chain-and-bucket at full load, continuously, in heat and dust. Head shaft sprockets carry the entire suspended weight of the chain, buckets, and material — and when a worn sprocket lets the chain climb the teeth, the result is a shed bucket, a jammed boot, and a plant down at the worst possible moment.
Cogmatic supplies head, boot, and take-up sprockets machined to exact chain pitch, with the hardened flank depth to hold that pitch through seasons of loaded running instead of hooking over in a single one.
Motor Graders & Road Graders
Motor graders carry two very different wear points, and Cogmatic builds for both. Tandem drive sprockets and chain inside the tandem housings transmit every bit of drive torque to the rear wheels, submerged in oil but loaded hard on grade and shock-loaded whenever the blade catches. Circle drive teeth — the toothed ring that rotates the drawbar and moldboard through a drive pinion — carry the entire cutting reaction of the blade, and are among the highest-wear components on the machine.
Both are exactly what flame machining is good at: large diameter, coarse pitch, thick teeth that need a hard face over a tough core. Cogmatic builds tandem drive sprockets to your existing chain pitch and circle drive gears and segments to your existing bolt pattern — the same approach applied across construction and earth-moving equipment.
Asphalt Pavers & Material Transfer Vehicles (MTVs)
Material transfer vehicles and highway-class pavers handle hot mix right on the roadbed, where hopper drag slats and crawler undercarriages run in heat, tack coat overspray, and loose aggregate base. Asphalt tack and crushed stone pack into sprocket root diameters, artificially increasing chain tension — leading to pitch elongation, tooth hooking, and track derailment.
Cogmatic builds custom track and conveyor drive sprockets with machined asphalt-relief notches in the root diameter. As each bushing or link engages, squeezed debris is pushed outward through the relief ports instead of compacting under the chain — keeping the chain seated and pitch alignment true.
Cold Planers, Milling Machines & Reclaimers
Milling machines cut existing asphalt and concrete at high speed, moving reclaimed material up fast elevation conveyors. The signature failure mode here is impact: violent torque spikes when cutter drums strike manhole covers, rebar, or concrete joints, transmitted straight into conveyor drives, track drives, and hydraulic motors.
Cogmatic’s smooth single-pass tooth profiles keep the chain continuously engaged without vibration, while the ductile steel core cushions impact spikes before they reach the drive motors.
Slipform Pavers
Slipform pavers extrude curb, gutter, barrier, and mainline slab in a single continuous pass — and continuity is the whole point. The machine has to crawl at a dead-steady creep while carrying the weight of a full mold and fresh concrete, often on a soft or freshly graded track line. Any inconsistency in the track drive shows up in the finished slab as a wave or a mismatch.
Cogmatic builds track drive sprockets matched precisely to undercarriage chain pitch, hardened to hold that pitch under low-speed, high-torque creeping loads, so the drive stays smooth and the pour stays true. Split builds let a crew swap a sprocket on the machine rather than pulling the final drive.
Concrete Placers & Spreaders
Placers run ahead of the paver, receiving concrete and distributing it to width, riding on long crawler tracks with heavy triple-grouser shoes and feeding through wide folding conveyors and twin augers — every one of those systems a drive point running in wet concrete and grit.
Wet cement slurry is the single most effective grinding compound on a paving job, and it goes exactly where the track chain meets the sprocket. Cogmatic’s Rc60–65 hardened flanks are specified for precisely that abrasion, and conveyor and auger drive sprockets are built to your existing chain and shaft.
Undercarriage Crawlers
Every tracked machine on the job — pavers, MTVs, cold planers, slipform pavers, placers, trimmers — ultimately depends on one wear part: the track drive sprocket. As it wears, tooth profile hooks, effective pitch drifts away from the chain, and the machine starts throwing tracks, chewing bushings, and burning through undercarriage sets far ahead of schedule.
Cogmatic manufactures crawler sprockets and segment groups from domestic plate with a deep hardened case over a ductile core — hard enough to hold profile against soil and aggregate abrasion, tough enough to survive the impact of tracking over broken concrete and milled surfaces. Segmented builds bolt on in the field without splitting the final drive.
Gear-Driven Equipment
Tilt Mixers
Central mix tilt drum mixers start heavy, dead-weight loads at full batch capacity, then rotate and tilt the entire loaded drum to discharge — a duty cycle that combines maximum starting torque with a changing load vector, all while the drive is coated in the most abrasive grinding compound on any jobsite: fine cement powder mixed with wet sand.
Cogmatic’s dual-property metallurgy answers both failure modes at once: an ultra-hard Rc60+ case shrugs off the cement/sand abrasion, while the ductile high-carbon core absorbs the shock of full-load startups and repeated tilting cycles. Coarse-pitch teeth — ¾ to 3 DP — are sized thick enough that they don’t shear when the drum starts against a full batch. In one stationary concrete mixing plant, Cogmatic’s engineers traced chronic early wear to a subtle bump near the pitch line of a long-established tooth form — and simply smoothing that transition delivered longer life and quieter operation.
Horizontal & Twin-Shaft Mixers
Horizontal reversing and twin-shaft mixers drive paddle shafts directly through the batch, meaning the gears never get a soft start — every cycle begins under full load, and reversing duty adds a torque reversal on top of that. Backlash in a worn open gear set becomes a hammer blow on every direction change, and it accelerates until something breaks.
Cogmatic’s ±0.005 in machining tolerance keeps backlash tight from day one, the 125 microinch tooth finish resists the cement paste that packs into rough-cut roots, and the hardened-case/ductile-core structure carries reversing shock without cracking teeth.
Rotary Drum Mixers & Kiln Girth Gears
Rotary drums 8 to 12+ feet in diameter tumble aggregate, RAP, and liquid binder continuously, driven by perimeter ring gears (girth gears) and pinions under extreme dynamic load and thermal expansion. Heat distorts the drum, throws standard ring gears out of alignment, and the resulting backlash chatter pits teeth and destroys drive gearheads. Worse, replacing a continuous 10-foot ring gear traditionally means cutting the drum shell or dismantling the trunnions.
Cogmatic manufactures large-diameter flame-machined ring gears and pinions up to 18 ft OD, holding ±0.005 in concentricity, with coarse-pitch teeth sized for low-speed, high-torque rotation. Critically, split and 4-piece segmented rings install directly on the drum shell — no trunnion teardown, no cutting steel. Cogmatic has built two 18-foot segmented gears at 7,000 lb each, bolted together in the field and running without fault since 2011.
Service the Drive Without Dismantling the Plant or Machine
Replacing a solid head sprocket at the top of a 100-foot drag conveyor, a girth drive around a trommel, or a continuous ring gear around a drum mixer normally means 2 to 4 days of total shutdown: crane rental, shaft and bearing removal, chain teardown — all while the paving schedule burns.
Cogmatic builds every large component as a solid ring first — flame-machined and heat-treated as one piece for perfect geometry — then match-marks and splits it into 2-piece or 4-piece precision-pinned segments.
|
Configuration |
Best For |
Field Advantage |
|---|---|---|
|
Solid ring |
New builds, accessible shafts |
Maximum simplicity |
|
2-piece split |
Silo head sprockets, conveyor drives, bucket elevator head shafts, track drive sprockets |
Swap on the shaft — no bearing or chain removal |
|
4-piece segmented |
Drum and trommel girth gears, grader circles, largest diameters |
Install around the drum shell or circle in place |
Your millwrights bolt the segments around the existing shaft or drum, and the plant is making mix again the same day. Against $10,000–$25,000 per hour of downtime, the split design typically pays for itself the first time it’s used.
Documented Steel Quality for DOT-Focused Paving Work
Every Cogmatic component is produced from domestic U.S. plate steel with full material traceability — mill certs, hardness verification, and dimensional inspection records available with every order. When a DOT project or plant insurance audit asks where your drive components came from, the paperwork exists — and domestic sourcing also keeps tariff exposure off your parts pricing.
From Worn Paving Part to Drop-In Replacement
Most paving component replacements start with a worn part, not a drawing. Send Cogmatic the worn sprocket or gear — or even dimensions taken in the field — and their engineering team reverse-engineers the original geometry, corrects any inherited design weaknesses, and builds to fit your existing chain, shaft, and bolt pattern. Plant and machine OEM part numbers from Astec, Gencor, Maxam, CWMF, Stansteel, CON-E-CO, and others are familiar territory.
Longer Service Life, Fewer Teardowns and Less Scrap
Longer-wearing components mean fewer replacements, less scrap, and less freight. Domestic sourcing shortens the supply chain, and split designs eliminate the crane mobilizations and multi-day teardowns that inflate the true cost — and carbon footprint — of every conventional replacement. In an industry that already leads on recycling through RAP, drive components that last longer and install cleaner fit the same story.
Built to Keep Paving Crews Moving
- Sprockets, ring gears & pinions from 12 in to 18 ft OD
- Tooth flanks induction-hardened to 60–65 Rockwell-C over a ductile shock-absorbing core
- Flame-machined accuracy: ±0.005 in tolerance, 125 microinch finish
- 4″ and 6″ pitch drag slat chain sprockets and coarse-DP drum, trommel, and mixer gears
- Bucket elevator head, boot, and take-up sprockets
- Grader tandem drive sprockets and circle drive gears
- Track drive sprockets and segment groups for pavers, MTVs, cold planers, slipform pavers, and placers
- Asphalt-relief root notches for paver and MTV sprockets
- 2-piece and 4-piece split designs — replace in a shift, not a shutdown