The Stockpile · Pile 02 — The Parts
CEMA B–F idlers in stock — steel and composite, matched to the load.
Douglas Manufacturing idlers in most common belt sizes — CEMA B, C and D — plus Enduride composite idlers, MSHA approved across CEMA C, D, E and F, including the One-Man Idler line and MSHA-recommended safety netting. Troughing, return, impact and self-aligning styles; garland sets and impact beds for load zones.
CEMA ratings (B through F) set the bearing, shaft and shell an idler is built around — roughly, light plant duty up through the heaviest mining and port service. Matching class to load matters more than brand: an underclassed idler is a scheduled failure, an overclassed one wasted money. Send us belt width, material density and lump size and the class picks itself.
A stopped roll under a moving belt is a friction heater and a belt-wear machine. Listen on the weekly walkdown: screeching today is seized this month — and rolls are cheap compared to belts.
| Class | Typical service | Common roll diameters |
|---|---|---|
| CEMA B | Light duty — package and light plant conveyors | 4″–5″ |
| CEMA C | Medium duty — aggregate, general industry | 4″–6″ |
| CEMA D | Medium-heavy — higher tonnage, wider belts | 5″–6″ |
| CEMA E | Heavy duty — mining, high tonnage | 6″–7″ |
| CEMA F | Heaviest — large mining and port service | 7″+ |
The class sets bearing, shaft and shell together — matching class to load matters more than brand. Send belt width, material density, lump size and belt speed and the class picks itself.
| Symptom | Likely cause | Fix |
|---|---|---|
| Screeching or stopped roll | Bearing failing — roll is now a belt-wear machine | Replace the roll now; rolls are cheap, belts are not |
| Belt mistracks at one frame | Frame out of square, or buildup on that roll | Square the frame; clean the roll; check nearby loading |
| Shells wearing through at load zone | Impact exceeding the idler class | Impact bed or garland set; verify CEMA class |
| Buildup caking return rolls | Carryback from an under-performing cleaner | Fix the cleaner; fit rubber-disc returns |
Frame tag photo plus belt width and trough angle usually nails it. No tag? Measure roll diameter, roll length and frame drop — we’ll match it.
Composite wins on weight, corrosion and maintenance labor; steel remains fine in dry, heavy standard duty. On high or awkward runs, the one-person roll change usually decides it.
Yes — impact beds and garland sets for load zones, where sealing and belt life are won or lost.
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