Gear Reducer Series Guide: HDR, CALM, SSHDR, SMR & More

Worm & Shaft-Mount Gear Reducer Series Guide

Eight reducer series, one selection question: what housing, what ratio, what mounting? This hub compares every series we stock so you can jump straight to the right collection - and the sizing guide covers the torque math.

Right-Angle Worm Reducers

Series Housing Ratios Pick It For
HDR Cast iron 5:1–100:1 The industrial default - 360+ configurations, C-face or solid input, hollow or solid output
CALM Aluminum 7.5:1–100:1 Weight-sensitive mounts, corrosion resistance without stainless cost
SSHDR Stainless steel 5:1–100:1 Food/pharma washdown - caustic chemicals, daily hose-down
KAN Aluminum, compact 4.5:1–120:1 Tight envelopes, light industrial
KHN Cast iron, compact 4.5:1–120:1 Compact with more thermal mass
WINL Cast iron 2:1–180:1 Widest ratio spread incl. low-ratio speed matching and deep double reduction
FHN Aluminum 5:1–110:1 Fractional-HP gearmotors and small machine drives

Shaft-Mount Reducers (Belt Primary)

For conveyor head shafts, the SMR series mounts directly on the driven shaft with a belt primary from a foot-mounted motor - 15:1 and 25:1 nominal, sized 2 through 10, and dimensionally interchangeable with the shaft-mount pattern made common by the Dodge TXT (see the TXT cross-reference). Variants: SCSMR packages the reducer with CEMA screw conveyor shafts and flanges for auger duty, and HYSMR takes hydraulic motor input for mobile equipment. Rebuild kits keep older units alive.

Replacing another brand? The SMR family crosses model-for-model from Dodge TXT, Browning SMTP, Hub City PT, and Cleveland Gear (see the published cross table or use the instant lookup tool), and WorldWide worm and helical lines replace Grove Gear, Falk, Boston Gear, Winsmith, Sterling Electric, Nord Clincher, and European R-series (SEW-type) units.

The Hardware Around the Reducer

Quick Selection Logic

  • Fixed machine, motor flange input → HDR (or CALM/SSHDR by environment).
  • Conveyor head shaft, belt drive → SMR with torque arm and bushing kit.
  • Screw conveyor → SCSMR with CEMA shaft.
  • Ratio above 100:1 → WINL double reduction or KAN/KHN to 120:1.
  • Fractional HP machine → FHN gearmotor.

Frequently Asked Questions

What is the difference between HDR, CALM, and SSHDR reducers?

Same worm gear concept, three housings: HDR is cast iron for general industrial duty, CALM is aluminum for lighter weight and better corrosion resistance, SSHDR is stainless steel for washdown and food-grade environments. Ratio coverage is similar (roughly 5:1 to 100:1), so environment picks the series.

How does a shaft-mount reducer differ from a foot-mounted worm gearbox?

A shaft-mount (SMR type) hangs directly on the driven shaft via a tapered bushing and reacts torque through an arm, taking motor input by V-belt - no aligned couplings or reducer foundation needed. Worm boxes foot-mount or flange-mount and couple directly to the motor.

Are SMR reducers interchangeable with Dodge TXT?

The SMR line follows the dimensional pattern the TXT made standard, size for size and ratio for ratio, so swaps are routine - verify size number, ratio, bushing bore, and torque arm arrangement before ordering. Our TXT cross-reference page walks through it.

Which reducer works for a washdown environment?

SSHDR stainless housings with food-grade lubricant handle daily caustic washdown; CALM aluminum suits milder wet duty. Pair with a washdown stainless motor for a complete corrosion-resistant drive.

Do you stock rebuild kits for older reducers?

Yes - SMR series rebuild kits (bearings, seals, gaskets) are listed by size, plus seal and hardware accessories for HDR, CALM, SSHDR, KAN/KHN, and FHN series.

Related Resources

Ratio, torque, mounting - we'll pick the series with you.

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