Painted-over plates, missing rivets, and rebuilds with blank covers are common on Indian plant floors. You do not need the original brand name to get a matched replacement — you need the mechanical interface recorded carefully in millimetres. If a plate still exists, photograph it first (see nameplate decoding), then measure everything below as a cross-check.
1. Centre distance (CD)
On a worm gearbox, centre distance is the perpendicular distance between the worm axis and the wheel axis. It is the size class of the unit (on Anand Gears cast iron worms this is the familiar CD designation). Measure from shaft centre to shaft centre with a height gauge or by calculating from housing faces if the unit is open. Record one value in mm — this dimension must match on the replacement.
2. Shaft diameters and lengths
- Input shaft diameter under the coupling or pulley (mm).
- Output shaft diameter(s) — both sides if double output.
- Usable shaft length from the housing face to the free end (mm).
- Keyway width, depth, and length if you can see them safely.
- Any steps, threads, or seal lands between housing and end.
3. Mounting footprint / hole PCD
- Foot-mounted: bolt-hole spacing length × width, hole diameter, and distance from mounting face to shaft centreline (mm).
- Flange-mounted: flange OD, spigot diameter, PCD of bolt circle, number of holes, hole size.
- Shaft-mounted / hollow: torque-arm hole positions if present.
Sketch the pattern on paper and photograph the sketch next to the unit.
4. Ratio (count turns)
Mark input and output with chalk or tape. Turn the input slowly and count how many full input revolutions produce one full output revolution. That count is approximately the reduction ratio. If a tachometer is available, ratio ≈ n_in / n_out at steady speed. When the unit can be opened safely, counting worm starts and wheel teeth is more definitive.
5. Overall dimensions
Record overall length, width, and height of the housing envelope in mm, including fan guards and motor adapters if they must clear nearby structure. Note which faces sit against foundations or guards.
6. Hollow bore size (if hollow output or hollow input)
- Bore diameter (mm) — measure with an internal micrometer or calipers at several points.
- Bore length / through-depth.
- Keyway or shrink-disk interface details if visible.
7. Mounting position / orientation
Photograph the side view. Note whether the worm is low (typical Under Driven), high (Over Driven), or a Top-Bottom / vertical arrangement. Wrong orientation can put oil where it does not belong even if shafts match.
Photo set to send with the measurements
- Full side view (orientation).
- Input end.
- Output end (both sides if needed).
- Foot or flange with scale or written dims in frame.
- Any remaining nameplate or stamped numbers.
What Anand Gears does with this data
We translate your millimetre sheet into a manufacturing drawing for a drop-in box or a rebuild path. Brand logos are irrelevant to the cut list. Start the quote from the contact form or the replacement service page.
Related: Gearbox Nameplate Decoding · Centre Distance Explained · Replacement & Repair · Contact