NETZSCH N.Mac Twin Shaft Grinder
Spare Parts for N.Mac Inline & Channel Twin Shaft Grinders
Product Summary
Genuine and compatible spare parts for the NETZSCH N.Mac® twin shaft grinder, used across Australia ahead of pumps in sewage pumping stations, wastewater inlet works, biogas substrate feed and food waste processing. Inline and channel versions share the same build (cutter discs and spacers stacked on hardened hexagonal shafts, held in a replaceable cutting cartridge with sealed bearing and mechanical seal cartridges), so tick what you need and we’ll match the parts to your nameplate (e.g. N.Mac 150I).
Spare Parts List
✓ Tick the parts you need. N.Mac cutters are matched to grinder size, version (inline or channel) and tooth count, so your nameplate model and serial number are all we need to get them right. Not sure which items? Add a photo of the nameplate and we’ll work out the parts for you.
| Select | Wear / Service Item | Function & when to replace |
|---|---|---|
| Common Service Kits | ||
| Cutter Discs (Cutting Blades) | The toothed cutting blades on each shaft, available with 3, 5, 7, 9 or 11 teeth (7 standard). Replace when edges are rounded or chipped and solids pass through ungrounded. | |
| Spacers | The spacers between each cutter disc that set the cutting gap with the opposite shaft. Replace with the cutters, as worn spacers let rags and solids slip through. | |
| Cutting Cartridge (Cutter Stack) | The complete cutting device, shafts with cutters and spacers, built as a cartridge for quick exchange. The fastest fix when the cutting stack is heavily worn or damaged. | |
| Mechanical Seal | Shaft seal with quench, housed in NETZSCH’s bearing and seal cartridge. Replace at the first sign of leakage or quench contamination. | |
| Bearing & Seal Cartridge | Sealed cartridge that protects the shaft bearings from the medium. Replace if bearings are rough or noisy, or if product has reached the bearings. | |
| O-Ring & Gasket Set | O-rings and gaskets for the housing, covers and cartridges, including the elastomer that seals the lower bearings and absorbs vibration. Renew at every cutter change. | |
| Other Core Parts | ||
| Hexagonal Shafts | The hardened hex shafts that carry and drive the cutter discs. Replace if bent after a hard-object strike or worn at the cutter seats. | |
| Gearbox / Reducer | Reduction gearbox (around 1:29) that delivers the low speed, high torque the cutters need. Replace or overhaul if noisy, leaking oil or slipping under load. | |
| Drive Motor | Energy-efficient drive motor from 2.2 to 4 kW across the range, matched to your size and supply. | |
| Cleaning Comb / Brush | Optional comb or brush that clears fibres and rags from between the cutters. Replace if worn or bent, or fit one if rags keep wrapping the stack. | |
| Reversing Control Unit | Optional controller that senses a jam and reverses rotation to clear it. Replace or repair if the grinder stops instead of auto-clearing. | |
| Housing / Frame | The inline housing with flanges, or the channel frame with lifting lugs. Replace if cracked or corroded. | |
| Complete Replacement Grinder | When a rebuild doesn’t stack up, we quote a like-for-like N.Mac from the model on your nameplate. | |
How we confirm the exact part: N.Mac parts depend on grinder size, inline or channel version, stack height and cutter tooth count. Your nameplate carries the model (e.g. N.Mac 150I or N.Mac 250C) and the serial number NETZSCH uses to trace the original build. Tick the items above and add a nameplate photo, and we’ll confirm the correct parts for your exact grinder.
Models
Spare parts are available for every N.Mac size in the published range; the number is the nominal flow in m³/h, with “I” for inline (pipe-mounted) and “C” for channel versions.
Models & Key Specifications
| Model | Installation | Flow (m³/h) | Pressure drop (bar) | Max. pressure (bar) |
|---|---|---|---|---|
| N.Mac 50I | Inline (flanged) | 50 | 0.05 | 6 |
| N.Mac 150I | Inline (flanged) | 150 | 0.12 | 6 |
| N.Mac 350I | Inline (flanged) | 350 | 0.08 | 6 |
| N.Mac 50C | Channel | 50 | – | – |
| N.Mac 120C | Channel | 120 | – | – |
| N.Mac 250C | Channel | 250 | – | – |
| N.Mac 400C | Channel | 400 | – | – |
All sizes: 2.2–4 kW motors, gear reduction about 1:29, hardened hexagonal shafts, cutter discs with 3, 5, 7 (standard), 9 or 11 teeth, mechanical seals with quench in bearing and seal cartridges; further sizes on request.
Troubleshooting
Solids passing through too coarse
Likely cause: blunt or chipped cutter discs, worn spacers opening the cutting gap, or a tooth count too coarse for the duty. Action: inspect the cutting stack; replace cutters and spacers together, or exchange the complete cutting cartridge; consider a cutter with more teeth for a finer result.
Grinder jams or stalls
Likely cause: rags, wipes or hard objects wedged between the cutters, or a stack too worn to bite cleanly. Action: isolate and clear the stack; fit or check the reversing control so jams clear automatically; fit a cleaning comb on fibrous media; replace worn cutters.
Motor trips repeatedly
Likely cause: repeated jams, overload from heavy solids, a failing gearbox, or a phase fault. Action: check the motor current and supply on all phases; check the reversing control settings; inspect the gearbox and bearings for drag.
Rags wrapping around the shafts
Likely cause: long fibrous material collecting between the cutters with no comb or brush fitted, or a worn comb. Action: fit or replace the cleaning comb / brush; clean the stack and check spacers for wear.
Leaking at the shaft seal or quench
Likely cause: worn mechanical seal faces from grit, or the quench running dry or contaminated. Action: check the quench level and condition; replace the mechanical seal and O-rings, or the bearing and seal cartridge if product has reached the bearings.
Noise or vibration
Likely cause: worn bearings, a hard object in the cutting chamber, a bent shaft, or worn gearbox teeth. Action: isolate and remove any foreign object; check shaft run-out and bearing condition; replace the bearing cartridge or shaft as needed.
High pressure drop across an inline grinder
Likely cause: a part-blocked cutting chamber or rag build-up on the stack. Action: clear the cutting chamber; check reversing and comb operation; review upstream screening if blockages recur.
Request for Quotation
Selected Parts:
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Not sure which parts? Just send a photo of the nameplate or part below.