A girth gear turning a rotary kiln carries the full torque of tonnes of rotating refractory, feed, and clinker, and it only gets one chance to mesh correctly with the pinion on every rotation. Backlash set too tight overheats the mesh and pits the teeth, backlash set too loose hammers the gear under load reversal, and a dry mesh wears through hardened tooth flanks in a single campaign. This checklist covers what to verify across gear mesh, lubrication, and wear and alignment. Sign up to turn this checklist into a guided digital procedure your kiln crew follows on every inspection round.
3 Zones Checked
Gear mesh, lubrication, and wear and alignment covered in this checklist
Full Rotation Scan
Backlash and tooth wear must be checked around the entire gear, not one spot
Continuous Lube Check
How often spray lubrication coverage on the mesh should be confirmed
Zero Tolerance
Room for skipping a backlash reading or a girth gear bolt torque check
Why Girth Gear Checks Can't Be Rushed
A girth gear is not something you swap out over a weekend. Once tooth flanks start pitting or the mesh runs dry, the damage compounds every rotation, and replacement means weeks of kiln downtime instead of a scheduled fix.
Gear Mesh & Backlash Inspection
Backlash Reading Around The Gear
Measure backlash at multiple points around the full gear circumference, not just one accessible spot
Pinion & Gear Mesh Contact Pattern
Check the contact pattern sits centered on the tooth face, since an edge-loaded mesh signals misalignment
Girth Gear Bolt Torque
Verify mounting bolts holding the gear to the kiln shell flange are torqued to spec and none are missing
Make Girth Gear Checks A Habit, Not A Memory
Oxmaint guides your crew through backlash, lubrication, and wear inspections step by step, with photo proof and sign-off logged against each kiln drive. Sign up for a free trial to build your girth gear routine, or book a demo to see it in action.
Lubrication System Checks
Spray Nozzle Coverage
Confirm spray nozzles coat the full tooth width evenly and none are clogged or misaligned
Lubricant Condition & Consistency
Check the open gear grease hasn't hardened, thinned, or picked up kiln dust that would grind into the mesh
Guard & Scraper Condition
Inspect gear guards and grease scrapers so old lubricant is cleared rather than building up on the teeth
Wear & Alignment Checks
Tooth Flank Pitting & Cracking
Look for pitting, spalling, or hairline cracks along tooth flanks, especially near the root of the tooth
Radial & Axial Runout
Measure runout as the kiln rotates to catch a gear that's shifted or a shell that's gone oval
Vibration & Noise Pattern
Note any new whine, knock, or vibration during rotation, since sound often signals wear before it's visible
What A Skipped Check Can Cost You
| Check Skipped |
Likely Consequence |
| Backlash reading |
Mesh runs too tight or loose, accelerating tooth pitting under load |
| Spray nozzle coverage check |
A dry patch on the tooth face wears through the hardened flank |
| Runout measurement |
A shifted gear or oval shell goes unnoticed until the mesh starts hammering |
| Bolt torque check |
A loosened mounting bolt lets the gear shift, throwing off the entire mesh |
Where A CMMS Fits Into Girth Gear Checks
Oxmaint ties this checklist to the girth gear, pinion, and lubrication system as tracked assets, logging backlash readings and lube condition over time so a slow drift toward wear gets flagged early.
Frequently Asked Questions
Q
Why does girth gear backlash need to be checked around the full circumference?
A rotary kiln shell rarely stays perfectly round, so backlash can vary as the gear turns, and checking only one accessible point can miss a tight or loose spot elsewhere on the gear.
Q
What does uneven tooth wear usually indicate?
Wear concentrated on one edge of the tooth face usually points to a misaligned pinion or a gear that has shifted slightly on the kiln shell, rather than normal gradual wear across the whole face.
Q
Can a CMMS track girth gear backlash trends over time?
Yes, a CMMS can log backlash readings against the girth gear asset at each inspection round and flag a gradual drift outside the normal range before it turns into a mesh failure.
Protect Your Kiln Drive From An Avoidable Failure
Oxmaint guides your crew through backlash, lubrication, and wear inspections and logs every reading against the girth gear asset automatically. Sign up for a free trial to build your kiln drive checklist, or book a demo to see it in action.
