Links can be measured with either a depth gauge or an ultrasonic tool. Both methods are shown in the videos below.
- Ultrasonic Tool
- Depth Gauge
Potential Observations
What to look for
Below are some of the issues you should be looking for when inspecting links. This list does not cover all possible issues, but is a starting point that covers most genral issues.
Link Rail Spalling
| Examples | Causes | Effects | Recommendations |
|---|---|---|---|
   |
• Link twisting • High impact loads • Wide shoes • Tight track • Corrosion • Extra machine weight |
• Shortened link structural life • Possible track separation — Severe conditions |
• Check other links & continue to run • Partial Crack — Manage & watch — Weld to finish season for short-term fix • Plan downtime for possible replacement |
Link Scalloping
| Examples | Causes | Effects | Recommendations |
|---|---|---|---|
 |
• Flat surface of link contacting round surface of roller & idler • Primary scallop • Idler contact (1 vs. 2 idlers) • Machine balance • Secondary scallop • Link hinge |
• Poor fine grading • Machine vibration • Reduced idler and link wear life |
• Proper track tension • Proper machine balance • Abrasive material guarding on track frames • Periodic cleaning of track roller frames |
Pin Boss wear - Guiding
| Examples | Causes | Effects | Recommendations |
|---|---|---|---|
 |
• Improper track adjustment • Poor track guiding — Primary • Moving u/c (i.e. Links & rollers) — Secondary • Stationary & moving u/c (i.e. Links & track guides) • Insufficient roller/flange height (Generally new U/C components) • Insufficient pin coverage of stationary track guides• Accelerated guide wear on twister resister - Elevated • Equalizer bar bearing wear |
• Reuse of component • Structural concerns • Loss of pin retention • Generation of end play - dry joints • Cost of turn |
• Proper track tension • Improved track guiding — Primary • Tall double flange rollers • Increase idler flange height — Secondary • End guiding guards • Center guiding guards • Full length guards |
Pin Boss Wear - Roller Contact
| Examples | Causes | Effects | Recommendations |
|---|---|---|---|
 |
• Roller flange contacting link pin boss • Link/Roller system exceeds 200% — For any one roller — Typically an end roller first |
• Inability to reuse or rebuild link — Loss of pin retention and/or oil • Inability to rebuild rollers • Loss of structural integrity • Machine ride |
• Swap rollers • Rebuild/Exchange rollers • Cut roller flanges • Continue running to end of link life or destruction |
Side Rail Wear
| Examples | Causes | Effects | Recommendations |
|---|---|---|---|
 |
• Roller flange in constant contact w/ side of link • Constant turn in same direction • Work in uneven terrain • Sidesloping • New U/C in low abrasion applications — More likely to see this • Frame misalignment |
• Cosmetic only | • Continue running track • Alternate turning • Direction change when sideslope working |
Shoe to link Contact
| Examples | Causes | Effects | Recommendations |
|---|---|---|---|
 |
• Lack of solid abutment • Improper tightening procedures • Inadequate cleaning shoe & link face prior to assembly (Paint, dirt, rust, etc.) |
• Track shoe bolt loosening • Bolt breakage • Link cracking • Shoe cracking |
• Proper bolt tightening procedures • Clean shoe & link faces prior to assembly • Be sure link & shoe contact around link bolt holes • Good shoe to link contact: produces shiny pattern around bolt holes |
Master Link Strap Notch
| Examples | Causes | Effects | Recommendations |
|---|---|---|---|
 |
• Shoe notch hitting bushing strap — Due to handling after shoes assembled to chain • Wide shoes • High impact loading |
• Possible bushing strap cracking | • Possible concern depending on severity — Wide shoes, high impact • May be cosmetic — Narrow shoes, low impact |
Master Link Strap Cracking
| Examples | Causes | Effects | Recommendations |
|---|---|---|---|
 |
• High impact loads • Wide shoes • Improper bolt torquing • Improper assembly |
• Link cracking in bushing strap area • Track separation |
• Monitor • Plan for scheduled downtime to replace |
Link Cracking
| Examples | Causes | Effects | Recommendations |
|---|---|---|---|
 |
• Link twisting • High impact loads • Wide shoes • Tight track • Corrosion • Extra machine weight |
• Shortened link structural life • Possible track separation — Severe conditions |
• Check other links & continue to run • Partial Crack — Manage & watch — Weld to finish season for short-term fix • Plan downtime for possible replacement |
Additional Link Cracking
| Examples | Causes | Effects | Recommendations |
|---|---|---|---|
 |
• Potential Corrosion from: — Phosphate — Coal — Sulfur • High impact loading • Wide shoes |
• Severe cracking: — Possible link breakage, track separation • Minor cracking: — Mostly cosmetic |
• Severe cracking: — Schedule replacement • Minor cracking: — Monitor for propagation; continue to run — Typically cosmetic |
Bushing Strap Inside face Wear
| Examples | Causes | Effects | Recommendations |
|---|---|---|---|
 |
• Sidesloping • Segment contact w/ bushing strap face • Misalignment of carrier roller |
• Reuse of component • Structural concerns • Loss of pin retention • Generation of end play - dry joints • Cost of turn |
• Proper track tension • Improved track guiding — Primary • Tall double flange rollers • Increase idler flange height — Secondary • End guiding guards • Center guiding guards • Full length guards |
Link As. Pin Extension
| Examples | Causes | Effects | Recommendations |
|---|---|---|---|
 |
• Assembly related — 1 side set to specific dimensions; other side floats |
• Visual only | • Track OK |