ForConstructionPros.com

Kim Johnston

If you run a milling machine, then you know that wear is going to occur. But there are some areas of the machine that naturally wear more than others. Below are the major wear parts for half-lane and smaller milling units.

Cutting teeth
The teeth, or tooling, on the drum are probably the biggest wear part of a milling machine because they are in constant contact with the asphalt. These teeth are constantly spinning when grinding the asphalt, but if buildup of material causes a tooth to stop spinning it will cause uneven wear on the tooth, says Tom Chastain, product manager for paving and milling with Dynapac. A worn tooth will affect how well the drum mills. And if the tooth isn't replaced it can wear into the holder and cause more damage to the machine and be costly to repair.

A worn tooth can be visibly seen in two ways. First, a contractor can look at the tooling on the drum and see which teeth are worn or uneven, Chastain says. Round tips indicate even wear, says Jan Schmidt, vice president of product support for Wirtgen America. If a tip is flat on one side it has worn unevenly.

A contractor can also look behind the machine at what he is milling to indicate wear. A worn tooth will produce a solid streak in the milling pattern, according to Chastain.

The lifespan of the teeth varies depending on many different factors. These include the type of material being cut, the depth of the cut, and how fast the milling unit itself is moving, says Schmidt.