Spring, Detent 

Spring, Detent
Part Number: 2168
Weight: 0.02 lb

Price: $0.67

In stock
Spring, Detent on X1 micro mill.

In your instruction manual, this part appears on the parts list as:

Item No Models
18  Harbor Freight 47158 Central Machinery Micro Mill
Clarke CMD10 Metalworker Micro Mill
Various X1-US SIEG Micro Mill
Click your model to see the complete parts list.