Reaming is a process which slightly enlarges a pre-existing hole to a tightly toleranced diameter. A reamer is similar to a mill bit in that it has several cutting edges arranged around a central shaft, as shown below. Because of the delicate nature of the operation and since little material is removed, reaming can be done by hand. Reaming is most accurate for axially symmetric parts produced and reamed on a lathe.
Detailed Nomenclature for a Reamer
A more complete listing of reamer nomenclature is provided below.
Reamed Part Design
Reamed holes should not intersect with drilled holes, so the configuration below should NOT be implemented:
As with a drilled hole, clearance for chips is needed at the bottom of a reamed hole. This is illustrated below:
Reaming should not be relied upon to correct the location or alignment of a hole. Its primary purpose is to fine-tune the diameter of the hole.