7-7.5 Adjustable Hand Reamers

An adjustable hand reamer can cover a small range of sizes. They are generally referenced by a letter which equates to a size range. The disposable blades slide along a tapered groove.

The act of tightening and loosening the restraining nuts at each end varies the size that may be cut.

The absence of any spiral in the flutes restricts them to light usage (minimal material removal per setting) as they have a tendency to chatter.

They are also restricted to usage in unbroken holes. If a hole has an axial split along it, such as a split bush or a clamping hole, each straight tooth will in turn drop into the gap causing the other teeth to retract from their cutting position. This also gives rise to chatter marks and defeats the purpose of using the reamer to size a hole.