Longitudinal center line which is concentric with diameter of reamer is known as

Reaming is a cutting process that uses a cutting tool to create a hole of a precise size. Reaming is performed on a hole that has already been drilled to create a circular hole with the correct diameter.  Reaming is a finishing operation that follows drilling or boring. It involves the use of a multi-fluted cutting tool called a reamer that removes a small amount of material from the hole surface to achieve the desired dimension and finish.  Reaming involves widening the opening of a hole. Reaming is done for two purposes: to bring holes to a more exact size and to improve the finish of an... Show more

Reaming is a cutting process that uses a cutting tool to create a hole of a precise size. Reaming is performed on a hole that has already been drilled to create a circular hole with the correct diameter. 
Reaming is a finishing operation that follows drilling or boring. It involves the use of a multi-fluted cutting tool called a reamer that removes a small amount of material from the hole surface to achieve the desired dimension and finish. 
Reaming involves widening the opening of a hole. Reaming is done for two purposes: to bring holes to a more exact size and to improve the finish of an existing hole. 

A reamer is a rotary cutting tool used in metalworking. Precision reamers are designed to enlarge the size of a hole by a small amount, but with a high degree of accuracy to leave smooth sides.

Here are some types of reamers:
Chucking Reamers: The most widely used reamer and commonly used in lathes to enlarge smooth holes.
Morse Taper Reamers: Used to finish morse taper holes or sleeves.
Automotive Reamers: Used to ream steel for car parts such as steering arms, ball joints, and tie rod ends in vehicles. 

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