Which tool is used for finishing a circular hole?

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ALP CBT 2 Electrician Previous Paper: Held on 22 Jan 2019 Shift 2

Answer 1

The half-round file is used for finishing a circular hole.
One typical series for hole making can be - (i) Centering, (ii) Drilling, (iii) Boring, (iv) Reaming and (v) Honing.
Centering is carried out to locate the hole by using chisel for easy and accurate alignment of a drill. Although it is optional, centering can improve precision. Drilling is a process of originating a hole, while boring enlarges the diameter of an existing hole. Reaming and honing are used to improve the surface finish and tolerance of the existing hole.
Drilling: Drilling is a cutting process that uses a drill bit to cut or enlarge a hole of circular cross-section in solid materials. The drill bit is a rotary cutting tool.
Boring: Boring is an operation to enlarging of an existing hole, which may have been made by a drill or maybe the result of a core in a casting.
Reaming: Reaming is a sizing operation that removes a small amount of metal from a hole already drilled. It is done for two purposes: to bring holes to a more exact size and to improve the finish of an existing hole.
Honing is a superfinishing process carried out using abrasive sticks or half-round file for the removal of stock from metallic and non-metallic surfaces. This process produces a high surface finish, corrects the profiles of cylindrical surfaces, removes taper.