Reaming Tool

REAMING TOOL

Reamer is a multi-tooth cutter which rotates and moves linearly into an already existing hole. It is used to give a smooth surface as well as close tolerance on the already drilled or bored hole.

Reamer is more like a form tool since the cylindrical shape and size of the reamer is reproduced in the hole. At the bottom of the reamer, the flutes are slightly made tapered to facilitate its entry into the existing hole. Generally, the reamer is expected to cut from the sides, not from the end. The reamer is usually manufactured with two or more peripheral grooves of flutes either parallel to the axis or as a right-angled helix as shown in Figure 3.68 and Figure 3.69.

The reamer with helical flutes provides the smooth shear cutting action and it provides a better surface finish. The pitch of the flutes is made uneven to reduce vibrations. Small size reamers are made with straight shank whereas the large size reamers are made with taper shank. There are different types of reamers for different applications. Shell reamers are used for reaming larger holes. For better dimensional control, adjustable reamers are used. Taper reamers are used for reaming holes to receive taper pins. Since, the reamer follows the already existing hole, any misalignment present in the hole is likely to break the reamer if it is mounted in the conventional spindle. Hence, a floating reamer is used between machine spindle and reamer to adjust for any small misalignment between spindle axis and hole axis.

Reamers are operated at lower speeds and higher feeds than drills of the corresponding diameter. Generally, speeds of reaming will approximately be 60 to 70% of drilling the same material. Feeds may be 2 to 3 times of drilling. Reamers are made of HSS or with carbide tips. Solid carbide reamers are widely used nowadays.