Introduction to Basic Manufacturing Processes and ... - always yours

390 Introduction to Basic Manufacturing Processes and Workshop Technology
19.2.5.5.1 Types of reamers
The reamers are classified as under.
(i)
(ii)
(iii)
(iv)
(v)
(vi)
(vii)
(viii)
Hand reamer
Machine reamers
Parallel reamer
Taper reamer
Reamers with straight flutes
Reamers with spiral flutes
Adjustable reamer
Expanding reamer
Some common types of reamer generally used in fitting shops are discussed as under.
19.2.5.5.1.1 Hand reamer
Hand reamer is operated or rotated by hand to finish holes and remove its ovality. Its
cutting edges are backed off in the same manner as those of twist drills to give suitable
clearance. It is made up of carbon or high speed steel. It is used for very fine internal turning
in the hole by placing a tap wrench on the squared end of the reamer.
19.2.5.5.1.2 Machine reamer
Machine reamer is designed for slow speeds for use on drill presses, lathes, vertical
milling machines etc. It is chamfered on the front side of cutting edge. It possesses straight
or tapered shanks and comprises of either straight or spiral flutes.
19.2.5.5.1.3 Taper reamer
Taper reamer is widely used for finishing taper holes smoothly and accurately. It is also
used to provide a taper to a drilled hole when a taper pin is to be used. It is generally
performed with either straight or spiral flutes. It has spaces ground into the cutting edges
or teeth to prevent overloading the entire length of each tooth of the reamer. These spaces
are staggered on the various teeth to help in stock removal. The spiral fluted reamer has a
shearing action that eliminates chatter and is generally preferred. Large size taper reamers
are made in both roughing and finishing types. When a large amount of stock is to be
removed, a roughing reamer is generally used. The finishing reamer is commonly employed
to control size and smooth the hole.
19.2.5.5.1.4 Spiral fluted reamer
Spiral fluted reamer performs greater shearing action than one with straight flute.
19.2.5.6 TAPS
Taps are used for cutting or producing internal threads of either left or right hand kind
in nuts or pre-drilled holes. Taps are threaded externally. The threads being cut by grinding
to give a high class finish. Taps are made up of alloy steel or hardened steel. To provide
cutting edges, grooves known as flutes are ground along the threaded portion of the tap so
that the thread is divided into rows of teeth. The number of flutes on tap varies from two
to eight whereas four being the most common. The flutes acts as channels to carry away the
chips formed during tapping or cutting threads. The nomenclature of a typical tap is shown