FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
The Patent Rules, 2003
Complete Specification
(See section 10 and rule 13)
A Reaming Tool And A Method Of Reaming
Mahindra and Mahindra Ltd.
An Indian company registered under the Indian Companies Act, 1956.
Gateway Building, Apollo Bunder, Mumbai - 400001, Maharashtra, India.
The following specification particularly describes the invention and the manner in which it is to be performed:

A Reaming Tool And A Method Of Reaming
Background to the invention:
In manufacturing operations where a large number of holes or bores are required, a number of tools such as cutting tools, drill bits, or reamers are deployed. A reamer is a type of a cutting tool designed for enlarging and finishing an existing hole. It works by rotational and longitudinal cutting. One key aspect of a reaming operation is that the amount of cuttings should be minimized, especially as compared with the operation involving a drill bit. The primary purpose of a drill bit is to drill a fresh hole whereas that of a reamer is to finish a pre-existing hole to a a greater accuracy or a tighter tolerance with regards the hole geometry and the surface finish.
Reamers usually find their use in high precision machining operations in automobile and aerospace industry or any other industry/ applications where holes need to be made to a tight tolerance.
A typical reamer has a number of flutes which provide cutting edges of a reamer. Based on their configuration, reamers are generally categorized into straight flute reamers and helical flute reamers. As their names suggest, the straight flute reamers include a set of straight flutes situated longitudinally along the reamer body and the helical ones include an array of helical flutes.

As mentioned in the US Patent no. 7207752, some machining applications require that a particular hole being machined by both a straight flute reamer and a helical flute reamer to provide a hole within a desired tolerance. Accordingly, the prior art has also provided reamers having arrays of both straight flutes and helical flutes with cutting edges stepped axially relative to one another, such that a workpiece may experience a first cutting operation and subsequently a second cutting operation provided by a common reamer.
Modern manufacturing processes increasingly require cost effective methods and high quality performance. Hole-making operations typically result in high speeds, pressure and temperatures, thereby adversely impacting life of tools. Due to their high precision nature, typical reamers are expensive and their re-machining (for reusing them) is not uncommon.
There are a number of problems arising out of the physically demanding environment in which the reamers operate.
The problem (and need) of controlling temperatures at the sites of drilling or reaming has been well documented. For example, US patent 6116825 (refer to Figures 1 and 2) suggests that the boring tool, such as a drill, reamer or a rotating tool in general heats up during the cutting process along with the material of which the work piece is made. In automatic mass production operations in particular, cooling and lubrication using a lubricating coolant (designated a

"lubricant" below) is therefore necessary. The application also suggests that in wet machining processes, a large excess of liquid lubricant is introduced into the hole as it is being drilled. This type of lubricating and cooling action entails relatively high costs for equipment, not to mention the costs of the lubricant supply, the necessary cleaning, etc. In drilling operations, moreover, it is not always possible to deliver the lubricant directly into the hole being drilled. Therefore, lubricating systems are used in which the lubricant is transported by means of transport devices via the spindle of a drilling machine and at least one lubricant channel in the drill to the site of the drilling. The site of the drilling is approximately in the vicinity of the major cutting edges or the chip faces of the drill. In these known lubrication systems, a relatively large quantity of lubricant is required to fill the long supply lines which lead from the supply device to the drill or to the spindle of the drill. In addition, a precise and controlled dispensing of small quantities of lubricant is very difficult to achieve using the conventional delivery devices.
The object of the invention disclosed in '825 was therefore to provide a method, as well as a boring tool and tool holder to carry out the method, to accurately dispense a controlled and extremely small quantity of lubricant using technically simple means. They proposed to do so by providing a method for supplying the working parts of a boring tool, in particular a drill, with a lubricant which both cools and lubricates the drill. A dispenser is connected directly or indirectly to the drill to enable lubricant to be fed to the working parts of the drill through at least one channel in the drill. A boring tool, in particular a drill, is also disclosed with a

shaft, a cutter, at least one internal lubricant channel and at least one reservoir being fitted as a dispenser for the lubricant. The reservoir is directly or indirectly connected to the drill by mechanical connections and to the at least one lubricant channel to permit the passage of lubricant. In addition, a tool holder designed to hold the drill is disclosed. The tool holder has an internal dispenser for the lubricant. The dispenser is connected, when the drill is fixed in place, to the at least one lubricant channel in the drill to permit the passage of lubricant. However, taking a look at the invention itself, it is clear that the making of spiral lubricant channels 10 and the radial branch channels 14, or indeed a central hole (10b) as shown in Fig 9, are all complicated operation. Moreover, these arrangements render the tool itself weaker than the ones that have a solid core.
In general, small diameter hole reamers, say below 10mm diameter, require coolant holes for chip removal and lubricating the cutting edge. However these coolant holes, similar to the ones shown in '825 weaken the core of reamer as far as the environment in which they are employed is concerned - that high speed vibratory motion at high temperatures. These typically lead to premature breakages and reduction in working life.
US Patent 7207752 proposes a solution wherein the reaming tool has both straight flutes and helical flutes (Refer to Figures 3 and 4). In this invention, at least a leading portion of the straight flute and the helical flute cutting edges generally lie in a common radial plane for concurrently and collectively performing the

primary and helical cutting operations to a sculpture surface of the workpiece, thereby improving tolerances of the cutting operations, varying the loads imparted the workpiece and the reamer, and reducing heat generated between the workpiece and the reamer. Both of the straight flute and helical flute cutting edges concurrently provide cutting operations to a sculpture surface formed within the pre-existing hole. However, it is seen that the transport of the coolant fluid to the site of cutting and reaming operations is through a core hole (74) assisted by a set of lateral holes (78). The reamer of this invention thus suffers from the drawback that it has become inherently weak.
Another undesirable aspect of the conventional reaming tools is that the coolant used during their operation needs to be clean of any debris or large size impurities lest there would be blockages of the holes and channels through which it is circulated. This problem remains despite the high pressures under which coolants are circulated and filtration systems employed to filter out the debris. It is therefore necessary to eliminate the root cause of this problem.
It is therefore necessary to provide a reamer that would perform to the required level of precision while providing increased tool life.
Object of invention:
An object of the present invention is to provide a reamer that machines within tolerances demanded in manufacturing environments and maximizes the life of

the reamer by minimizing machining loads and heat experienced by the reamer and the associated work piece.
Another object of the present invention is to increase the efficiency of the cutting operations by maintaining the cutting tip sharpened and free of debris (as there is no material build-up at cutting tip).
A further object of the present invention is to take the heat generated during the reaming operation away from the cutting area in real time.
Summary of invention:
The invention provides a reaming tool which has a cutting edge at the tip as well as a longitudinal cutting edge. A flow path for coolant is provided along the external surface of the tool; the flow path being in the form of grooves and flutes. There are no 'internal' holes for the coolant transport. The entire flow of the coolant is on the surface of the reamer and through the longitudinal flutes, thereby ensuring the coolant is directed towards the cutting tip. This arrangement also eliminates the problem faced by conventional reamers where the coolant flow is not adequate where most required and that the tool itself is structurally weakened. In the case of the present invention, the heat generated during cutting is immediately dissipated by the coolant and cuttings/trimmings are carried away by the coolant flow, leaving behind a fresh and clean cutting edge at all times. The

reaming tool of the invention operates at a greater efficiency than conventional reamers; the values of cutting parameters (feed and speed) are higher by 20-30%.
List of Figures:
Figure 1 is a side view of a rotating cutting tool of a prior art in longitudinal section
Figure 2 shows the tool of figure 1, in which the end surface of the drill is connected to a separate detachable container in the form of a dispenser.
Figure 3 is the side elevation of a prior art reamer
Figure 4 is an enlarged partial side view of the reamer of figure 1
Figure 5 shows a longitudinal view of the reaming tool
Figure 6 shows the plan view of the tool taken from the input end.
Figures 7 and 7 A show a perspective view of the front end of the reaming tool
Figures 8 and 8 A show a close up side view of the front end
Figures 9 and 9A show the conventional helical reamer with coolant holes
Figure 10 shows the coolant flow view through conventional helical reamers
Figure 11 shows coolant flow through external grooves provided over straight flute reamer

List of parts:
1. Reamer or reaming too] 9. First groove
2. First Shank 10. First cutting edge
3. Second shank 11. Second cutting edge
4. Longitudinal body or body 12. Longitudinal groove for
5. Input end coolant path
6. Straight flute 13. Cutting fluid or coolant
7. Front end 14. Spindle of reaming machine
8. Transverse face
Detailed description of invention:
The invention discloses a reaming tool that comprises a shank on which a cutting and reaming arrangement and a coolant (13) flow arrangement are provided. It is an extremely simple tool for precision hole-making.
As shown in Figure 5 the reaming tool (or simply reamer) (1) of the present invention comprises a first shank (2), a second shank (3) and a longitudinal body (4) or (simply a body). The first shank (2) has an input end (5) that is adapted to be secured for supporting the reaming tool for rotation and for axial movement relative to an associated workpiece (not shown).
The input end (5) of the reamer (1) is configured for use in a reaming machine for rotary and axial motion. The invention is also used in situations where the

workpiece may be rotated and the reamer (1) remains fixed. This particularly applies in situations where the workpiece is axially translated to feed and the reamer (1) is rotated with the power provided by a spindle (14) and gets guided within a pre-existing hole in a workpiece.
The reamer (1) is preferably made using high strength carbide or steel that is machined from a solid piece of stock material, however, any other suitable material may be used to make the reamer (1) of the invention. The reamer (1) is generally cylindrical; however, it may be of any other suitable cross section.
The body (4) provided near the front end (7) of the reamer includes at least one straight flute (6). As shown in Figure 5, there is provided at the front end (7) of the reamer (1) at least one first cutting edge (10). The number of flutes is preferably two or four but there may be more flutes provided. Each straight flute (6) is also provided with a cutting edge termed as a second cutting edge (11), also straight in configuration. The diameter of the reamer (1) at the front end is slightly smaller than the diameter of the rest of the reaming tool; this helps in guiding the reamer (1) into a pre-existing hole that requires the reaming treatment.
A coolant, which can also double up as a cutting fluid, is typically required at the front cutting tip of the reaming tool during the reaming operation. The coolant (13) is supplied from the input end (5) which fits into the spindle (14) of the tool holder of the reaming machine (see figure 11). On the transverse face (8) of the

reamer (1) (at the input end) there is provided an arrangement of at least one first groove (9) which receives coolant (13) from the spindle (14). Preferably the first grooves (9) are laid in a Y-shape arrangement, emerging from a point as shown in Figure 6. The first grooves (9) are preferably straight but may be of a non-linear configuration. The first grooves (9) facilitate the flow of the coolant (13) released from the spindle (14) into the at least one longitudinal groove (12) that is provided on the longitudinal surface of said first shank (2). The number of first grooves (9) preferably corresponds to the number of longitudinal grooves (12). The 'Y' shaped arrangement, which corresponds to a three-longitudinal-grooves configuration, is a preferred arrangement as it helps distributes the coolant (13) around the reamer (1) evenly.
The longitudinal grooves (12) next make the coolant (13) flow over the surface of the second shank (3) and subsequently into the longitudinally oriented straight flutes and ultimately leading to the set of first cutting edges (10) at a great velocity. This is evident from Figure 11, which visibly shows a greater amount of coolant (13) compared to the coolant (13) seen at the tip for a conventional reamer (Figure 10). It is also evident from Figure 11 that the force of the.coolant (13) at the cutting edge is far greater than that for the conventional reamer. Moreover, the direction of the coolant (13) flow in the reamer (1) of the invention is such (i.e. nearly parallel to the axis of reaming tool) that the removal of the debris is far more effective with the reamer (1) of the invention than in the case of the

conventional reamer. This coolant (13) flow carries away continuously the heat generated during cutting and thus increases the tool life.
The diameters of the first shank (2), second shank (3) and the body (4) may be same. In the preferred embodiment, the diameter of the second shank (3) is less than that of the first shank (2). In another preferred embodiment, the diameter of the second shank (3) is less than those of both the first shank (2) and the body (4). The changes in diameter are preferably accompanied with suitable chamfers.
The longitudinal surface of the second shank (3) is preferably plain.
The relatively sudden change of the diameter at the interface of the two shanks causes turbulence in the coolant (13) flow coming from the first shank (2). The turbulence causes the area over which the coolant (13) flows to widen and facilitates the distribution of the coolant (13) all round the surface of the second shank (3). This advantageously ensures that all straight flutes receive coolant (13) reasonably evenly (which is once again evident from Figure 11).
Any number of the straight flutes with cutting edges may optionally extend at least partially over the surface of the second shank (3). Any number of the longitudinal grooves (12) may optionally extend over the surface of the second shank (3).

It is thus evident that, as an advantage of the present invention, the longitudinal grooves (12) provided in the first shank (2) ensure that the cutting fluid or the coolant (13) which is sent from spindle (14) enters directly in all the longitudinal grooves (12) and passes over the second shank (3) and finally into the straight flutes of the reamer (1) which lubricates each of the first and second cutting edges (10 and 11) of the reaming tool (1). The results of the experiments done using the conventional coolant flow systems (central core and lateral branches) and the reamer (1) of the invention are shown in Figures 10 and 11. It is evident that the distribution of the coolant (13) is more uniform in the reamer (1) of the present invention. It is also apparent that the pressure of the coolant (13) is also adequate for the purpose of carrying the debris being reamed.
It has also been observed that for providing better coolant flow, high pressure and large capacity pumps are used. This leads to high costs of operation.
Example:
A reamer according to the present invention was used to treat pre-existing holes in grey cast iron. The diameter of the pre-existing holes was 8.2mm. The diameters of the first shank, second shank, the body, and the front end were respectively 10mm, 6mm, 8.74mm, and 6.8mm. The number of first grooves was three and there were six straight flutes and six first cutting edges. The rotational speed of the reamer was maintained at 1900 RPM- The coolant used was Blaser 4000 and

supplied at 8-10 bar pressure. The observed feed rate was 412 mm/revolution. The Ra value achieved was between 0.8 to 1.2.
The following advantages are apparent from the consideration of the invention. The reaming tool of the invention has a robust geometric construction which increases its cutting efficiency while offering excellent finish to the workpiece. The grooves provide lubrication to the cutting edge of the tool throughout the cutting operation and at the right location. The following quantifiable advantages have been observed:
- The tool life with existing helical reamer with central core & lateral branches for coolant (13) flow (as measured in linear meters over which the tool is effective) is approximately 37.5 meters whereas with the reamer of the invention provides a tool life effective over approximately 120 meters over the range of 0.020 mm tolerance of part dimensions. Thus the invented reamer provides around 3 times as much the tool life as with a conventional reamer.
- The cost of reamer (1) of the invention (which is solid in construction) is typically less than the existing conventional reamer (which has internal system of holes which is expensive to manufacture)
The range of rotational speed for the reamer (1) of the invention is between 1800-2400RPM though it may be higher or lower. The cutting velocity or the rate at which the reamer (1) progresses down a hole is

found to be between 55-60 m/min as compared with the typical rates of 40-45 m/min for the conventional reamers. This helps to increase the feed during cutting up to 450 mm/rev as compared to conventional feeds of 140 mm/rev. This further helps in increasing the cutting speeds thereby reducing the cutting cycle time, thereby increasing the productivity by 20-30% without any cost addition (Rather deceasing the existing tool cost & increase in tool life).
Since the tool's cutting edges are never allowed to reach undesirably high temperature, the possibility of damage to tool is reduced and tool life is increased. This consequently results in reduction in number of tools required over a period and cost saving to the business. Furthermore the rate of production also increases as frequent tool change is not required. Moreover, due to the simpler construction of the tool of the invention, as compared with the reamers with internal holes and channels, the cost of construction of the tool is also reduced as compared to that of conventional reamers. In addition to this we can desirably increase the cutting parameters, i.e. speed and feed, as the cutting tip is always getting cleaned and not raised to elevated temperature. This helps in increasing directly the productivity without any additional cost. - A further advantage of the reamer (1) of the present invention is that there are no blockages from debris and consequent pressure build-up and tool breakages resulting from them.

Thus the benefits to the manufacturing industry where the tool of the invention is employed as well as to the industry that manufactures the tool itself are evident.
It is evident from the foregoing description that the invention has the following embodiments:
1. A reaming tool comprising a first shank, a second shank and a body wherein
- said first shank has at its input end at least one first groove provided on its transverse surface, and at least one longitudinal groove provided on its longitudinal surface, and a flat to permit engagement with the spindle of a tool holder;
- said second shank has a plain longitudinal surface and has a smaller diameter than first shank;
- a longitudinal body extending axially from said second shank, the body having at least one first cutting edge at its front end and at least one straight flute on its longitudinal surface, wherein said flute is provided with a second cutting edge;
wherein a coolant is released into said first groove at the time of operation of said reaming tool, whereafter said coolant flows into said longitudinal grooves and subsequently onto the longitudinal surface of said second shank and into said at least one longitudinal straight flute, leading

ultimately to said at least one first cutting edge during the operation of said reaming tool.
2. A reaming tool as described in embodiment 1 wherein diameter of said second shank is smaller than the diameter of said first shank.
3. A reaming tool as described in embodiment 1 or 2, wherein diameter of said body is same as or greater than the diameter of said second shank.
4. A reaming tool as described in embodiments no. 1 to 3 wherein the number of said first grooves is preferably three and said first grooves are arranged, in a Y-shape.
5. A reaming tool as described in embodiments no. 1 to 4, wherein the number of said longitudinal grooves is same as the number of said first grooves.
6. A reaming tool as described in embodiment nos. 1 to 5, wherein said first grooves are arranged in a symmetrical arrangement.
7. A reaming tool as described in embodiment nos. 1 to 6, wherein said at least one longitudinal groove at least partially extends over the surface of said second shank.
8. A reaming tool as described in embodiment nos. 1 to 7, wherein said at least one straight flute at least partially extends over the surface of said second shank.
9. A reaming tool as described in embodiment nos. 1 to 8, wherein said reamer has an effective continuous flow path for said coolant from the input end to said at least one first cutting edge.

10. A reaming tool as described in embodiment nos. 1 to 9 wherein said body is generally cylindrical.
11. A reaming tool as described in embodiment nos. 1 to 10, wherein said tool is capable of withstanding a rotational speed in the range between 1800 -2400 RPM.
12. A reaming tool as described in embodiment nos. 1 to 11 wherein said reamer is made from high strength carbide or steel.
13. A method of reaming a preexisting hole in a workpiece, said method comprising the steps of:
a. providing a reaming tool comprising a first shank, a second shank and a
body wherein
said first shank has at its input end at least one first groove provided on its transverse surface, and at least one longitudinal groove provided on its longitudinal surface, and a flat to permit engagement with the spindle of a tool holder;
- said second shank has a plain longitudinal surface and has a smaller diameter than first shank;
- a longitudinal body extending axially from said second shank, the body having at least one first cutting edge at its front end and at least one straight flute on its longitudinal surface, wherein said flute is provided with a second cutting edge;
b. rotating one of said reaming tool or said workpiece, by simultaneously
releasing into said at least one first groove a coolant fluid,

c. translating one of said reaming tool or said workpiece towards each
other so that said reaming tool is fed into said preexisting hole in said
workpiece, and the at least one straight flute carries out a cutting
operation to provide a finish to the internal surface of the preexisting
hole.
d. A method of reaming a preexisting hole in a workpiece as described in
embodiment 13 wherein diameter of said second shank is smaller than
the diameter of said first shank.
e. A method of reaming a preexisting hole in a workpiece as described in
embodiment 13 and 14, wherein diameter of said body is same as or
greater than the diameter of said second shank.
14. A method of reaming a preexisting hole in a workpiece as described in embodiment no. 11 wherein the number of said first grooves is preferably three and said first grooves are arranged, in a Y-shape.
15. A method of reaming a preexisting hole in a workpiece as described in embodiments no. 13 and 14, wherein the number of said longitudinal grooves is same as the number of said first grooves.
16. A method of reaming a preexisting hole in a workpiece as described in embodiment nos. 13 to 15, wherein said first grooves are arranged in a symmetrical arrangement.
17. A method of reaming a preexisting hole in a workpiece as described in embodiment nos. 13 to 16, wherein said at least one longitudinal groove at least partially extends over the surface of said second shank .

18. A method of reaming a preexisting hole in a workpiece as described in embodiment nos. 13 to 17, wherein said at least one straight flute at least partially extends over the surface of said second shank.
19. A method of reaming a preexisting hole in a workpiece as described in embodiment nos. 13 to 18, wherein said reamer has an effective continuous flow path for said coolant from the input end to said at least one first cutting edge
20. A method of reaming a preexisting hole in a workpiece as described in embodiment nos. 13 to 19 wherein said body is generally cylindrical.
21. A method of reaming a preexisting hole in a workpiece as described in
embodiment nos. 13 to 20, wherein said tool rotates at a rotational speed in
the range between 1800 -2400 RPM .
22. A method of reaming a preexisting hole in a workpiece as described in embodiments 13 to 21, wherein the reaming tool advances longitudinally at a rate between 50-60 m/min and 400-450 mm/revolution.
23. A method of reaming a preexisting hole in a workpiece as described in embodiments nos. 13 to 22 wherein said reamer is made from high strength solid carbide or steel.
24. A method of reaming a preexisting hole in a workpiece as described in embodiments nos 13 to 23, wherein the reaming tool advances longitudinally at a rate between 50-60 m/min or 400-450 mm/revolution.

25. A method of reaming a preexisting hole in a workpiece as described in embodiments nos 13 to 24 wherein said reamer is made from high strength solid carbide or steel.
While the above description contains much specificity, these should not be construed as limitation in the scope of the invention, but rather as an exemplification of the preferred embodiments thereof. It must be realized that modifications and variations are possible based on the disclosure given above without departing from the spirit and scope of the invention. Accordingly, the scope of the invention should be determined not by the embodiments illustrated, but by the appended claims and their legal equivalents.

We claim:
1. A reaming tool comprising a first shank, a second shank and a body wherein
said first shank has at its input end at least one first groove provided on its transverse surface, and at least one longitudinal groove provided on its longitudinal surface, and a flat to permit engagement with the spindle of a tool holder; - said second shank has a plain longitudinal surface;
a longitudinal body extending axially from said second shank, the
body having at least one first cutting edge at its front end and at least
one straight flute on its longitudinal surface, wherein said flute is
provided with a second cutting edge;
wherein a coolant is released into said first groove at the time of operation
of said reaming tool, whereafter said coolant flows into said longitudinal
grooves and subsequently onto the longitudinal surface of said second
shank and into said at least one longitudinal straight flute, leading
ultimately to said at least one first cutting edge during the operation of said
reaming tool.
2. A reaming tool as claimed in claim 1 wherein diameter of said second shank is smaller than the diameter of said first shank.
3. A reaming tool as claimed in claims 1 or 2, wherein diameter of said body is same as or greater than the diameter of said second shank.
4. A reaming tool as claimed in claims 1 to 3 wherein the number of said first grooves is preferably three and said first grooves are arranged, in a Y-shape.

5. A reaming tool as claimed in claims 1 to 4, wherein the number of said longitudinal grooves is same as the number of said first grooves.
6. A reaming tool as claimed in claims 1 to 5, wherein said first grooves are arranged in a symmetrical arrangement.
7. A reaming tool as claimed in claims 1 to 6, wherein said at least one longitudinal groove at least partially extends over the surface of said second shank.
8. A reaming tool as claimed in claims 1 to 7, wherein said at least one straight flute at least partially extends over the surface of said second shank.
9. A reaming tool as claimed in claims 1 to 8, wherein said reamer has an effective continuous flow path for said coolant from the input end to said at least one first cutting edge.

10. A reaming tool as claimed in claims 1 to 9 wherein said body is generally cylindrical.
11. A reaming tool as claimed in claims 1 to 10, wherein said tool is capable of withstanding a rotational speed in the range between 1800 -2400 RPM.
12. A reaming tool as claimed in claim nos. 1 to 11 wherein said reamer is made from high strength carbide or steel.
13. A method of reaming a preexisting hole in a workpiece, said method comprising the steps of:
a. providing a reaming tool comprising a first shank, a second shank and a body wherein

said first shank has at its input end at least one first groove provided on its transverse surface, and at least one longitudinal groove provided on its longitudinal surface, and a flat to permit engagement with the spindle of a tool holder; - said second shank has a plain longitudinal surface;
a longitudinal body extending axially from said second shank, the body having at least one first cutting edge at its front end and at least one straight flute on its longitudinal surface, wherein said flute is provided with a second cutting edge;
b. rotating one of said reaming tool or said workpiece, by simultaneously
releasing into said at least one first groove a coolant fluid,
c. translating one of said reaming tool or said workpiece towards each other
so that said reaming tool is fed into said preexisting hole in said
workpiece, and the at least one straight flute carries out a cutting
operation to provide a finish to the internal surface of the preexisting
hole.
14. A method of reaming a preexisting hole in a workpiece as claimed in
claim 13 wherein diameter of said second shank is smaller than the
diameter of said first shank.
15. A method of reaming a preexisting hole in a workpiece as claimed in claims
13 and 14, wherein diameter of said body is same as or greater than the
diameter of said second shank.

16. A method of reaming a preexisting hole in a workpiece as claimed in claims 13 to 15 wherein the number of said first grooves is preferably three and said first grooves are arranged, in a Y-shape.
17. A method of reaming a preexisting hole in a workpiece as claimed in claims 13 to 16, wherein the number of said longitudinal grooves is same as the number of said first grooves.
18. A method of reaming a preexisting hole in a workpiece as claimed in claims 13 to 17, wherein said first grooves are arranged in a symmetrical arrangement.
19. A method of reaming a preexisting hole in a workpiece as claimed in claims 13 to 18, wherein said at least one longitudinal groove at least partially extends over the surface of said second shank .
20. A method of reaming a preexisting hole in a workpiece as claimed in claim 13 to 19, wherein said at least one straight flute at least partially extends over the surface of said second shank.
21. A method of reaming a preexisting hole in a workpiece as claimed in claim 13 to 20, wherein said reamer has an effective continuous flow path for said coolant from the input end to said at least one first cutting edge
22. A method of reaming a preexisting hole in a workpiece as claimed in claims 13 to 21 wherein said body is generally cylindrical.
23. A method of reaming a preexisting hole in a workpiece as claimed in claims 13 to 22, wherein said tool rotates at a rotational speed in the range between 1800-2400 RPM.

24. A method of reaming a preexisting hole in a workpiece as claimed in claims 13 to 23, wherein, the reaming tool advances longitudinally at a rate between 50-60 m/min or 400-450 mm/revolution.
25. A method of reaming a preexisting hole in a workpiece as claimed in claims 13 to 24 wherein said reamer is made from high strength solid carbide or steel.