Turning
Content
Noorazlindawati Mohd Norman
02186141
Section 1
OBJECTIVE:
To know all the turning methods involving the lathe machine and to know
the operation of lathe machine.
APPARATUS:
Universal lathe machine
Large spanner
Small spanner
L-square
Vernier caliper
Center drill
6 mm drill
8.5 mm drill
10 mm drill
Knurling tool holder
Grooving tool holder
Facing tool holder
Chamfering tool holder
Goggles
Tool holder opener/fastener
Chucking tool
Procedure:
Turning part 1
1. A high-speed steel metal measured about 50mm x 8mm x 8mm was given to
be made into a cutting tool.
2. The tool bit was produced as marked by grinding off the unwanted parts by
using the bench metal grinding machine.
3. The nose radius was done by repeatedly sliding the front edge slightly on the
oilstone.
4. The machine was first switched on. The tool bit was attached to the tool
holder, and the tool holder was attached to the machine and tightened using
tool post.
5. The cylindrical workpiece was clamped firmly on the center of the chuck. The
chuck was tightened using chuck wrench.
6. The tool bit was set to be on the center and this was made sure by centering it
with the tail stock center point.
Noorazlindawati Mohd Norman
02186141
Section 1
7. Facing is an operation of decreasing the length of the workpiece to a specified
dimension by cutting the circular area of the workpiece, obtaining a flat and
smooth surface.
8. First, the tool bit was set to be 45° from the edge of the surface of the
workpiece.
9. The switch was turned on and the workpiece will start to rotate with a speed of
860 rpm.
10. The roughing depth of cut for this process is 2mm while the finishing depth of
cut is 0.2 mm.
11. The cross handwheel (x-axis) was used during this facing process.
12. Facing was done on one end of the workpiece and then the other end until the
length of the cylinder reaches 70mm.
13. Turning is done to reduce the diameter of the workpiece by cutting off the
sides of the workpiece in the y direction.
14. The apron handwheel was used during this process.
15. The tool bit was set to be 3° from the surface of the workpiece. The speed is
still 860 rpm and the feed rate is 0.1.
16. Vernier caliper was used to check the diameter of the workpiece until it
reaches the required diameter that is 40mm.
17. The next step is drilling a Ø14mm x 50mm deep hole. To start drilling, the
tailstock was changed to a drill chuck.
18. Center drill was attached to the drill chuck and the workpiece was turned on to
rotate. The center drill was moved into the center of the base using the tail
stock handwheel.
19. 1 rotation of the dialstock is equivalent to 5mm depth of displacement. So a
total of 10 rotations must be made.
20. The drill was then changed to Ø6mm drill. The tail stock handwheel was
rotated clockwise by one rotation deep into the workpiece and then rotated
counter-clockwise to remove the chips inside the hole. The drill was inserted
by 10mm gradually until the depth reaches 50mm.
21. The drill was again changed to Ø8mm, Ø12mm and finally to a Ø14mm drill.
The same process was repeated for all drills.
Noorazlindawati Mohd Norman
02186141
Section 1
22. Grooving is a process to obtain a slit hole using another type of cutting tool.
23. From the same end, the workpiece was measured 10mm and 15mm. A
groove of 5mm will be removed until the groove is 30mm in diameter.
24. The previous tool bit was changed to cut off tool and set to be 90°, parallel to
the surface.
25. The cutting tool was moved 10mm from the edge of the workpiece and started
grooving. As the width of the cutting tool is 2.5 mm, double grade was needed
in order to get a 5mm groove.
26. The process was carried on until the diameter reaches 30mm.
Turning part II
27. The other part of the workpiece was now dealt with. First, using the previous
turning technique, the outermost diameter was reduced to 20mm for 15mm
length.
28. The outermost 10mm length was reduced more to 14mm in diameter.
29. Taper is defined as a uniform increase of diameter in a certain length.
30. To perform tapering, the top slide was set to a certain desired angle, while the
tool post was set to its normal position, which was right angle from the top
slide.
31. The required angle was calculated from the measurements of the workpiece.
For this project, the required angle was: tanֿ¹ (10/35) = 15.9° ≈ 16°. Therefore,
the top slide was set to 16°.
32. During the process, only the cross handwheel and top slide were used. Cross
handwheel controls the feed while the topside handwheel was used to make
the tapering cut by moving the cutting tool in the direction of 16° along the
workpiece.
33. This procedure was repeated until the taper reaches the 20mm diameter x
5mm part.
34. Then, chamfering was made at the edge of the 14mm diameter.
35. Another type of cutting tool was used for this process that is the 45° tool.
36. Firstly, the top slide was set back to its original position, and the tool was set
parallel to the surface of the workpiece.
Noorazlindawati Mohd Norman
02186141
Section 1
37. After that, the tool was set to the edge of the workpiece. The workpiece was
rotated, and the apron handwheel was moved 1.5mm to do the chamfering.
38. The same chamfering procedure was repeated for the other end of the
workpiece. This time the apron handwheel was moved to 2mm.
39. A knurl is a raised impression on the surface of the workpiece produced by
two hardened rolls, usually one of two patterns, diamonds or straight. In this
project, the diamond pattern was used.
40. The speed was changed to 30rpm and the feed rate was 0.476 mm for this
process.
41. The tool bit tool holder was changed to a diamond knurl holder, and it was set
5° to the surface. The knurls were also centered on the workpiece vertically.
The knurling process was repeated a few times until a satisfying knurl was
obtained
Introduction:
Cutting tools
A cutting tool is used to remove metal in the form of small chips. The process
is termed as machining and is perhaps the most versatile manufacturing process.
The machine that provides the necessary relative motions between the work and the
cutting tool is commonly known as the machine tool.
Tool angles
If a cutting tool is to shear or cut the metal efficiently, it is important that angles
have the correct values according to the machining operation and the metal being
machined. The figure above shows the angles of a single point turning tool. The
normal order in which the angles are mentioned according to the American standard
system is also shown in the figure above.
Sliding cut
The primarily purpose of center lathe is the production of cylindrical surfaces.
The cutting tool moves along a path parallel to the center line of the work as shown
in the figure above. A standard straight edges single point tool would be suitable for
these operations. The cuts must always be taken towards the headstalk as greater
rigidly is obtained.
Facing cut
If the tool follows a path at 90 degrees to the lathe center line a plane surface
can be produced at the ends of the cylinder. This is achieved through the movement
Noorazlindawati Mohd Norman
02186141
Section 1
of the cross slide. If the tools move towards the center line the technique is known as
surfacing inwards. If the tool moves away from the center line the technique is known
as surfacing outwards.
Drilling and reaming
Drilling at the center lathe is achieved by using tailstock as tool holding
device. Twist drill is used for drilling and taper shank reamer is used for reaming
operations. Both drilling and reaming technique are shown in the figure in the
previous page. Drilling using the lathe machine can produce accurate centered
holes. Drilling also can produce good surface finish holes, but the depth of the hole is
limited by the length of the drill tool. Reaming can produce good surface finish of the
hole.
Boring
When holes require accurate diameter, the boring technique is often used.
The boring tool is held in the tool post. If a tapered hole is needed, the compound
slide is indexed at one-half the included angle of the taper.
Noorazlindawati Mohd Norman
02186141
Section 1
Taper turning
It can only be achieved only when the tool traverses a path not parallel with the
lathe center. There are two main methods, shown in the above diagrams, for
producing a taper turning.
a) By tilting the compound slide
b) By offsetting the tailstock
The advantage of taper turning is that it has the ability to align and hold machine
parts and can be realigning anytime.
Noorazlindawati Mohd Norman
02186141
Section 1
Knurling
Knurling is required to provide superior gripping effect. The knurling operation
consists of deformation of the workpiece using a hardened knurling roller. However
in the knurling operation, the fit has less contact area than a standard fit.
Noorazlindawati Mohd Norman
02186141
Section 1
DISCUSSION:
The modern center lathe machine is capable of generating a round or flat
surface. The work piece is revolved about its center line, while the tool, held in a
suitable tool post, follows a predetermined path. Therefore, all lathe machine has the
following attributes:
i.
ii.
iii.
iv.
Device for holding the work piece
Device for holding the tool
Rotation of the work or tool
Arrangement for movement of the work or tool
A cutting tool is used to remove metal in the form of small chips. The process is
termed machining and is perhaps the most versatile manufacturing process. The
machine that provides the necessary relative motions between the work and the
cutting tool is commonly known as the machine tool. If a cutting tool is to shear or cut
the metal efficiently, it is important that angles have the correct values according to
the machining operation and the metal being machined.
The primarily purpose of center lathe is the production of cylindrical surfaces. The
cutting tool moves along a path parallel to the center line of the work. Hence, a lathe
machine can do sliding cuts, facing cuts, taper turning, knurling, drilling, reaming and
boring.
The lathe machine has indeed given human an advantage in producing mass
cylindrical components. Cylindrical specimen can be shaped with ease in no time
and with good accuracy and good surface finish. The lathe machine saves us time
and energy.
However, in the workshop, some difficulty in handling the lathe machine has
occurred. First, the carriage hand wheel, cross feed hand wheel and tool post slide
hand wheel are already loose, making it hard to acquire good accuracy. This causes
major problem especially if I wish to return backwards, or in other words, to return
back to my starting point of lathing operation. Second, simultaneously the oil in the
lathe machine ran out and this further hinders progress in lathing. Third, in my
opinion, the broken tool holders should be separated from the working ones in the
tool cabinet. More than once I’ve accidentally picked broken or bad shaped tool
holders that make it irritating and time wasting.
Noorazlindawati Mohd Norman
02186141
Section 1
CONCLUSION:
As a conclusion, in the end of the turning project, I’ve managed to understand
and know how to operate a lathe machine. I’ve also able to identify and differentiate
the various turning methods such as facing, grooving, knurling, drilling, reaming and
boring. But the most important thing is that I know the function of the lathe machine
and operate it by myself. Hence, my knowledge about workshop machineries have
expanded and I’ve gained valuable experience. In the end of the turning project, I’ve
also managed to produce the required turning specimen. The above diagram shows
the tool shape that would enable nearly all turning operations to be carried out
satisfactorily.
Question:
a) Calculate the cutting speeds for the sliding cuts required for rough turning.
Calculate the RPM required to turn a mild steel shaft if the diameter is
a) 150mm
Cutting speed = D N/1000
b) Determine the cutting speed for machining a work piece 120 mm in diameter at
a spindle speed N= 500 rpm.
Cutting speed = D N/1000
= 3.142 x 120 x 500 / 1000
= 188.52 rev/min
c) Determine the rotational speed of the lathe spindle in machining a workpiece 80
mm in diameter at a cutting speed 215m/min.
Spindle speed N = 1000 x cutting speed / 3.142 x D
= 1000 x 215 / 3.142 x 80
= 855.35 rpm
02186141
Section 1
OBJECTIVE:
To know all the turning methods involving the lathe machine and to know
the operation of lathe machine.
APPARATUS:
Universal lathe machine
Large spanner
Small spanner
L-square
Vernier caliper
Center drill
6 mm drill
8.5 mm drill
10 mm drill
Knurling tool holder
Grooving tool holder
Facing tool holder
Chamfering tool holder
Goggles
Tool holder opener/fastener
Chucking tool
Procedure:
Turning part 1
1. A high-speed steel metal measured about 50mm x 8mm x 8mm was given to
be made into a cutting tool.
2. The tool bit was produced as marked by grinding off the unwanted parts by
using the bench metal grinding machine.
3. The nose radius was done by repeatedly sliding the front edge slightly on the
oilstone.
4. The machine was first switched on. The tool bit was attached to the tool
holder, and the tool holder was attached to the machine and tightened using
tool post.
5. The cylindrical workpiece was clamped firmly on the center of the chuck. The
chuck was tightened using chuck wrench.
6. The tool bit was set to be on the center and this was made sure by centering it
with the tail stock center point.
Noorazlindawati Mohd Norman
02186141
Section 1
7. Facing is an operation of decreasing the length of the workpiece to a specified
dimension by cutting the circular area of the workpiece, obtaining a flat and
smooth surface.
8. First, the tool bit was set to be 45° from the edge of the surface of the
workpiece.
9. The switch was turned on and the workpiece will start to rotate with a speed of
860 rpm.
10. The roughing depth of cut for this process is 2mm while the finishing depth of
cut is 0.2 mm.
11. The cross handwheel (x-axis) was used during this facing process.
12. Facing was done on one end of the workpiece and then the other end until the
length of the cylinder reaches 70mm.
13. Turning is done to reduce the diameter of the workpiece by cutting off the
sides of the workpiece in the y direction.
14. The apron handwheel was used during this process.
15. The tool bit was set to be 3° from the surface of the workpiece. The speed is
still 860 rpm and the feed rate is 0.1.
16. Vernier caliper was used to check the diameter of the workpiece until it
reaches the required diameter that is 40mm.
17. The next step is drilling a Ø14mm x 50mm deep hole. To start drilling, the
tailstock was changed to a drill chuck.
18. Center drill was attached to the drill chuck and the workpiece was turned on to
rotate. The center drill was moved into the center of the base using the tail
stock handwheel.
19. 1 rotation of the dialstock is equivalent to 5mm depth of displacement. So a
total of 10 rotations must be made.
20. The drill was then changed to Ø6mm drill. The tail stock handwheel was
rotated clockwise by one rotation deep into the workpiece and then rotated
counter-clockwise to remove the chips inside the hole. The drill was inserted
by 10mm gradually until the depth reaches 50mm.
21. The drill was again changed to Ø8mm, Ø12mm and finally to a Ø14mm drill.
The same process was repeated for all drills.
Noorazlindawati Mohd Norman
02186141
Section 1
22. Grooving is a process to obtain a slit hole using another type of cutting tool.
23. From the same end, the workpiece was measured 10mm and 15mm. A
groove of 5mm will be removed until the groove is 30mm in diameter.
24. The previous tool bit was changed to cut off tool and set to be 90°, parallel to
the surface.
25. The cutting tool was moved 10mm from the edge of the workpiece and started
grooving. As the width of the cutting tool is 2.5 mm, double grade was needed
in order to get a 5mm groove.
26. The process was carried on until the diameter reaches 30mm.
Turning part II
27. The other part of the workpiece was now dealt with. First, using the previous
turning technique, the outermost diameter was reduced to 20mm for 15mm
length.
28. The outermost 10mm length was reduced more to 14mm in diameter.
29. Taper is defined as a uniform increase of diameter in a certain length.
30. To perform tapering, the top slide was set to a certain desired angle, while the
tool post was set to its normal position, which was right angle from the top
slide.
31. The required angle was calculated from the measurements of the workpiece.
For this project, the required angle was: tanֿ¹ (10/35) = 15.9° ≈ 16°. Therefore,
the top slide was set to 16°.
32. During the process, only the cross handwheel and top slide were used. Cross
handwheel controls the feed while the topside handwheel was used to make
the tapering cut by moving the cutting tool in the direction of 16° along the
workpiece.
33. This procedure was repeated until the taper reaches the 20mm diameter x
5mm part.
34. Then, chamfering was made at the edge of the 14mm diameter.
35. Another type of cutting tool was used for this process that is the 45° tool.
36. Firstly, the top slide was set back to its original position, and the tool was set
parallel to the surface of the workpiece.
Noorazlindawati Mohd Norman
02186141
Section 1
37. After that, the tool was set to the edge of the workpiece. The workpiece was
rotated, and the apron handwheel was moved 1.5mm to do the chamfering.
38. The same chamfering procedure was repeated for the other end of the
workpiece. This time the apron handwheel was moved to 2mm.
39. A knurl is a raised impression on the surface of the workpiece produced by
two hardened rolls, usually one of two patterns, diamonds or straight. In this
project, the diamond pattern was used.
40. The speed was changed to 30rpm and the feed rate was 0.476 mm for this
process.
41. The tool bit tool holder was changed to a diamond knurl holder, and it was set
5° to the surface. The knurls were also centered on the workpiece vertically.
The knurling process was repeated a few times until a satisfying knurl was
obtained
Introduction:
Cutting tools
A cutting tool is used to remove metal in the form of small chips. The process
is termed as machining and is perhaps the most versatile manufacturing process.
The machine that provides the necessary relative motions between the work and the
cutting tool is commonly known as the machine tool.
Tool angles
If a cutting tool is to shear or cut the metal efficiently, it is important that angles
have the correct values according to the machining operation and the metal being
machined. The figure above shows the angles of a single point turning tool. The
normal order in which the angles are mentioned according to the American standard
system is also shown in the figure above.
Sliding cut
The primarily purpose of center lathe is the production of cylindrical surfaces.
The cutting tool moves along a path parallel to the center line of the work as shown
in the figure above. A standard straight edges single point tool would be suitable for
these operations. The cuts must always be taken towards the headstalk as greater
rigidly is obtained.
Facing cut
If the tool follows a path at 90 degrees to the lathe center line a plane surface
can be produced at the ends of the cylinder. This is achieved through the movement
Noorazlindawati Mohd Norman
02186141
Section 1
of the cross slide. If the tools move towards the center line the technique is known as
surfacing inwards. If the tool moves away from the center line the technique is known
as surfacing outwards.
Drilling and reaming
Drilling at the center lathe is achieved by using tailstock as tool holding
device. Twist drill is used for drilling and taper shank reamer is used for reaming
operations. Both drilling and reaming technique are shown in the figure in the
previous page. Drilling using the lathe machine can produce accurate centered
holes. Drilling also can produce good surface finish holes, but the depth of the hole is
limited by the length of the drill tool. Reaming can produce good surface finish of the
hole.
Boring
When holes require accurate diameter, the boring technique is often used.
The boring tool is held in the tool post. If a tapered hole is needed, the compound
slide is indexed at one-half the included angle of the taper.
Noorazlindawati Mohd Norman
02186141
Section 1
Taper turning
It can only be achieved only when the tool traverses a path not parallel with the
lathe center. There are two main methods, shown in the above diagrams, for
producing a taper turning.
a) By tilting the compound slide
b) By offsetting the tailstock
The advantage of taper turning is that it has the ability to align and hold machine
parts and can be realigning anytime.
Noorazlindawati Mohd Norman
02186141
Section 1
Knurling
Knurling is required to provide superior gripping effect. The knurling operation
consists of deformation of the workpiece using a hardened knurling roller. However
in the knurling operation, the fit has less contact area than a standard fit.
Noorazlindawati Mohd Norman
02186141
Section 1
DISCUSSION:
The modern center lathe machine is capable of generating a round or flat
surface. The work piece is revolved about its center line, while the tool, held in a
suitable tool post, follows a predetermined path. Therefore, all lathe machine has the
following attributes:
i.
ii.
iii.
iv.
Device for holding the work piece
Device for holding the tool
Rotation of the work or tool
Arrangement for movement of the work or tool
A cutting tool is used to remove metal in the form of small chips. The process is
termed machining and is perhaps the most versatile manufacturing process. The
machine that provides the necessary relative motions between the work and the
cutting tool is commonly known as the machine tool. If a cutting tool is to shear or cut
the metal efficiently, it is important that angles have the correct values according to
the machining operation and the metal being machined.
The primarily purpose of center lathe is the production of cylindrical surfaces. The
cutting tool moves along a path parallel to the center line of the work. Hence, a lathe
machine can do sliding cuts, facing cuts, taper turning, knurling, drilling, reaming and
boring.
The lathe machine has indeed given human an advantage in producing mass
cylindrical components. Cylindrical specimen can be shaped with ease in no time
and with good accuracy and good surface finish. The lathe machine saves us time
and energy.
However, in the workshop, some difficulty in handling the lathe machine has
occurred. First, the carriage hand wheel, cross feed hand wheel and tool post slide
hand wheel are already loose, making it hard to acquire good accuracy. This causes
major problem especially if I wish to return backwards, or in other words, to return
back to my starting point of lathing operation. Second, simultaneously the oil in the
lathe machine ran out and this further hinders progress in lathing. Third, in my
opinion, the broken tool holders should be separated from the working ones in the
tool cabinet. More than once I’ve accidentally picked broken or bad shaped tool
holders that make it irritating and time wasting.
Noorazlindawati Mohd Norman
02186141
Section 1
CONCLUSION:
As a conclusion, in the end of the turning project, I’ve managed to understand
and know how to operate a lathe machine. I’ve also able to identify and differentiate
the various turning methods such as facing, grooving, knurling, drilling, reaming and
boring. But the most important thing is that I know the function of the lathe machine
and operate it by myself. Hence, my knowledge about workshop machineries have
expanded and I’ve gained valuable experience. In the end of the turning project, I’ve
also managed to produce the required turning specimen. The above diagram shows
the tool shape that would enable nearly all turning operations to be carried out
satisfactorily.
Question:
a) Calculate the cutting speeds for the sliding cuts required for rough turning.
Calculate the RPM required to turn a mild steel shaft if the diameter is
a) 150mm
Cutting speed = D N/1000
b) Determine the cutting speed for machining a work piece 120 mm in diameter at
a spindle speed N= 500 rpm.
Cutting speed = D N/1000
= 3.142 x 120 x 500 / 1000
= 188.52 rev/min
c) Determine the rotational speed of the lathe spindle in machining a workpiece 80
mm in diameter at a cutting speed 215m/min.
Spindle speed N = 1000 x cutting speed / 3.142 x D
= 1000 x 215 / 3.142 x 80
= 855.35 rpm
