DrillingMachining operation used to create a round hole in a workpart Cutting tool used: Usually performed on a rotating cylindrical tool that has two cutting edges on its working end Tool is referred to as a drill bit Hole diameter is equal to the drill diameter Machine tool used: Drill Press

Components of the Sensitive Drill Press Base: provides stability for the machine and rigid mounting for the column. Usually provided with holes so that it may be bolted to a table or bench. Column: cylindrical post fitted into the base and which provides a solid support for the drill head and worktable. The table may be adjusted to any point between the base and the head. Worktable: either round or rectangular in shape, the worktable provides a flat surface in correct alignment with the drill spindle upon which the workpiece can be positioned.Slots are provided in most tables to allow jigs, fixtures, or large workpieces to be clamped directly to the table. The worktable can be raised, lowered, and swiveled around the column. On some models, the table can even be tilted in either direction for drilling holes on an angle.

DRILLING HEAD Drilling Head: mounted close to the top of the column. It contains the mechanism which is used to revolve the cutting tool and advance it into the workpiece. Made up of the following elements: Motor: provides drive to the spindle. Spindle: a round shaft which is used to hold and drive the cutting tools. Quill: the housing inside which the spindle rotates. Also referred to as the spindle sleeve. It does not revolve but slides up and down inside the head to provide a downfeed for the cutting tool. Handwheel (or hand feed level): used to control the vertical movement of the spindle sleeve and the cutting tool Depth stop: provides a means to control the depth to which a cutting tool enters a workpiece.

Workpiece to be manufactured

Tools and Apparatus used Workpiece provided Drill Press Drill Bits (3mm, 8.5mm and 15mm diameter) Files Try Square Center Punch Vernier height gauge with scriber Tap tools for M10 (tap and tap wrench) Hacksaw Hammer ChiselThe Work piece received was a square shaped andof approximate size of 50 x 50 mm with 6 mm thickness.Procedure The corners are flattened to make a 90o corner out of these surfaces. The workpiece is clamped on the bench vice and 1 side is filed (50mm x 6mm) and used as the reference side. Then a second side is filed. While using file, force is applied and the file is moved diagonally and in a back and forth motion in order to obtain a uniform surface. A try square is used to check for flatness and right angle. These steps are repeated for all the sides in order to get accurate 900 corners. While having at least 2 horizontal sides (one 900 corner) accurate marking can be done on the marking table. Chalk is rubbed on 1 of the flat surface (50mm x 50 mm) of the workpiece and then the workpiece is aligned with the marking slab of the marking table. Then, using the height gauge and the scriber all the measurements and center lines are marked on the surface which have been rubbed with chalk. The centers of the holes to be drilled are localized and marked out using a center punch. The punch is hit with the hammer with a single and powerful blow. The center pinch is done to prevent slipping during the drilling process. Then the work piece is clamped in a cross slide drill press vice for drilling. A piece of wood is first placed under the work piece to avoid damaging the drill bit after it goes through the metal.. With the power of the drill press still off, the drill is manually lowered slowly until it touches the marked center. The metal piece is positioned on the drill working table in such a way that the drill tip does not slip out of the marked center.A drill bit of 3mm diameter at 850 rpm is used to drill the hole. The machined is turned on and the 3 holes are drilled Using the same diameter and speed, the process is repeated to the two other holes Safety goggles are worn during the machining process because of flying metal chips.

Note: diagrams are not to scale. (Fig 1 to Fig6) Fig 1

Now work piece is brought to another drill press with a drill bit of 8.5mm diameter. Same procedure is followed and two holes are drilled (for the M10, and 15mm radius)

Fig 2

The work piece is brought to third drill press with drill bit of 15mm diameter.Hole is drilled at 270 rpm.

Fig 3

Now, the two diagonal edges are cut. The workpiece is clamped in the bench vice and is cut usint the hacksaw.Sawing might leave a bad quality finish; Filing is done on the 2 edges that have been cut to give a smooth surface.

Fig 4 For the groove, 3 holes of 3mm diameter are drilled on the area to be removed. (3 center punch are done prior to drilling)

Fig 5

The shaped is cut out leaving a small allowance to avoid an oversized groove. Sawing is done along the lengths. Then, using a chisel and a hammer, the undesired part is removed. Then a square file is used to obtain the square shape of the desired dimensions and a smooth finish.

Fig 6

And the last step is to use the M10 tap tool to do the internal threading in the 8.5mm diameter hole. Note: for each complete clockwise revolution of the tap tool , the tool is rotated turn anticlockwise.

Measures taken to avoid any inaccuracies and problems encountered While using file, force is applied and the file is moved diagonally and in a back and forth motion in order to obtain a uniform surface. Before drilling, the centers are localized and marked out using a center punch. This is also done to prevent slipping during the drilling process, which would lead to inaccurate holes and bad quality surface finish. While the power still off, the drill is manually lowered slowly until it touches the marked center of the workpiece. While using the saw, cutting is started slowly in order avoid slipping and also damaging the cutting blade. Also, large force is applied only when pushing to avoid damaging the blade teeth. Also, prior to drilling, the drill bit is aligned accurately to the center of the hole to be drilled and is held firmly in this position. This prevents the workpiece from vibrating during drilling, thus increasing the accuracy. Also, while carrying out the internal threading, oil was used as lubricant and applied.

Safety precautions taken Wear safety googles while drilling Lower speeds are used for drilling larger holes Always ensure that workpiece is firmly clamped before doing any processing

LatheMaterial used: Lathe Drill Bit Parting Tool scriber M10 Tap Tool. Metal ruler and vernier callipers

Operations on lathe: Turning Facing Knurling Grooving Parting Chamfering Taper Turning Drilling Threading

Machine tool used: LATHE

Lathes are employed for turning external cylindrical,tapered, and contour surfaces; boring cylindrical and tapered holes, machining face surfaces, cutting external and internal threads, knurling, centering, drilling, counterboring, countersinking, spot facing and reaming of holes, cutting off, and other operations.

Turning:Machining Process used to produce cylindrical parts. Generally, process consists of material being removed from a rotating workpiece by moving a single-point tool linearly along the length of the workpiece, in a direction parallel to the axis of rotation.

Facing:Facing is the process of removing metal from the end of a workpiece to produce a flat surface. Most often, the workpiece is cylindrical. When a lathe cutting tool removes metal it applies considerable tangential (i.e. lateral or sideways) force to the workpiece. To safely perform a facing operation the end of the workpiece must be positioned close to the jaws of the chuck. The workpiece should not extend more than 2-3 times its diameter from the chuck jaws unless asteady restis used to support the free end.

Parting:Parting uses a blade-like cutting tool plunged directly into the workpiece to cut off the workpiece at a specific length. It is normally used to remove the finished end of a workpiece from the bar stock that is clamped in the chuck.

Chamfering:Chamfering is a process of machining an angled edge(45o) around the end of a cylindrical workpiece.

Drilling: Drilling is the process of using a multi-point tool to penetrate the surface of a workpiece and make a round hole. The alignment between the headstock and tailstock of the lathe enables one to drill holes that are precisely centered in a cylindrical piece of stock.

Workpiece to be manufactured:

The Work piece received was of cylindrical shaped and of approximate length of 80 mm with a 22 mm diameter.

Procedure The work piece is tightened in the 3-jaw chuck in the lathe. To get the work properly centered, the jaws are closed until they just touch the surface of the work, then the work piece being in the jaw is rotated by hand to get in to seat, then the jaw is tightened. A general facing is done to create a flat face perpendicular to the axis of the work piece.(770 rpm) A centre drill is made in the center of the general face work piece by using the tailstock crank to advance the drill(less than 6) slowly into the end of the workpiece and continued until the conical section of the center drill is about 3/4ths of the way into the workpiece. The purpose of the centre drill is just to make a starter hole for the regular drill. A regular 6 mm drill is now used to make a proper drilling to a 20 mm depth in the work piece. A turning process was then carried out in the workpiece reducing its former diameter to 20mm along a length of 60 mm using cutting speed of 770 rpm. Chalk was rubbed on the workpiece to take a measurement of 30 mm with a scriber and the turning process is continued reducing the diameter to 10mm from the 30mm till the 60mm as shown in figure below:

To correct the edge of the work piece and creating a grove having a depth of 3mm, a parting tool of carbide tip is used. A slot of 3mm deep was removed resulting in the work piece shown in the diagram below:

Next, a chamfering process is carried out by turning the tool post set by 45o and cutting was performed at a speed of 550 rpm. The resulting workpiece is as shown in the figure below

The work piece is removed from the chuck and the unwanted part was cut, resulting in the figure shown below:

The last step is to use a M10 Tap Tool for the threading process of the last 30 mm length of the work piece. The tool is aligned perpendicularly with the work piece and is manually threaded. For each complete clockwise revolution of the tap tool, the tool is rotated turn anticlockwise.

Measures taken to avoid any inaccuracies and problems encountered While performing the turning process a low feed was taken in order to have a good surface finish. Drilling was done with great accuracy to prevent a drill of more 20mm to occur. During the turning process for the last 30 mm end, it was made sure for the cutting tool not to touch surface of the larger circular end in order not to damage the cutting tool. It was difficult to chamfer the second end of the work piece, thus a left sided cutting tool was used. Every measurement was taken with great care avoiding zero errors and parallax errors. High feed was taken for a coarse work and low feed was taken for a fine work.

Safety precautions taken Wear safety googles while machining work piece to ensure safety of the eyes Wear a laboratory coat to ensure safety of the body Before adjusting anything, machine must not be performing any operations Always ensure that workpiece is firmly tightened in the chuck before doing any processing