DAILY DIARY

WORKSHOP: Machine ShopGROUP MEMBERS: 12102029- Mukesh Kwatra12102068- Aditya Aggarwal12102070- Viresh Verma12102083- Agam Sachdeva12102084- Rajit Mehan WORKSHOP COMMENCED: 28th May 2013WORKSHOP ENDED: 19th June 2013JOB: Multiple operations on a workpiece.

DAY-1 On the first day we were allotted our workshops. Our group was allotted the machine shop. After the allotment process got over, we went to the shop. We interacted with other groups as well as with the instructors. We were briefed about the work in the shop and advised to be sincere, disciplined and punctual.DAY-2 On the second day, we were provided with the sketch of the job to be made and we were all required to have a copy of the sketch. The sketch was complete in all respects and all the operations to be performed were highlighted. The operations were mentioned in order. The estimated time required to perform each operation was also mentioned.Each group was required to make three jobs. We cut out three pieces of length 175mm and diameter 36mm from a long rod of mild steel. This was done with the help of Power Hacksaw. Power Hacksaw is used to cut metals in large size, something which is not possible manually. The blade of the Power Hacksaw is made of High Speed Steel (HSS). The machine works on a hydraulic mechanism. We also poured coolant on the blades to avoid damage to the blade due to prolonged heating due to the cutting of metal.After this, we started with the facing of the cut out pieces. Facing was done on lathe machine with the help of single point cutting tool. For this purpose, the job is held in a three-jaw chuck or centring chuck. As the name suggests, this holds the job exactly in centre. For proper facing, the tool is taken from inside to the outside.DAY-3 On the third day, we continued with the facing of the jobs. We also performed drilling and counter-sunking on both the faces of the jobs. This is required to hold the job properly in head stock and tail stock.We were also explained the step turning process.

DAY-4 For the step turning process, firstly marks were made on the job with the help of a chalk and pen to highlight the distinction between different diameters. After this, we started with the step turning process. The job is first fixed in the job holder with the help of bench vice. Step turning is done with a single point cutting tool which is moved from right to left and job rotates anticlockwise.

DAY-5 On this day we continued with the step turning process.DAY-6 We continued with the step turning process on the three jobs. By the end of this day, we were finished with step turning operation.DAY-7 Due to one-sided cutting, the boundary between two different diameters is tapered. On this day, this taper was removed and edges were straightened with the help of edge straightening tool. We were also introduced to the milling machine and explained about the milling operation. We were told about the various parts of the milling machine-arm arbour, indexing plate, bracket and also about different cutters like involutes cutter, slab mill cutter, angular cutter etc.

DAY-8We did hexagonal milling. In this we use slab mill cutter made of HSS is used which is of helical shape. We did indexing by applying the formula 40/N were N is the number of sides required. As in this case N = 6. So the ratio 40/N becomes 6(2/3). This requires us to rotate the hand wheel 6 times and additional 2/3 turns. We compute 2/3 holes in the following manner:We multiply and divide by 7 to make 21 in the denominator so the resultant becomes 14/21. This takes us to the conclusion that we have to rotate additional 14 holes to complete the remaining 2/3 turns since in total the circle in which we were rotating in the indexing plate had 21 holes.During the milling operation, water in the form of coolant was continuously supplied to counter the heat produced due to metal cutting.We were explained about the knurling and taper turning processes.

DAY-9We continued with the milling process. It was a lengthy process and it took about three quarters of an hour to complete one job.Side by side, we also began with the knurling process.For the knurling process, knurling tool is fitted in the lathe machine, job is rotated counter-clockwise and the tool is hard-pressed against the job to produce a criss-cross pattern. The tool is moved both in forward and backwards direction to produce the correct pattern.

DAY- 10Today we continued with the milling and knurling processes and these operations were done with. Next we moved to the taper turning process. First of all, we calculated the taper angle. The formula for this is:Tan A=(D-d)/2lSubstituting the values,D=25mmd=20mml=20mmWe found the angle is 7 degrees approximately.We rotated the dial to 7 degree and started taper turning.In this carriage wheel is not rotated.Cross feed and compound wheel is rotated.We were also explained about the V-shaped threading process, to be done at 6TPI.

DAY- 11 Today we did square threading on the job. We were taught by our instructors about different typex of threading like V-shaped threaing whose tool angle is 55 degree, acme threads whose tool angle is 29 degree etc. After threading we did filing on our job to give it smooth finishing. TPI of this thread is 6 , so the depth of the cut as calculated by the formulaDepth of cut = 1/(TPI X diameter)Which gives us 2 mm, so the depth of cut is 2 mm.Coolant was poured continuously to avoid damge to the job and tool due to over-heating.

DAY- 12Today we did V-shaped threading on the job. To accomplish this job, orthogonal tool was used . The TPI required for square threading was 10, so the depth of the cut using above formula is 4.18 mm. We used coolant to avoid damage to our job and tool due to over heating . In this case also filing was done to give smooth finishing.

DAY- 13 After finishing square threading, we moved on to drilling and parting off of the hexagonal part of our job. To accomplish this we held the job in the 3-jaw chuck. The drill of mearurment 16.5 mm was used which was held still while our workpiece was rotated. Coolant was poured to reduce heat at the tool job interfrace and thus acted as a coolant. Drill was taken inside up to the sleeve part. After this, parting was done to using a tool similar to square threading tool. Clearance is kept double the width of the tool to avoid the stucking of the tool. After this facing was done with the help of facing tool to give finishing.

DAY-14On this day we performed internal threading operation on the parted hexagonal part with the help of tap. The job was held horizontally in the bench vice. After this tap was inserted in the drilled hole while the tap was held using tap holder. The tap was first rotated clockwise for a few turns and then turned anticlockwise so that the generated chips may fall. All through this procedure, lubricant oil was applied to the tap for the smooth movement of the tap and generation of threads.DAY-15On this day, first of all the knurled part of the job was drilled using a 16.5mm diameter drill. Following this, the knurled part was parted off from the job. During the course of drilling and parting off, constant coolant supply was provided for. To enlarge the diameter to 18mm, boring tool was used. The tool, moved with the help of compound rest, was moved through the knurled part so that uniform diameter on both the ends could be obtained. For internal tapering, dial on the tool post was set to 7. The boring tool was moved forward with the help of compound rest wheel throughout the job to obtain taper on the internal side.DAY-16On this day, we did the facing of the job to produce better surface finish of the ends of the job. This was done on the lathe machine.Day-17On this day, we rubbed emery paper on the jobs to remove the rust and to give a fine shiny appearance to the jobs. Due to application of water as a coolant rust had settled on the job.To accomplish this, first of all machine oil was applied on the jobs and emery paper was rub on it.