Students enjoy themselves during V.T.

Vernier Caliper: Explained

The vernier caliper is one of the most commonly used measuring instruments in the industry. Let me try & explain how it works.

Fig.1: The Vernier Caliper

Least Count:

Simply put, the least count of a vernier caliper is the minimum measurement one can measure, using that vernier. All the measurements possible on a Vernier Caliper, are multiples of it's Least Count. 

A Vernier with Least Count of 0.05mm (Fig.2) can measure from 0.05mm, and it's multiples, like 0.1mm, 1.15mm, 50.5mm etc.

Fig.2 

A Vernier with Least Count of 0.02mm (Fig.3) can measure from 0.02mm, and it's multiples, like 0.12mm, 6.18mm, 45.5mm etc.

Fig.3

Main Scale:

The Main Scale on a Vernier Caliper is the fixed scale (refer Fig.1). It's very important to know the value of a Main Scale Graduation. Figs.4 & 5 show one main scale graduation.

Fig.4

Fig.5

Vernier Scale:

The Vernier Scale on a Vernier Caliper is the sliding scale (refer Fig.1). One Vernier Scale Graduation (Figs.6 & 7) is a fraction of One(or n) Main Scale Graduation (it is also equal to the difference between one(or n) Main Scale Graduation & the Least Count). 
Example. 1 (refer Figs.4 & 6):
1 Main Scale Graduation(M) = 1mm
1 Vernier Scale Graduation(V) = 0.95mm
Least Count(LC) = 0.05mm
M - LC = VC

Fig.6

Example. 2 (refer Figs.5 & 7):

1 Main Scale Graduation(M) = 0.025 inches
1 Vernier Scale Graduation(V) = 0.049 inches
Least Count(LC) = 0.001 inches
2(M) - LC = VC

Fig.7

Calculating Least Count:

The Least Count of a Vernier Caliper is not necessarily marked/written on every Vernier Caliper. The user should know how to find out the Least Count, which also helps in understanding the principal behind the Vernier Caliper.

Fig.8

Careful observations of Fig.8 reveals that 20 Vernier Scale Graduations(V) equal 19 Main Scale Graduations(M). Let's call the No. of Vernier Scale Graduations, n.
nV = (n-1)M
nV = nM - M
V = M - M/n
V = 1 - 1/20 (since M = 1 mm)
V = 1 - 0.05
V = 0.95 mm

Least Count(LC) = M - V
LC = 1 - 0.95
LC = 0.05 mm

The Least Count can also simply be calculated as:
LC = M/n
LC = 1/20
LC = 0.05 mm

Fig.9

The Least Count for the Vernier Caliper in Fig.9 (Inches) can simply be calculated as:
LC = M/n
LC = 0.025/25
LC = 0.001 Inches

Working of the Vernier Caliper:

A movement equal to the Least Count or it's multiple, of the Vernier Scale, results in alignment of a Main Scale & a Vernier Scale graduation, which gives the measurement.

Vernier Caliper Animated:

I've tried to show how the consecutive vernier scale graduations align with the consecutive main scale graduations, after each movement of the least count.

I hope this article was helpful. Let me know if you would like me to come up with an article on a topic which interests you.

Comments and/or suggestions are most welcome. 

Cherished Moments from V.T. 19 Dec 2015 - 02 Jan 2016. One week of fun

Vocational Training at Chandra Engineers. 19 Dec 2015 - 02 Jan 2016, Day 7, 25 Dec 2015

Vocational Training at Chandra Engineers. 19 Dec 2015 - 02 Jan 2016, Day 5, 23 Dec 2015.

Vocational Training at Chandra Engineers. 19 Dec 2015 - 02 Jan 2016. Day 4, 23 Dec 2015

Vocational Training at Chandra Engineers. 19 Dec 2015 - 02 Jan 2016, Day 3, 22 Dec 2015

Nexus 6P Unboxing (in HINDI)

Featured Daily Activity Log. Vocational Training 19 Dec' 2015 - 02 Jan' 2016.

The trainees at Chandra Engineers are encouraged to write a "Daily Activity Log", after class, of the activities of the day. 

I appreciate the efforts of all the trainees who have sent me their DAL's. 

There are two entries which I would like to share(in no specific order), as follows:

Pratap Paul's D.A.L. & Sumanta Pradhan's D.A.L

Will be sharing in the future as well. Hopefully this is a motivating factor for the trainees.

Vocational Training at Chandra Engineers. 19 Dec 2015 - 02 Jan 2016, Day 2

Vocational Training at Chandra Engineers. 19 Dec 15 - 02 Jan 16, Day 1, ...

Vocational Training at Chandra Engineers. 14 to 26 Dec 2015, Day 5, 19 Dec 2015. The Universal Milling Machine

Vocational Training at Chandra Engineers. 14 to 26 Dec 2015, Day 4, 18 Dec' 2015. The Shaper Machine

V. T. Session 19 Dec 2015 - 02 Jan 2016. NHIT 2nd Year Students

Dear 2nd Yr NHIT Students,

Please fill in the e-Form

V. T. Session 19 Dec 2015 - 02 Jan 2016. Meet the Trainees

I thought it's a good idea to let everyone meet the students

V. T. Session 19 Dec 2015 - 02 Jan 2016. Pre-Class Notes.

Dear Students,

Great having you all as trainees for the V. T. Session 19 Dec 2105 - 02 Jan 2016. 

I appreciate the efforts of the following students, who emailed me their Day 1 activity log:

1. Prasun Banerjee
2. Pratap Paul
3. Rick Nayak
4. Sumanta Pradhan
5. Dinendu Banerjee
6. Sabnam Dasgupta

See you all in the class.

Abhinav. 

Vocational Training Session 19 Dec 2015 to 02 Jan 2016.

Dear NHIT Vocational Trainees,

This gives me pleasure to welcome you to a fresh session of Vocational Training at Chandra Engineers, starting 19 Dec' 2015.

There are certain mandatory requirements, some need to be sorted out during the orientation session, other will be a daily affair. The same are listed below:

1. Fill in the Student's Detail form, link to be uploaded soon. Update (20 Dec 2015) link to the form added. 

2. Collect your free gift, a 12" Steel Ruler, from your course co-ordinator & bring it along everyday.

3. Submit a photocopy of the Student's I.D. Card, provided by your Institute.

4. Safety shoes are a must, in the workshop. Safety will not be compromised upon. 

5. Having a gmail account in mandatory, create one if you don't have one.

6. Writing a "Daily Activity Log" is a mandatory requirement as well. User Google Docs for this purpose, instead of wasting paper (let's save the trees). Email your daily log to abhinavsg@gmail.com. This will help you prepare your final Training Report.

7. Include images in your Daily Activity Log, of the operations/activities you performed in the workshop. Use your mobile phone to take images.

Enjoy learning new skills. I am sure it's going to a fun fortnight.

Good Luck,

Abhinav Gupta

Vernier Caliper, Imperial cum Metric

The Vernier Caliper is one of the most commonly used measuring instruments in industry. Lets have a look at one, which measures, both in the Imperial as well as the Metric systems. The parts and the use have been marked for it's study.

Posts coming soon: 

• The Vernier Caliper explained 
• How to read the measurements on a Vernier Caliper

Update, 31 Dec 2015: The Vernier Caliper explained

Vocational Training at Chandra Engineers. 14 to 26 Dec 2015, Day 3, 16 Dec 2015. Operating the Planer Machine

Day 3, 16 Dec' 2015 was dedicated to the Planer Machine. The trainees learned to operate the machine. They got hands-on, following the instructions of the instructor. Have a look at the action, in the video.

Vocational Training at Chandra Engineers. New V. T. Session starts 19 Dec 2015, for Second Year NHIT Students

Dear NHIT Students,

Vocational Training for the Second Year students will start on 19 Dec 2015 upto 02 Jan 2016 ( 15 working days )

Interested candidates may contact 9475155555 or abhinavsg@gmail.com or comment to this post.

Vocational Training at Chandra Engineers. 14 to 26 Dec 2015, Day 2, 16 Dec 2015. Welding & Planer Machine set up

Day 2 was action packed. The trainees got hands on with welding and Planer Machine. Watch the short video to catch a glimpse of the happenings.

Manufacturing Drawing of Shaft

Dear Trainees,

I am posting the manufacturing drawing of the Shaft, we will be working on, as part of the training for Turning & Boring Section. We will doing the rough turning of the Shaft, leaving 40 Thousand's all around, for the final machining.

Make sure everyone has a print of the drawing.

Vocational Training at Chandra Engineers. 14 to 26 Dec 2015, Day 1, 14 Dec 2015. About V.T. & Measurements.

A brief video, summarizing the activities on day 1, 14 Dec 2015, of the Vocational Training Session 14 - 26 Dec 2015

How To : Install a PTFE ( Teflon ) Piston Ring on a Piston

As promised in an earlier post, the PTFE Piston Ring Installation video is now up on youtube.

Enjoy

Vocational Training Session 14 Dec 2015 to 26 Dec 2015

Dear NHIT Vocational Trainees,

This gives me pleasure to welcome you to a fresh session of Vocational Training at Chandra Engineers, starting 14 Dec' 2015.

There are certain mandatory requirements, some need to be sorted out during the orientation session, other will be a daily affair. The same are listed below:

1. Fill in the Student's Detail form, linked here.

2. Collect your free gift, a 12" Steel Ruler, from your course co-ordinator & bring it along everyday.

3. Submit a photocopy of the Student's I.D. Card, provided by your Institute.

4. Safety shoes are a must, in the workshop. Safety will not be compromised upon. 

5. Having a gmail account in mandatory, create one if you don't have one.

6. Writing a "Daily Activity Log" is a mandatory requirement as well. User Google Docs for this purpose, instead of wasting paper (let's save the trees). Email your daily log to abhinavsg@gmail.com. This will help you prepare your final Training Report.

7. Include images in your Daily Activity Log, of the operations/activities you performed in the workshop. Use your mobile phone to take images.

Enjoy learning new skills. I am sure it's going to a fun fortnight.

Good Luck,

Abhinav Gupta

Multiple Mailboxes in the Yahoo Mail app - Now with Gmail

Multiple mailboxes on Yahoo Mail App. Gmail, AOL & Outlook accounts can now be added along with Yahoo Mail, in the Yahoo Mail App. Even the desktop Yahoo Mail shows all your accounts. This is pretty convenient.

How to: Install a PTFE (Teflon) Piston Ring on a Piston

Recently we got an order from an old & loyal client of ours, for a Piston. The Piston was for a Rexroth Hydraulic Cylinder. The used Piston was handed over to us as a sample for manufacturing a new one. I am posting it's picture, below:

We manufactured the Piston & ordered the Rubber "O" Ring (which works as a seat for the Teflon Piston Ring) as well as the Teflon Piston Ring. In addition to this we manufactured an Expanding Mandrel and a Resizing Tool to aid proper installation of the Teflon Seal. Picture attached below:

The most tricky part was to install the Teflon Piston Ring. I searched the internet for installations procedure. I found a few articles (one of the article is attached below) written about it but couldn't find an installation video or actual installation pictures. I shot a video during the installation, which will be posted on my YouTube Channel shortly. 

Update (14 Dec 2015): Installation Video

Vocational Training Details

This is a small video which briefly describes the Vocational Training at Chandra Engineers.

Hook forging, manual process

I uploaded a video on youtube, showing the Hot Bending of a Carbon Steel Hook, which is a custom made part for one of our clients. We use a Screw Jack for the process. Comments & suggestions welcome.

Vocational Training Report

Dear readers,

This is a Vocational Training Report, submitted by an ex-trainee. Thought it will be useful for future trainees & students.

Presentation on Vocational Training

Hello readers,

Some ex-trainees made a presentation on the vocational training, they took at Chandra Engineers, at their institute.
This gives me pleasure to share the link to the Presentation on Vocationl Training. The same will definitely help the future trainees as well as other students who look for material on the web.

How to: Measure in inches on a 12 inch ruler

Vocational Training Details

Vocational Training 2015-16

CHANDRA ENGINEERS

Dear students, welcome to a fresh session, 2015-16, of Vocational Training at Chandra Engineers, Durgapur.

About Chandra Engineers:

Chandra Engineers, located right on N. H. 2, Bhiringi, Durgapur, W.B. INDIA, was established in 1958, by founder father, Lt. Sri Mahesh Chandra Gupta, a Post-Graduate in Mech. Engineering from the prestigious Banaras Hindu University. Currently run by Sri. Sunil Gupta, M.D. & CEO who himself is a Post-Graduate in Mech. Engineering (Machine Design) from IT BHU & Sri. Abhinav Gupta, COO, an Engineering Graduate in Information & Communication Sciences from Macquarie University, Sydney.

The organization has facilities for Machining, Fabrication, Light Forging, Design and Training. The primary activities include manufacturing of custom made spares & components for heavy industry, mainly Steel, Fertilizer & Plastic. Execution of Turn-Key Projects, which involve design, manufacturing, supply, installation, erection & commissioning. Providing industry based Apprentice & Vocational Training to Graduate as well as Student Trainees, helping them perform well in job interviews & adapt quickly & easily to the industry, which employs them.

List of Facilities:

Ø Machining Facility:

o   Turning & Boring Section:

§  Engine Lathes

§  Semi-Norton Lathes

§  Norton Lathes

§  Horizontal Boring Machine, Table Type

o   Shaping & Plaining Section:

§  26” Stroke Shaping Machine

§  8’ Bed Plaining Machine

§  6’ Bed Plaining Machine

o   Drilling & Milling Section:

§  Pillar Type Drilling Machines

§  Radial Drilling Machines

§  Magnetic Base Drilling Machines with Taping capabilities

§  Precision Drilling Machine, table type, for very small drill holes

§  Power Tapping arrangement for all drilling machines

§  Universal Horizontal Milling Machine

§  Vertical Milling Machine

Ø Fabrication, Metal Forming & Smithy Facility:

o   Welding & Gas Cutting:

§  A.C. Output Welding Transformers

§  D.C. Output Welding Rectifiers

§  MIG MAG Welding Machine

§  Gas Welding & Brazing

§  Oxy-Acetylene Gas Cutting

o   Smithy & Metal Forming:

§  Bending Rolls

§  Bending Knifes

§  Screw Jacks

§  Ball Press

§  Punching Press

§  Pit Furnace, adequate for light forging.

o   Marking, Fitting & Fabrication:

§  Punching Press

§  Base Plates

§  Various Tri-Squares, Dividers, Jigs & Fixtures

§  Various Angle Grinders of different sizes

§  Various Straight Grinders of different sizes

§  Various Flexible Shaft Grinders of different sizes

§  Various hand tools

Ø Design, Testing & Heat Treatment &Finishing Facility:

o   Dell Optiplex Workstations – 2 Nos

o   Non-Branded Workstation – 01 No

o   Dell & Sony Mobile Workstations – 01 No each

o   Solid Works CAD software

o   Solid Edge CAD software

o   Autocad CAD software

o   Hydraulic Pressure Testing equipment

o   In-Situ Stress Relieving facility

o   Flame Hardening facility

o   Phosphating facility

Ø Measuring Instruments:

o   Various Micrometers, metric as well as imperial

o   Various Vernier Calipers

o   Various Inside Diameter Micrometers

o   Various Dial Indicators

o   Level checking instruments

o   Angle Protractors

o   Various OD & ID Calipers

o   Various Steel Rules

o   Various Measuring Tapes

What is the Vocational Training all about?

The vocational training at Chandra Engineers is structured, very well thought out and conducted in an organized manner. The emphasis is on skill development, related to workshop technology, efficient management of paper work & documentation in real life industrial environment and overall personality development. These skills help trainees perform well in job interview, which have a proven track record, as well as learn & adapt quickly to the industry, they work in. We cover the following points:

Ø Development of practical skills with the help of hands on training, which includes Machining & Fabrication.

Ø Theoretical discussions & presentations on various topics, viz: Steel Making, AC & DC Drives, Heat Treatment, Strength of Materials.

Ø Writing Daily Activity Log, which helps trainees prepare Vocational Training Report & develops writing skills

Ø Regular use of internet, email, social networks & blogs, keeping in mind digitization of paper work & tendering process in industry. The trainees get a good real life feel of the way industry works in this day and age.

Ø Trainees are involved in Group discussions related to the training, which helps in overall personality development & overcome inhibitions in facing interviews.

Hands-On Training:

Ø Turning & Boring Section

o   Parts of the Lathe & Boring Machine

o   Mounting the workpiece, on 4 Jaw independent Dog Chuck on a Lathe & Table on Boring Machine

o   Centering the workpiece with the help of Marking Block/Surface Gauge

o   Performing various operations on the Lathe & Boring Machine

o   Achieving the desired dimensions as per drawing

o   Gear calculations pertaining to Threading

Ø Shaping & Plaining Section

o   Parts of the Shaping & Plaining Machine

o   Mounting the workpiece on the machine

o   Performing various operations on the shaping & plaining machines

o   Achieving desired dimensions as per drawing

o   Detailed explanation of the quick return mechanism for the idle stroke in shaping & plaining machines

Ø Milling & Drilling Section

o   Parts of the Milling & Drilling Machines

o   Proper marking of the workpiece before Milling & Drilling

o   Mounting the workpiece on the Milling & Drilling Machines

o   Detailed explanation of how an Indexing Head works & calculations pertaining to it

o   Performing various operations on the Milling & Drilling Machines

o   Tapping as well as using power tapping attachment on Drilling Machines

o   Achieving desired dimensions as per drawing.

Ø Welding & Gas Cutting

o   Introduction to Welding Transformers, Rectifiers & MIG MAG Welding Machines

o   Various weld joints & positions

o   Setting current for different weld joints & positions

o   Gas welding & Brazing

o   Oxy-Acetylene Gas Cutting

Ø Marking & Fitting

o   Reading fabrication drawings

o   Drawing Lay-Outs as per drawings

o   Fitting on the drawn lay-outs

o   Development of tubular & conical structures & intersections

Ø Smithy & Metal-Forming

o   Forging

o   Hot & Cold bending & metal forming

o   Use of Ball Press, Knife Bending Machine, Bending Rolls, Screw Jacks & Punching Press

Ø Measurements & Measuring Instruments

o   Introduction to Imperial System of Measurements

o   Reading measurements on Steel Ruler, Vernier Calipers & Micrometers

o   Practically using various measuring instruments during the course of training while performing machining as well as fabrication operations.

Contact abhinavsg@gmail.com for joining Vocational Training & Apprentice Training Courses at Chandra Engineers, Durgapur, W.B. INDIA.