ABSTRACT

      In this project it is based on the need for the work holding devices. This design

and fabrication which will enable the operation like drilling, reaming, tapping process

easier. This project is mainly composed of “DESIGN AND FABRICATION OF THE

ANGLE PLATE JIG” which cover the absolute design to the specified dimensions of

the work piece. This angle plate jig is economical means to produce

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1. INTRODUCTION

1.1 INTRODUCTION

Mass production aims at high productivity to reduce unit cost and interchange ability

to facilitate easy assembly. This necessitates production devices to increase the rate

of manufacture and inspection device to speed-up inspection Procedure.

Jigs are special purpose tools which are used to facilitate production like machining,

assembling and inspection operations. The mass production of work-piece is base

on the concept of interchange ability according to which every part produced within

an established tolerance. Jigs provide a means of manufacturing interchangeable

parts since they establish a relation with predetermined tolerances, between the

work and the cutting tool. Once the jig is properly set up, any number of duplicate

parts may be readily produced without additional set up.

Jigs are used on drilling, reaming, tapping, milling and tapping. There are many

Advantages for using jigs in production. Jigs eliminate individual making, positioning

and frequent checking. This reduces operation time and increase productivity. There

is no need for selective assembly.

1.2 OBJECTIVES  

i. This jig has built in accuracy, the precision positional relationship b/w jig

bushes in different planes are passed on work piece.

ii. Jig is a source which holds the job strongly and also guides the tool.

iii. It eliminates the need for marking on the job.

iv. These are light weight these can be used either by fastening them with the  

table or holding them in hands.

v. Even an unskilled technician can use them with these features, we sincerely

hope that our project serve as a valuable project. We welcome the correction,

comments based on our project.

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2. LITERATURE REVIEW

2.1 INTRODUCTION

This chapter discussed about literature review of jigs designing for the angular

cylindrical part. It begins with introduction to the jigs, type of jigs and components in

the jigs. Furthermore, the advantages and disadvantages of the jigs were discussed

and the important of the jig design were discussed briefly.

2.2 INTRODUCTION TO JIGS

Mass production aims at high productivity to reduce unit cost, and

interchangeablities to facilitate easy assembly. This production device increases the

rate of manufacturing and inspection devices to speed up inspection procedure.

Jigs are specially provided for mass production. Jigs provide a means of

manufacturing interchangeable parts since they establish a relation, with

predetermined tolerances, between work and cutting tool. So, they eliminate the

necessity of a special set up for each individual part thereby reducing the cost. So,

jigs are generally used

i. To reduce the cost of the production.

ii. To assure high accuracy of parts.

iii. To increase the production.

iv. To save labour cost.

v. To value quality control expense.

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Some of the basic requirements of a good drill jigs are:

i. Quick and accurate location of the work piece.

ii. Easy loading and unloading of the work piece and prevention of wrong

loading.

iii. Prevention of bending or movement of the work piece during drilling.

iv. Ample chip clearance which facilitates for swarf removal and cleaning.

v. Light weight to minimize operator fatigue due to repeated handling.

Figure 2.1: jig

In the shop, drill jigs are the most-widely used form of jig. Drill jigs are used for

drilling, tapping, reaming, chamfering, counter-boring, countersinking, and similar

operations.

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2.2.1 Elements in Jigs

Figure 2.2: Elements in Jigs

i. Jig body

ii. Jig feet

iii. Jig bushing

iv. Jig plate or bush plate

v. Locators

vi. Clamps

vii. Fool proof element

i. Jig body

The jig body supports the work piece and has locating and clamping elements in

it. It is provided with four jig feets and rests on the machine table.

ii. Jig feet

a jig feet which is not bolted to machine table is provided with four jig feet,

instead of the entire bottom surface lying flat on the machine table. Jig feet are either

cast with the jig body or detachable or welded to the base. They are usually

hardened and ground to have flat bottom.

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iii. Jig bushing

For guiding drills, reamers and boring bars, hardened steel jig bushes are

employed which are fixed in the jig plates. The bushes can be replaced when worn-

out with less cost than replacing the entire jig plate.

iv. Jig plate or bush plate

Usually the jig plate carries the jig bush for guiding the tools. The jig plate may

be rigidly constructed as a single unit of jig or it may be of leaf or latch type. In this

type, the jig plate must be clamped with the jig frame.

v. Locators

Locators help a work piece to ret in proper position in a jig. Depending on the

type of work piece, various types of locators are used for the locating the

components, in the jig with reference to the tools, the locators are usually detachable

type, fixed to the jig frame. So whenever wear occurs, the locators can be easily

replaced with new ones.

vi. Clamps

Clamps are used for holding the work piece rigidly against all disturbing forces.

They also keep the work piece firmly in contact with locating pins of surfaces.

Sufficient thickness of section should be provided to withstand clamping forces.

vii. Fool proof element

This element prevents the work from being loaded wrongly into the jig. The

elements may be simple fouling pegs, cross pieces or pins.

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2.3 IMPORTANT OF JIGS

Jigs are very important in manufacturing industry. These tools needed to make

sure that manufacturing process in production line going smooth and easier to

operator doing their job. Jig helps operator to holding part which will be processing or

in operation. In production rate, using jigs increased the productivity because it will

minimize the production time.

2.3.1 Advantages

i. Productivity

Jigs eliminate individual marking, positioning and frequent checking. This

reduces operation time and increases productivity.

ii. Interchange ability

Jigs facilitate uniform quality in manufacture. There is no need for selective

assembly. Any part of the machine would fit properly in assembly, and all

similar components are interchangeable.

iii. Skill reduction

Jigs simplify locating and clamping of the work-pieces. Tool guiding elements

ensure correct positioning of the tools with respect to the work pieces. There

is no need for skilful setting of the work-piece or tool. Any average person can

be trained to use jigs. The replacement of a skilled workman with unskilled

labour can effect substantial saving in labour cost.

iv. Cost reduction

Higher production, reduction in scrap, easy assembly and savings in labour

costs result in substantial reduction in the cost of work-pieces produced with

jigs.

2.3.2 Disadvantages

In industry, using jigs is very important in operation. Nowadays, tool is more

important than workman skill. This will make the industrial lacking skilful man in

workplace. When the tool is breakdown, the production rate will be decrease. Cost

for maintenance will be higher.

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2.4 TYPES OF JIGS

Jigs mainly divided in to two types

1. Boring jigs

2. Drill jigs

1. Boring jig

Figure 2.3: Boring Jig

In machining, boring is the process of enlarging a hole that has already

been drilled, by means of a single-point cutting tool or of a boring head containing

several such tools, for example as in boring a gun barrel or an engine cylinder.

Boring is used to achieve greater accuracy of the diameter of a hole, and can be

used to cut a tapered hole.

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2. Drill Jig

Figure 2.4: Drill Jig

Drill jigs are used to drill, ream, tap, chamfer, counter bore, counter sink, reverse

spot face, or reverse counter sink. The basic jig is almost the same for either

machining operation. The only difference is in the size of the bushings used.

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2.4.1 Types of Drill Jigs

Drill jigs may be divided into two general types

1. Open jig

2. Closed jig

Open jigs are for simple operations where work is done on only one side of the

part. Closed, or box, jigs are used for parts that must be machined on more than one

side. Drill jigs are designed and constructed based on structure work piece. Some

type’s jigs listed below

1. Template Jig

2. Plate Jig

3. Sandwich Jig

4. Latch or Leaf Jig

5. Channel Jig

6. Box Jig

7. Post jigs

8. Angle plate Jig

9. Angular post Jig

10.Turnover jig or Table type Jig

11. Pot Jig

12. Solid Jig

13. Trunnion Jig

14. Indexing Jig

15. Universal Jig or Pump Jig

16. Multi Station Jig

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I. Template Jig

Figure 2.5: Template Jig

This is a simple plate of metal or wood which carries correct locations of holes to

be made in the work piece. Size of template jig should be same as that of the work

piece. It is overlapped with the work piece and drilling is done quickly. Use of this

jig avoids the marking operation completely.

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II. Plate Jig

Figure 2.6: Plate Jig

Plate jigs are similar to templates jigs. The only difference is that plate jigs have built-in clamps to hold the work. These jigs can also be made with or without bushings, depending on the number of parts to be made.

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3. Sandwich Jig

Figure 2.7: Sandwich Jig

The sandwich jig is almost similar to plate jig. The only difference is the backup

plate found on the sandwich jig. This back up plate allows the jig to hold very thin

parts that could bend or distort under tool pressure. The sandwich jig can also be

used as a combination jig in which one side of the tool is used to locate the part for

drilling. The opposite side is used for reaming or tapping the part.

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4. Latch or Leaf Jig

Figure 2.8: Latch or Leaf Jig

Leaf jig is also called as latch jig. This type of jig is distinguished by its hinged

cover, a leaf which can swing open to load or unload the work piece. After the work

piece has been located inside the jig, the leaf is firmly closed and locked inside the

jig. The leaf is held on to the jig body with the help of an eyebolt where the eye is

hinged to the body with a pin and a nut on the threaded portion of the bolt tightens

the leaf. The drill bushes are fitted in the leaf.

Leaf jigs can be loaded and unloaded quickly and are suitable for complicate

work pieces with irregular contours. The disadvantage of leaf jigs is that chips may

accumulate inside and cause trouble unless provisions are made for disposing them.

Also, if the drill bushings are fitted in the leaf, play in the hinges may affect drilling

accuracy.

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5. Channel Jig

Channel jigs are the simplest form of box jig. The work is held between two

sides and machined from the third side. In some cases, where jig feet are used, the

work can be machined on three sides.

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6. Box Jig

Figure 2.11: Box Jig

Box jigs, or tumble jigs, usually totally surround the part. This style of jig allows

the part to be completely machined on every surface without the need to reposition

the work in the jig. Channel jigs are the simplest form of box jig. The work is held

between two sides and machined from the third side. In some cases, where jig feet

are used, the work can be machined on three sides.

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7. Post Jig

Vertical

Figure 2.12: Post Jig Vertical

Horizontal

Figure 2.13: Post Jig Horizontal

The post jig is used to locate the drill plate. The swing washer enables the drill

plate to be removed without removing the hand nut. The post jig is also used for

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drilling and reaming, a ‘C’ washer is used to obviate the need to remove the hand

nut.

8. Angle Plate Jig

Figure 2.14: Angle Plate Jig

Angle-plate jigs are used to hold parts that are machined at right angles to their

mounting locators. Pulleys, collars, and gears are some of the parts that use this

type of jig.

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9. Angular Post Jig

Figure 2.15: Angular Post Jig

Angle-plate jig, which is used for machining angles other than 90 degrees.

Figure shows an angular post jig of welded construction. The drill bush is extended

and shaped to prevent drill run, and yet allow removal of work piece. The clamping

nut is of the quick-action type because the smallness of the work piece bore

demands that the nut be removed when the work piece is removed.

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10. Turnover Jig or Table Type Jig

Figure 2.16: Turnover Jig or Table Type Jig

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Plate jigs are sometimes made with legs to raise the jig off the table for large

work. This style is called a table jig.

11. Pot Jig

Work Piece

Figure 2.17: Pot Jig

Pot jig body is in the form of a pot in which the work piece is supported and

clamped. Circular work pieces which have both an external diameter and an internal

diameter suitable for location purposes are drilled in pot type jigs. The jig essentially

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consists of two parts. The body which is in the form of a pot carries the work piece

and also the bush plate.

Figure illustrate a pot jig in which the work piece is located from its outside in

the bush, and the drill bush is located on a post; the drill plate is located to line up

with swarf clearance grooves.

12. Solid Jig

Figure 2.18: Solid Jig

The figure shows a solid jig that is made from a block of steel. The work piece

is clamped by a button clamp, and burr groves are provided so that the work piece

can be easily recovered. Two grooves are required because one burr will be

produced at the point of drill entry, and a second burr is produced at the point of drill

break through.

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13. Trunnion Jig

Figure 2.19: Trunnion Jig

A trunnion jig is similar to a box jig. When a large sized work piece is to be

drilled in several faces, it is mounted in a trunnion jig so that the faces requiring

drilling operations can be turned easily and positioned. Every time, the jig is rotated

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and it is locked so that the face in which the hole is to be drilled is absolutely

horizontal. The pin and the locating hole for locking the jig should be wear resistant.

14. Indexing Jig

Figure 2.20

Indexing jigs are used to accurately space holes or other machined areas

around a part. To do this, the jig uses either the part itself or a reference plate and a

plunger. Larger indexing jigs are called rotary jigs.

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15.Universal Jig or Pump Jig

Figure 2.21: Universal Jig or Pump Jig

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Pump jigs are commercially made jigs that must be adapted by the user. The

lever-activated plate makes this tool very fast to load and unload. Since the tool is

already made and only needs to be modified, a great deal of time is saved by using

this jig.

16.Multi Station Jig

Figure 2.22: Multi Station Jig

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Multi station jigs feature is how it locates the work. While one part is drilled,

another can be reamed and a third counter bored. The final station is used for

unloading the finished parts and loading fresh parts. This jig is commonly used on

multiple-spindle machines. It could also work on single-spindle models. There are

several other jigs that are combinations of the types described. These complex jigs

are often so specialized that they cannot be classified. Regardless of the jig

selected, it must suit the part, perform the operation accurately, and be simple and

safe to operate.

2.5 Materials

Jigs are made of variety of materials, some of which can be hardened to

resist wear.

2.5.1 Materials generally used

i. High speed Steel

Cutting tools like drills, reamers and milling cutters.

ii. Die steels

Used for press tools, contain 1% carbon, 0.5 to 1% tungsten and less

quantity of silicon and manganese.

iii. Carbon steels

Used for standard cutting tools.

iv. Collet steels

Spring steels containing 1% carbon, 0.5% manganese and less of silicon.

v. Non shrinking tool steels:

High carbon or high chromium Very little distortion during heat treatment.

Used widely for fine, intricate press tools.

vi. Nickel chrome steels

Used for gears.

vii. High tensile steels

Used for fasteners like high tensile screws

viii. Mild steel

Used in most part of Jigs and Fixtures

Cheapest material

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Contains less than 0.3% carbon

ix. Cast Iron

Used for odd shapes to some machining and laborious fabrication

CI usage requires a pattern for casting

Contains more than 2% carbon

Can withstand vibrations and suitable for base

x. Nylon and Fiber

Used for soft lining for clamps to damage to work piece due to clamping

pressure

xi. Phosphor bronze

Used for nuts as have high tensile strength

Used for nuts of the lead screw

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3. DESIGN AND FABRICATION

3.1 Components of Angular Post Jig

Plunger pin

Drill bush

Index plate

Quick-action nut

Angular plate

Jig base plate

Jig top plate

Jig vertical plate

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3.2 Construction

The angular post jig construction is vertical plate is welded in the base plate.

Top plate is welded in the vertical plate. The one end of the angular plate is welded

in the base plate then other end is welded in the top plate. Angular plate used for

supported the work piece. Index plate is fitted upper surface of the angular plate with

the help of plunger pin. Quick-action nut is used for locking and also supporting the

work piece. Drill bushes are fitted in top plate according to the work piece.

Figure 3.1: Angular Post Jig

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3.3 Part drawing

FRONT VIEW SIDE VIEW

TOP VIEW ISOMETRIC VIEW

Figure 3.2: Pictorial View of Angular Post Jig

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3.4 Working Principle

Angle-plate jig, which is used for machining angles other than 90 degrees. The

angular post jig of welded construction. The drill bush is extended and shaped to

prevent drill run, and yet allow removal of work piece. The clamping nut is of the

quick-action type because the smallness of the work piece bore demands that the

nut be removed when the work piece is removed.

3.5 Advantages

Produce high accuracy of parts

Save labour cost

Quick and accurate location of work piece

Easy loading and unloading

Mass production

Reduce the cost of production

3.6 Applications

Mass production industries

Angular component manufacturing

3.7 Bill of Material

S. No Part Name Material Quantity

1 Base plate M.S. 1

2 Vertical plate M.S. 1

3 Top plate M.S. 1

4 Angular plate M.S. 1

5 Bush M.S. 1

6 Index plate M.S. 1

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Table 3.1: Bill of Material

3.8 Essential Features of Jigs

i. Reduction of idle time

Should enable easy clamping and unloading such that idle time is minimum.

ii. Cleanliness of machining process

Design must be such that not much time is wasted in cleaning of scarfs,

burrs, chips etc.

iii. Replaceable part or standardization

The locating and supporting surfaces as far as possible should be

replaceable, should be standardized so that their interchangeable manufacture

is possible.

iv. Provision for coolant

Provision should be there so that the tool is cooled and the swarfs and chips

are washed away.

v. Hardened surfaces

All locating and supporting surfaces should be hardened materials as far as

conditions permit so that they are not quickly worn out and accuracy is retained

for a long time.

vi. Inserts and pads

Should always be riveted to those faces of the clamps which will come in

contact with finished surfaces of the work piece so that they are not spoilt.

vii. Fool-proofing

Pins and other devices of simple nature incorporated in such a position that

they will always spoil the placement of the component or hinder the fitting of the

cutting tool until the latter are in correct pos.

viii. Economic soundness

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Equipment should be economically sound; cost of design and manufacture

should be in proportion to the quantity and price of producer.

ix. Easy manipulation

It should be as light in weight as possible and easy to handle so that

workman is not subjected to fatigue, should be provided with adequate lift aids.

x. Initial location

Should be ensured that work piece is not located on more than 3 points in

anyone plane test to avoid rocking, spring loading should be done.

xi. Position of clamps

Clamping should occur directly above the points supporting the work

piece to avoid distortion and springing.

xii. Clearance

Sufficient amount of clearance should be provided around the work so

that operator’s hands can easily enter the body for placing the work piece and

any variations of work can be accommodated.

xiii. Ejecting devices

Proper ejecting devices should be incorporated in the body to push the

work piece out after operation.

xiv. Rigidity and stability

It should remain perfectly rigid and stable during operation. Provision

should be made for proper positioning and rigidly holding the jigs and fixtures.

xv. Safety

The design should assure perfect safety of the operator.

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CONCLUSION

The project work has provided us an excellent opportunity and experience to

use our limited knowledge. We gained a lot of practical knowledge regarding

planning, purchasing, assembling and machining while doing this project work.

We feel that the project work is good solution to bridge the gates between

institution and industries.

We are proud that we have completed the work in limited time successfully.

The “Design and Fabrication of Angular Post Jig” is working with

satisfactory conditions. We are able to understand the difficulties in maintaining

tolerance. We have to done to our ability and skill making maximum use of

available facilities.

In conclusion remarks of our project work, let us add a few more lines about our

impression project work. We feel very proud in submitting this report to our

institution.

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REFERENCE

Jigs and fixtures, press tools – C. Elanchezhilan and B. Vijaya Ramnath

www.jigsand fixtures.com

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