This document describes the fabrication and machining process for manufacturing a turnbuckle. It involves turning, drilling, boring, and threading steel rods to create the main body and threaded ends of the turnbuckle. Specific steps include reducing the diameter of rods, cutting threads on each end, drilling holes, and assembling the turnbuckle components. Precautions for use and estimated manufacturing costs are also provided.

1. FABRICATION & MACHINING OF TURN
BUCKLE
BY
ADITTYA CHAKRABORTY
UNDER THE GUIDANCE OF
SUDIPTA GHOSH(SUR)
A PROJECT REPORT
Submitted In Partial Fulfillment of the Requirements
For The Diploma In
Mechanical Engineering
DEPARTMENT OF MECHANICAL ENGINEERING
KINGSTON POLYTECHNIC COLLEGE, BERUNANPUKURIA, P.O- MALIKAPUR,
BARASAT, 24 PGS (N), KOLKATA - 700126

4.  To know the viability of manufacturing
machining of turnbuckle
 To know how to manufacture turnbuckle
 To know the fabrication process of turnbuckle
 To know the precautions for the
manufacturing of turnbuckle

5.  SOURAV DUTTA
 VASWATI SAHA
 INDRAJIT SENGUPTA
 ADITTYA CHAKRABORTY
 ANKAN ACHARYA
 SAMANNWAY SENGUPTA
 KOUSHIK ROY
 BAPON MONDAL
 SUBHAMOY NASKAR
 KARTICK CHANDRA PATRA

6.  Turnbuckles are most commonly used in applications which
require a great deal of tension; they can range in mass from
about ten grams for thin cable used in a garden fence, to
thousands of kilograms for structural elements in buildings
and suspension bridges
 Turnbuckles are used for tensioning a ship’s rigging and
lashings. This device is also known as a bottle screw in this
context.

7.  They are widely used in aircraft, on flexible cables in flight
control systems. They are secured with lock wire or
specifically designed wire clips to prevent them from turning
and losing tension.
 Another application of this instrument is in shipping; here
they are used for tensioning a ship’s rigging and lashings.
This device is also known as bottle screw in this context.
 Turnbuckles also find a popular use for tensioning the
ropes in professional wrestling rings and boxing rings,
where they serve as the attachment between the ring
ropes and ring posts. The turnbuckles come into
particular play in professional wrestling where they are
often put to use by participants as part of their
offensive repertoire.

8. Turnbuckle with eyes

10.  A turnbuckle, stretching screw or bottle screw is a device for
adjusting the tension or length of ropes, cables, tie rods, and
other tensioning systems. It normally consists of two
threaded eye bolts, one with a left hand thread and the other
with a right hand thread. The tension can be adjusted by
rotating the frame, which causes both eye bolts to be screwed
in or out simultaneously, without twisting the eye bolts or
attached cables.
 A metal coupling device consisting of an oblong piece
internally threaded at both ends into which the
corresponding sections of two threaded rods are
screwed in order to form a unit that can be adjusted for
tension or length.

11.  A device for tightening a rod or wire rope. Its parts are a sleeve
with a screwed connection at one end and a swivel at the other
or, more commonly, a sleeve with screwed connections of
opposite hands (left and right) at each end so that by turning
the sleeve, the connected parts will be drawn together, taking
up slack and producing tension (see illustration). Types of
ends are hook, eye, and clevis. The turn-buckle can be
connected at any convenient place in the rod or rope, and
several may be used in series if required.

13.  Applying 3mm feed to remove the outer layer of metal in
order to decrease the diameter from 44mm to 32mm as per
diagram by turning process. This is done on two 44 diameter
rods, i.e. 2 small rods.

14.  Now threading was done on these 2 small 32 mm
jobs up to 72mm in length. A right hand thread
and a left hand thread were done on these 2 jobs.
At the end of 72 mm we created a depression of
5mm diameter as well
 Using turning we also remove the outer layer of the
 Now we drill a hole by using 27 drill bit and 28
bore bit. While drilling we reduce the speed of the
lathe but while boring we increase the speed of the
lathe

15.  . A 55mm thread is done on both sides of the
big job.

16.  After creating a hole with 55 mm threads, we created a sort
of uplift on the big job, by lathe machine.

17.  Now we applied a hex poll on either sides of the job of 32
mm each of 1 inches

18.  Using suitable lubricant we check the fitting of the
turnbuckle.
 The making of a simple turnbuckle is successful and ready for
industrial use.

19.  Turnbuckles may be used for straight or in-line pulling only.
Special attention should be paid to prevent overloading. While
tensioning, the forces on the turnbuckle must not be such
that any deformation occurs. In case of deformation, the
tension should be decreased immediately and deformed parts
should be replaced.
 It is required that the products are regularly inspected and
that the inspection should take place in accordance with the
safety standards given in the country of use. This is required
because the products in use may be affected by wear, misuse,
overloading etc. with a consequence of deformation and
alteration of the steel structure

20.  Cost of 14kg of EN8 STEEL @Rs. 47/kg……Rs 660
 Metal cutting charges…………………Rs 150
 Cost of Turning, Drilling, Boring, Thread cutting &
Tapping(4-5 hours operation)……………..Rs. 1000
 Grinding……………………………Rs. 300
 Overheads like electricity, labour cost,….Rs 1000
 Total manufacturing cost………Rs. 3110

21.  The threads of the body and the end fittings are of the same
type
 The threads of the body and the end fittings are undamaged
 The body and the end fittings are not distorted or unduly
worn
 The body and end fittings are free from nicks, gouges and
cracks.