slide based on metal stitching

1. PRESENTED BY
ADITHYA S KOTIAN
(7353107010)
Metal Stitching

2. CONTENT
 DEFINITION
 INTRODUCTION
 WORKING PROCEDURE
 TYPES OF EQUIPMENT REPAIRED USING METAL STITCHING
 TYPES OF PINS USED IN METAL STITCHING
 ADVANTAGE

3. DEFINITION
 Metal stitching or metal locking is a method of
repairing cracks in cast metals without the need of
welding. Cold repairs on all cracked or broken
components made from cast iron cast steel or
aluminium. Breakages usually occur because of
overloading, accidents, equipment misuse or flaws
in the casting.

4. INTRODUCTION
 Metal stitching is the process where cracks caused in the
metal objects are repaired.
 Metal stitching is founded by Gary J Reed in 1990
under his company LOCK-N-STICH inc.
 Metal stitching process uses a series of locks and pins. A
pin is threaded bolt which can provide a pushing or a
pulling pressure to a centre of the pin.
 The pins are bolted down in a series along the crack
then ground down to a smooth surface then the another
layer of pins are bolted down between the gaps of the
pervious pins to provide smooth surface.

5. WORKING PROCEDURE IN METAL
STITCHING
 Using a drill jig, rows of blind holes are drilled
perpendicular to the direction of the crack, each row to
act as a key.
 The intermediate partitions are removed with
pneumatic chisel.
 Metal lock keys are driven into the opening and
caulked.
 Holes for Metal lock screws are drilled along the crack
between the keys.
 The screws are fitted to ensure they overlap, effecting a
seal along the fracture.
 Finally, the entire installation is caulked to ensure
stability and pressure tightness.

7. TYPES OF PINS USED IN METAL
STITCHING.
 The two different types of pins used in metal
stitching are L-series and C-series pin.
 They come with several diameter and thread lengths.
 L and C series pins are used based on there different
types of applications.

8. L-SERIES PINS
 When an L series pin is tightened into the casting they
seal on the threads because of the pin is larger than the
tapered hole. The result of that is a spreading of pressure
around the crack.
 It is very important that there is enough structural
integrity or else there may be a spreading of the crack.
 The design of the L series pins allows an easy installation
at steep angles to the surface.
 The sturdy combustion chambers of cylinder heads allow
the optimum structural strength.

9. C-SERIES PINS
 The C series pin will not cause any spread in a crack.
 Their spiral hook threads create a pressure that
draws in the sides of the crack together permanently
locking them together by exerting a pressure.
 When the shoulder of the pin interacts with the
casting it hooks the sides upwards pulling them in
with a radial drawing force on the cast iron.
 Also cracks that are formed on the corner of the cap
fit in any main bearing should be repaired with C
series pins.

10. TYPES OF EQUIPMENTS REPAIRED USING
METAL STITCHING.
 Cast Iron Repairs.
 Marine Propeller Hub Repair & Cavitations Damage.
 Line Boring.
 Steam turbine & turbine repair.
 Large diesel engine repairs.
 Crankshaft repair and straightening.
 Press bed regrinding.

13. WHY METAL STITCHING IS USED ?
 Metal stitching process is widely used in marine
application.
 When there is a risk in removing the larger marine
equipments the metal stitching is used.
 Due to some of the under water welding is not possible
so metal stitching is used.

14. ADVANTAGES
 Cold repair can be carried out to castings of cast iron,
steel and non ferrous alloys.
 Many repairs can be carried out onsite with minimal or
no dismantling.
 Downtime of equipment is minimized as the broken
pieces can be put together to maintain alignment.
 A pressure tight seal can be achieved due to the
interlocking between Metal lock keys and studding.
 Since the repair is done in a cold state, there is no
distortion and residual stresses are not introduced.
 The original surfaces can be obtained with little or no
machining requirement.

15. REFERENCES
 Wikipedia
 Metalock.co.uk/company website
 Locknstitch.com
 Practiclemantance.net

16. THANK YOU