Page 69 - CITS - Fitter Trade Practical - Volume -2

FITTER - CITS

• Mark the center point of rivet holes using a center punch and a setting hammer.
• Drill f 4.2 holes on sheet A and only on the Centre point ‘X’ on sheet ‘B’ by power operated portable hand
drilling machine using a flat wooden piece as support. (Fig 1)

• Place sheet ‘A’ over sheet ‘B’, Insert f 4 x 6 long thinned edge copper rivet in central hole ‘X’ from the bottom
and align the edges of sheet with marked lines for overlap. Place the rivet set on shank of the rivet and strike
over it by a ball peen hammer using a flat steel plate as support. Form the rivet head by a ball peen hammer
using a flat steel plate as support.
• Finish the rivet head so formed, by placing a rivet snap over the rivet and striking with a ball peen hammer.

• While forming the rivet head, ensure that the alignment of the sheet edges and the marked lines for overlap is
not disturbed.
• Drill the remaining holes on the sheet ‘B’, through the holes already drilled on the sheet ‘A’, by power operated
portable drilling machine using a wooden support.
• Deburr the holes with larger sized drill, by rotating it on the drilled holes by hand.
• Insert f 4 thinned edge copper rivets in alternate holes and form the rivet heads in the similar manner.

Layout the spacing for rivet holes (jig-jag seam)

Objectives : At the end of this exercise you shall be able to
• layout the correct spacing of rivets for double riveted (zig-zag) lap joint.

Introduction
The skill is similar to layout the spacing of rivets for double riveted chain lap joint, except the triangular formation
of rivets formed in placement of rivets.
Mark the lines parallel to the edge at a distance of 2d, 3d and 7d.
Mark the points of first rivets from the edges at a distance of 2d and 3.5d and mark further points at a pitch
distance of 3d from the first rivet points. (Fig 1)
Mark similarly on another piece of sheet to be joined

Fig 1

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CITS : C G & M - Fitter - Exercise 64