Eccentric Reducer or Hognose

Page 118

Eccentric Reducer or

Hognose

Information Required: OD of large

insulation, OD of small insulation, length of

fitting

Step 1: Draw an elevation view and

establish an apex by drawing lines from

both outside diameter lines to a point. This

point is the apex.

Step 2: Draw a half-circle on top of the

elevation, trisect and label.

Step 3: Using pint 1 as a temporary apex,

swing arcs from all the numbered points of

the semi-circle to points on the horizontal

line of the large diameter fitting. Label

these points from A-G as shown.

Step 4: Draw lines from these points to the

original apex point.

Step 5: Establish point G for the stretch-out

and swing arcs from points F, E, D, C, B and

A using the original apex as your swing

point.

Step 6: Set the dividers from 1 to 2 on the

semi-circle and take this set to point G and

mark a point on line F. Continue this

walkout and step down one letter each time

until you reach line A, then step one line at

a time until you reach line G.

Step 7: Measure the slant heights of each

lettered line and transfer these

measurements to the corresponding

lettered lines.

Step 8: Connect all the lettered and slant

height points to form the fitting.

Step 9: Add for crimp and lap allowance

where necessary.