Head Segments

Page 59

Head Segments

Dims Required: OD OC Segment length (1/4

Circumference), segment width, number of

segments.

Calculating a Segment Width

Set a straight edge on the side of the head to

determine the maximum width that can

be used without deflecting on the sides.

Divide this measurement into the OC to get the

number of lags (peels) required.

Adjust this number up or down to get a number

that is easily divided by 4.

Redivide this number of segments into the

circumference to get the actual segment

width.

Quick Method:

Divide the OC by 24, 28, 30, 32, 36 or 40. This will

give you the seg width.

Mathematical Method: (Special Only)

Draw the side view of the head (1/4

circumference)

Divide the 1/4 arc into equally spaced parts and

label.

Draw lines from the center line 90° through the

arch @ each of the divisions & measure

each line to the arc.

Use the segment width formula on R1-7 to

determine division widths (seg width X

R1 –7 ÷ R1).

Head Segments: Stretch-out:

Cut a piece of metal 1/4 of the OC + Bottom lap.

Layout the segment length & divide into the same

# of parts as the working drawing &

label. Add a center line.

Mark 1/2 the measurements on each side of the

center line. Formula: Seg Width X R1-7 ÷

R1 = S #s Example: 16mm X R330mm ÷ 35

mm = 13.71 mm

Add Lap as required and use as a pattern.

Head Segments (Chalk line method)

Mark a centerline on the head from tip to edge.

Mark 1/2 the segment width on each side of the

center line.

Place a chalk line on seg width lines and extend to

head tip & snap a line.

Divide the center line into equally spaced parts

and measure the seg width @ each of

these divisions.

Lay out the seg length (1/4 OC) & divide into the

same # of divisions as the head center

line.

Transfer the measurements form the head to the

stretch-out, add laps and process.

Head Segments:

See width X R1 –7 ÷ R1= Seg Widths