The Norden Bomb Sight manual

2. First wedge the gyro in the

transverse

plane,

that is, wedge the gyro housing so as to

remove all

a.

Select two thin or siim

wedges for

this

purpose. Wedges should be free of indentat-

ions.

Use the gyro bubbles as a guide. Do not

yet

employ the precision level.

Position the wedges firmly; but this will

be done by

considerable number

of light taps

with a mallet

rather than by a few heavy blows.

5. Use a long slender fiber

drift and

mallet

to tap the gyro housing (if erecting in

the fore

and

aft plane). Again make certain a

considerable

number of light taps are employed

rather than

few heavy blows.

a. This tapping will be done to center

the

gyro bubbles.

6.

Only after

the transverse bubble has been

centered

be made to erect the

gyro in the

and

a.

Wedges for this purpose will be thicker.

b. After this operation is complete, de-

termine whether

transverse bubble is

centered.

7. The precision levei may now be used.

Mount the 3-legged precision table upon

gyro housing.

level

precision

(previously leveled) so that it will give

a reading

for the transverse plane.

b.

Using fiber drift and maliet

, tap gyro

housing

lightly until the bubble of the precision

level is centered.

C.

Check constantly to determine whether

the precision level

is actually level by turning

it 180°

the bubble should occupy the same rela-

tive position in

Turn the precision level 90° so that

it reads in the fore and aft plane. Follow the

same procedure.

Finally turn the precession

level back

90° so that it reads in the

transverse

plane and

check to see that the bubble still remains center-

ed.

J.

Erect Telescope Transverse Cross Hair To The

Vertical.

1. The object is to position the transverse

hair

in relation to the gyro with the

verti-

cal; that is, with the gyro in the vertical and

3.

a

will

the

a.

the

Upon

the

d.