First progress report on a multi-channel magnetic drum inner ...

IX-;
A study of L/rawing C-5-2013 v.ill reveal in detail the construction
of the drum, •''he revolving drum consists of twelve parts, •'•'he drum
itself is a piece of drawn brass tubing with an outside diameter of $
inches, a wall thickness uf 1/8 of an inch and a length of 12-5/8
inches. The druir. is fastened to its shaft by means of a pair of
aluirlnum end bells and two central aluninum expanding support disks.
Aluminum spacers separate the end bells and expanding support disks.
Nuts on the shaft ends exert a force on the inner races of the ball
bearings, '^lis force is transferred through large aluminum, thrust washers
to the end bells and also from the end bells through the alumdnum spacers
to the central expanding support disks
.
The end bells have been turned from 2 inch aluminum plate. Each end
bell contacts the drawn brass drum tube in two places as shown. The inner
contact area is a l/4 inch annular flat face on the end bell. There is a
press fit between this face and the drum tube. The outer contact area is
a tapered 1/4 inch annular face on the end bell. This end bell taper ends
in a 1/8 inch shoulder. In assemibly the end bells are pressed into the
tube until the tube ends hit the tapers. Then the shaft nuts are turned
and the bells are forced farther into the drum until the tube ends seat
home on the 1/8 inch shoulders of the bells. Thus there is a wedge fit
between the drum and the bells along the outer edges of the drum.
An examination of the central expanding support disks in Drawing C-5-2013
shows that their inner faces are concave or dish-shaned. These disks