I have encountered a problem while rebuilding the "layshaft"
(intermediate pulley between the motor and spindle) on my 
Deckel GK-12 3D pantograph engraver.  It has S/N 4500-1958.
A photo is shown in 
GK-12-Layshaft-Photo-2.jpg

It has 3 grooves and looks more or less like the one shown
on this manual pag:
GK-12-Layshaft-3-Gruv.jpg

Other GK-12 manuals show a 4-groove version:
GK-12-Layshaft-4-Gruv.jpg

Here is a cutaway of the 4-groove version:  
GK-12-Layshaft-4-Gruv-X-Section.jpg

Note the snap-ring at position "A".  On my 3-groove, the 
snap-ring is at position "B".  This does not seem right 
because there is no spacer between the outer races of the 
two bearings, so tightening the nut at the bottom crowds
the two races together.  If you just try to snug it with-
out crowding the bearings, there is nothing to keep the
nut from unscrewing, and it doesn't take much to do that.

Does anyone have a cross-section of the 3-groove layshaft?
Wrench, does your CD have this version?

It seems like there either needs to be a spacer between the
outer races, or better yet, the snap ring groove should be
relocated to "A" so the lower bearing is clamped and the
upper bearing can float.  (I think the bearings are close
enough together that it will be OK if the upper bearing
does not float, provided the inner race and outer race spa-
cers are the same length.)  The inner races are both a snug 
press fit and are clamped with a spacer between them, so
they are not going anywhere.