[R-390] How are your knobs ?

[Pete Williams]

​.. G'dsy..... in the process of restoring/rejuvenating 390s'over the years
. I've been blessed on   few occasions with broken fingers on the  kHz and
Mhz  knobs
To get proper functioning  and  everything looking right, I got me  a tame
machinist./turner  with lathe  and  such.
I don't  know if this has been  documented on this  list but the procedure
and   work done was  as follows .

.!.. The inside of the  knob where the fingers  and web meet  at the
shaft 5/16" (0..312) hole is  drilled out to about 0.55"and down to the
bottom of the shaft hole.

2.  A  brass insert was turned up 0.95 " long  with OD of 0.55" for  a
snug fit in the  drilled hole . The ID of this insert is same  as shaft
diameter 0,312. and has a wall thickness of  about 0.12".

3. The insert is held in place with a coating of metal adhesive--- one of
the  cyanoacrylate  type  and  I was assured this will  never let go.....
and never has  either.

4. two holes  were  drilled on the  outer lip of the  knob  and holes
drilled into the brass insert  of  appropriate   diameter to b e tapped
and take the usual Bristo  set  screw. These holes  were  set 90 degrees
apart to  prove for   ample  holding ability. The length of the protruding
insert from the hole is  about 0.4 "--- approx. same as the length of the
4 fingers from the  web.. Set screw holes positions  located as in original,
Has worked well with no problems.....
I've taken some close up pics of the knob  and  can email off to any
interested.

Pete VK3IZ