[Hallicrafters] Dial Cord -- Slip No More Forever

[Ron Evans]

Greetings, Halli-gang

Well, the restringing of the bandspread capacitor on my S-85 is 
accomplished, and I just have to share a technique I blundered onto that 
may come in handy for you sometime.  Many of you will have your own 
particular technique, and I'm hoping you will share it with the list.

First, I have to say that unless you "pre-stretch" the dial cord from 
AES, you can be in trouble, depending on the receiver you are working 
on. Their catalog proudly states that their cord is, "a no-stretch black 
cord made of nylon over a fiberglass core." Black...yes.  Nylon...yes. 
Fiberglass core...yes.  But "no-stretch"?? No cigar!  It does stretch 
even under the moderate tension imposed by properly stringing a dial cord.

I discovered this on my maiden voyage, restringing a Hallicrafters 
S-38D.  Everything worked perfectly immediately after the repair.  But 
the next morning -- total failure.  The cord had stretched overnight. 
You could turn the bandspread knob forever, but the cord would slip 
hopelessly on one of the small idler shafts.  You have a pretty good 
idea which one or ones may give you trouble if the restringing 
instructions prescribe going around the shaft...say 3 1/2 or 4 turns.

I removed the cord and begin thinking how I could increase the friction 
between the cord and the idler shaft.  Luckily, the idea that first came 
to me worked perfectly and is still working after three years.  I took 
an ordinary gummed label and cut a strip as wide as the area the string 
would traverse and long enough to go completely around the shaft.  (I 
also had sanded the label lightly with very fine sandpaper to rough it 
up a little.)  I wrapped the label, gummed side down, around the shaft, 
installed the line cord again, and celebrated my victory!

Since that time I have found something that works even better.  I take a 
piece of masking tape, coat it with rubber cement, and allow it to dry. 
  Then I wrap the tape around the shaft as before.  No slipping!  You 
can do this on as many shafts as the cord traverses.  It won't hurt if 
the tape goes around the shaft more than 360 degrees, but I wouldn't 
build up too much tape.  The string has the happy effect of applying 
pressure on the tape, keeping it in place even if the tape should dry 
out in time.

Works for me!  What other methods have you hit upon that keep dial cord 
from slipping if it begins to stretch?  The little spring on the large 
pulley is supposed to do that job but rarely does it, in my limited 
experience.  I've heard that one can apply rosin to the cord to keep it 
from slipping also, but I haven't tried it yet.

So, what tips or techniques can you share?


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