Dial String Slippage Tonic: Elmer's Spray Adhesive

Pbpix · **Posted:** May Fri 25, 2012 7:46 pm

R. Jepsen wrote:

Pbpix wrote:

I have suggested the use of rosin or bee's wax in a previous post.. but ...
...Actually if the pulleys are properly lubricated on their shafts and moving freely and if the pointer is also not restricted AND if the main pulley is clean and smooth with no rust where the cord rides ... there should be no need for any tacky stuff on the cord.
The small drive shaft is often made such that it has a v-shaped or valley-shaped depression where the cord rides. This is where the cord is usually wrapped around 2-1/2 or 3 times.
That groove MUST be shiny and smooth as the cord needs to slide up and down the valley to prevent it from overlapping itself on long travel or reverse travel.
With proper tension on the slack-tensioning spring and ALL smooth freely moving wheels and shafts there should not really ever be a need for rosin or such.
Yes rosin can help if the cord is stretched or to get past a problem of drag... but it is not the total, proper answer... only a patch so to speak.
If you have patience and you can actually get the cord on "right" with all wheels free and smooth surfaced...it will not need anything else.

I have spoken ... lol

You speak well and I have done exactly as you outline. I might add that it is extremely important to check the tuning capacitor rubber mounts. As they decay and turn to coal dust, the dial cord tension will pull up on the large pulley throwing the assembly out of alignment. View the tuning capacitor from the end of the chassis and check to be sure it is sitting perpendicular to the top of the chassis. Grasp the tuning capacitor and see if it is solidly mounted or rocks. On the typical RCA chassis, grommets (OD.5625 ID.2500) can be used to replace the original rubbers. Before attempting to push them into the three chassis holes, first heat with a blow dryer or hot water to make them pliable. When hot, two-thirds of the grommet can be pushed into it's hole and the remainder using a small screwdriver blade. Also, use finger on opposite side to pull edge of grommet into position.

Yes.. rotting grommets will cause the tuner to rock or wobble throwing off the cord alignment.
So I also regularly inspect and replace the grommets. A box of various sizes can be purchased through Harbor Freight or elsewhere for only a few bucks.
http://www.mcmelectronics.com/product/2 ... =526356402
I have never needed to heat them to get them in. Sometimes I have to manipulate them a bit, but they fit with a little force.

R. Jepsen · **Posted:** May Fri 25, 2012 10:25 pm

Re: I have never needed to heat them to get them in. Sometimes I have to manipulate them a bit, but they fit with a little force.

===============================================

The grommets in my hoard are made of Neoprene and kind of tough at room temperature.

http://www.phillipsind.com/product/118.html

R. Jepsen · **Posted:** May Sun 27, 2012 6:50 pm

As an added note to the slippage topic, I was lubricating the pulleys & TC and inadvertently got some sewing machine oil on the dial cord. The extent of any added slippage is unknown but holding the end of a wax capacitor against the cord while transversing the scale took care of the problem. The bees wax idea is without a doubt sheer genius.

This was a chassis where some Bloke attempted to fix the slippage problem by adding an extra turn to the tuning shaft and mulafustring the spring. This, of course, caused secondary problems and so the radio was cast onto the junk pile of time to accumulate dust and dirt. Luckily it reached my hands rather than the landfill. Amazing what a few grommets, oil, and wax can do.

codefox · **Joined:** Nov Sat 27, 2010 6:15 pm **Posts:** 3601

As we all know, "All repairs are temporary." Great information!

Tom Sanders · **Joined:** Jan Sat 07, 2012 5:32 am **Posts:** 18

If beeswax or the wax from a old capacitor will work, what about a piece of wax broken from a burned-out candle?

Beaconhunter · **Posted:** Feb Sun 10, 2013 3:56 am

Tom, the wax used then and now are 2 different beasts. Additionally, old caps have been cooked in radios and after decades of exposure to the air, the wax can be fairly gooey.

I have used wax candles to lubricate wooden sash windows that were sticking, which is the opposite of using old tacky wax to prevent cord slippage.

John S.

OZ132HOME · **Posted:** May Mon 06, 2013 6:46 pm

Well over 8 years on the ZTO Using Elmer's Spray Adhesive.
Only used it because the ZTO is a bear to dissassemble.
I'd say it works pretty fair...

Dial String Slippage Tonic: Elmer's Spray Adhesive

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