I had to restring the dial on a French Oceanic radio recently. They use a very tight dial cord. I could not get the cord that tight and the cord slipped on the pulley attached to the tuning shaft. However, 2 coats of "Phono non slip" by GC Chemical on the pulley fixed most of the slippage problem. This stuff is hard to find these days.

Any remaining slippage can be stopped by treating the dial cord with violin bow rosin, available from any music store or Amazon.

Before starting be sure to remove any oils or lubricant from the face of the pulleys if there is any.

The fix is actually stringing the dial cord correctly with the proper cord and making sure everything is free and lubricated properly. I have never had a problem when done this way. They never left the factory with "mouse milk" on the cord.

Dave

Dave is right.
Every slipping cord was fixed by proper tension on clean wheels and properly lubricated pulleys.

Before I understood to do that I too tried several things that helped like bees wax.. or scraping some wax off old paper/wax caps and using that on the cord. Also, Bill Turner sold me a bottle of liquid rosin.

But lubricating pulleys, cleaning and making sure all surfaces are smooth does the trick.

It goes without saying that the proper dial cord, and a new spring of the correct size, and correct routing of the cord are a must.

This radio is a little different. Two different cords are wound side by side on the same drum but go to different places.

Also the tuning knob shaft has a pulley that is concave. This is not just the usual "wrapped around the shaft" kind of arrangement. If you are familiar with driven belts you know this will tend to throw off whatever is wrapped around it because the outside edges of the pulley will have a faster rotational speed than the smaller radius inside part of the pulley. Consequently these cords must be quite tight or they will slip or move off the pulley. Lubricate the axle of the pulley, yes, but take care not to get any on the path of the cord over the pulley.

The tips I mentioned might be of use to someone in the same situation. I could not get the belt tight enough so I resorted to these hacks.

A tip I learned from Stan at one of the SCARS classes - a strip of fiberglass high temperature electrical tape on the pully.

That concave shaft is made such that the dial cord can ride up and slide back down to the center again as it moves along. That concave area MUST be smooth and clean.
If it's dirty or has garbage on it.. the cord will sometimes lap over itself and get stuck on itself right there.
Clean clean .. and shiny works.

Clean, lube, and new cord are the key items. Old worn cord may still slip.

RRM

Always fresh clean cord, right off the spool!

Hard to find dial cord, ebay sellers are selling fishing line most of which is the wrong diameter, the wrong material, and lubricated with graphite and silicone.

Dave

I didn't know that... I thought it was basically the same stuff.

I also bought a spool from Bill Turner a few years back... I'm sure that stuff is genuine. But it looks just like that black nylon woven fishing line.

I use what is called ice fishing line or tip up line. It is braided, comes in different sizes and can be nylon or dacron, nylon has more stretch and is slippery. Some of these braided lines are teflon coated and you don't want that. Most casting line is coated with some type of lubricant to make them cast better, so stay away from any casting line.

Dave

Nice Tip

source for dial cord:

https://www.amazon.com/Dial-6138-Vintag ... =dial+cord

Radio Daze sells it in both .040 and .030 gauge

http://www.radiodaze.com/search.php?sea ... =dial+cord

Adams Manufacturing sells .062 diameter dial cord for those that need a thicker cord.

Yes, they sell the dial cord in 3 diameters by the foot. Here's the link ( scroll to lower section of the page):
http://www.adamsradio.com/page2.html

rub a candle on the cord everywhere you can get it. The wax actually increases the grip. Also, I have 'dial cord dressing' from the old days. its like candle wax with a little pumice in it.
Mark Oppat

I got a Marconi 296 set a while back. It's a fairly big old set with two different dial scales with the needles moving in opposite directions as you adjust the frequency (see photo 1). The dial string was broken, but apparently original (see photo 2). When I found service instructions for the set it actually specified a particular twenty-something pound braided British fishing line, and it uses something like 8 or 9 feet of it! Apparently you need heavy duty dial string to haul in those big British stations!




Bob

Dial stringing may be difficult for some folks. The self-righteous comment "proper parts, proper procedures, never left the factory with "mouse milk" on the dial cord is of little help to someone with diminished eyesight or dexterity in the fingers. One man's hack my be another man's salvation. Many old radio repair books I have read have mentioned the rosin trick for slipping dial cords.

You are so right! Eyes are going, fingers just aren't nimble as they once were. And to top it off, the knot for the loop must be tied in 1/4 inch x 1 inch gap between the variable cap and the pulley. Extremely difficult. And there are 2 separate cords on the same pulley! That Marconi is a piece of cake by comparison!