Belt slippage on an accordion?

[boxplayer4000]

This is not an accordion related request for information but I have noticed, over the years, that there are many informed inputs to our sites with technical knowledge over a wide range of issues so I hope all will be patient with my request.

I grew up in a farming environment and have always felt privileged to have done so and was exposed early to ‘nature’ and technical matters as well as farming was going from labour intensive to more modern methods. Repairs and maintenance was largely done ‘in-house’ where possible. (By ‘nature’ I mean that by an early age we had worked out how the ‘birds and bees’ worked and were ahead of the game when the subject was tackled in school).

The point I’m getting towards is canvas drive belts. Many machines, such as threshing machines, bruisers, circular saws etc. were driven by a power take-off (PTO) on a tractor. The belt pulley surfaces were not flat, as I remember, but convex and this assisted in keeping the belt from jumping off. The belt ends were held together by two steel ‘combs’ which were hammered into the canvas and the two halves of the comb were joined together with a steel pin.

At last my point:- There was some skill in positioning the tractor so that best alignment and belt tension was achieved. To minimise or eliminate slippage a substance was ‘painted’ onto the belts inner surface and was tacky and stiff as I remember.

So the question is: What was that substance?

There is guidance online but no mention of a specific substance and most of the sites veer towards a sale of their product.

I have no access to tractors or associated machinery those days but I have a record deck which handles 33/45/78 rpm discs which sometimes misbehaves, I suspect. I have renewed the drive belt but felt that a means of reducing slippage might be helpful.

I am aware that the drive belt is not canvas; probably a plastic or polymer which might not re-act well to some anti-slip substances.

I have a paper disc which lies on the record deck, with a printed pattern, which re-acts to our power supply frequency of 50 hz. When the speed is correct the pattern is ’stationary’. I use a microscope attached to the computer to get a good picture of the record needle.

 

[John Doe]

There used to be a resin dissolved in alcohol paint on that was used on phono idler wheels as well as tape deck drive wheels et al. Usually it was a last resort when the changing mechanism (driven off the platter shaft with nylon/pot metal gears) would stall because the force required caused the idler to lose traction and spin helplessly. The stuff sometimes worked though the root cause was usally stiff/dried out lube in the changer mechanism.

Once it got to the point where the actual platter rotation was affected by slippage curing play you were pretty much sunk as a rule.

My juke box has slippage issues from the idler coped with largely by really careful cleaning. The part is, of course, no longer made and I'm reluctant to send off the existing idler to be rerubbered. Of course the tracking force on most juke boxes is pretty hign.

On belt drive turntables there is usually not a machanism driven off the platter (usually, not always) and the belt is generally lightly dusted with talc just so that it can slightly slip on start up. Rather than trying to make the beld sticky as in a car/tractor drive belt I'd go for a new belt and carefully clean the pulley whee on the motor shaft as well as the platter where the belt rides. You'd be making the start up a bit herky jerky- but makers have cope with that through pulley design over the years and it's probably be fine.

Unless you use a heavy dust bug or have a Rabco 4 like set up where something is retarding the platter the only real friction comes from the stylus- assuming your platter spins freely. Take off the belt and then spin the platter with you hand- it should take a long time to slow down.

As a last resort you might go with a new belt slightly smaller (length, not width). There are a lot of turntable belts available on the internet and replacing a belt is very simple. That's "slightly smaller/tighter". You don't want to add a significant lateral load to the pulley or upper motor shaft bearings or to the platter bearings for that matter.

Good luck!