Thorens portable repair questions

[Mr Grumpy]

Hello forum members,

I am working on a Thorens portable gramophone, specifically the no526 motor.

My problem is with a small spring wrapped around the winding shaft that I suppose is meant to stop the winding handle from turning in reverse.
I've never repaired a machine with this type of spring, so am not familiar with proper nomenclature or even how this spring is supposed to work. The one on the machine is broken but it appears to have originally wrapped around a small screw to prevent it from turning. I've attached a photo of a spring that I've made based on what I think it should look like. However, my new spring doesn't create enough energy to allow me to remove the cranking handle once the machine is wound.

Is this what the original spring might have looked like? Should the other end of the spring be attached to something else?


Any help would be greatly appreciated.

[JerryVan]

Vince,

How tightly does the spring grip the shaft? I don't mean when it's supposed to be holding back the spring tension, I mean when you're cranking, and the "clutch" action is released. It's got to be a fairly snug fit, or it won't engage with the shaft firmly enough to wrap itself tightly around the winding shaft when reversed. You should almost have to unwind the spring a bit to get it over the shaft. As far as what you've made, it looks great and "correct".

I have a fair supply of new-old-stock springs like this. If you could supply shaft dimensions, spring length, etc., I may have one for you.

[Sidewinder]

It is a "non return spring" that as you mention, prevents the winder from unwinding. As to which way it should go, without a picture of one similar it could be trial & error. chances are 50-50. I could send you a photo from a Thorens motor, but due to travel, it could be only in about 2 weeks

I'm not sure a home made one would work unless you are a spring making professional!

[mrrgstuff]

I'm not sure a home made one would work unless you are a spring making professional!

I think I got lucky, but I did manage to make a new non return spring for a Garrard motor. Certainly is possible to do at home: https://youtu.be/6yn4ah9bkNg

[Mr Grumpy]

Vince,

How tightly does the spring grip the shaft? I don't mean when it's supposed to be holding back the spring tension, I mean when you're cranking, and the "clutch" action is released. It's got to be a fairly snug fit, or it won't engage with the shaft firmly enough to wrap itself tightly around the winding shaft when reversed. You should almost have to unwind the spring a bit to get it over the shaft. As far as what you've made, it looks great and "correct".

That's exactly what the problem was. I remade the spring using a shaft with a slightly smaller diameter which made it fit much more tight on the proper shaft.
Thank you!

I have a fair supply of new-old-stock springs like this. If you could supply shaft dimensions, spring length, etc., I may have one for you.

The one I made seems to be holding for now but I'll get my measuring equipment out this weekend and see if I can get you that info.
much appreciated!

[Mr Grumpy]

It is a "non return spring" that as you mention, prevents the winder from unwinding. As to which way it should go, without a picture of one similar it could be trial & error. chances are 50-50. I could send you a photo from a Thorens motor, but due to travel, it could be only in about 2 weeks

I'm not sure a home made one would work unless you are a spring making professional!

Thank you very much for the offer, I think we figured it out.
I made a few springs out of soft wire wrapped around a shaft, then hardened them by heating and quenching in oil. Trial and error until
I figured out a good temperature before the quench and then tempered the spring. So far it's held up to a few complete windings but I'm not
sure I trust it. I'll likely take Jerry up on his offer of a new one if he has it.

[Mr Grumpy]

I think I got lucky, but I did manage to make a new non return spring for a Garrard motor. Certainly is possible to do at home: https://youtu.be/6yn4ah9bkNg

Brilliant video, wish I had seen it before! and I also wish I had a lathe and knew how to use it!

[mrrgstuff]

I think I got lucky, but I did manage to make a new non return spring for a Garrard motor. Certainly is possible to do at home: https://youtu.be/6yn4ah9bkNg

Brilliant video, wish I had seen it before! and I also wish I had a lathe and knew how to use it!

Thanks . The lathe is handy although not strictly necessary for making a spring. Where it was most useful in this process was allowing me to make a slightly smaller diameter shaft for winding on

[JerryVan]

Vince,

How tightly does the spring grip the shaft? I don't mean when it's supposed to be holding back the spring tension, I mean when you're cranking, and the "clutch" action is released. It's got to be a fairly snug fit, or it won't engage with the shaft firmly enough to wrap itself tightly around the winding shaft when reversed. You should almost have to unwind the spring a bit to get it over the shaft. As far as what you've made, it looks great and "correct".

That's exactly what the problem was. I remade the spring using a shaft with a slightly smaller diameter which made it fit much more tight on the proper shaft.
Thank you!

I have a fair supply of new-old-stock springs like this. If you could supply shaft dimensions, spring length, etc., I may have one for you.

The one I made seems to be holding for now but I'll get my measuring equipment out this weekend and see if I can get you that info.
much appreciated!

Happy to read of your success! When you get those dimensions, also include one for the distance from the centerline of the winding shaft to the centerline of the anchor screw hole.

[Mr Grumpy]

Happy to read of your success! When you get those dimensions, also include one for the distance from the centerline of the winding shaft to the centerline of the anchor screw hole.

Hey Jerry, I finally found my vernier!!!!

Diameter of Rod is 6.97mm ( so let's say 7?)
Distance from centerline of winding shaft to center of anchor screw is 21mm
Length of spring is 14mm, but this is a measurement of the one I made, not sure about the original. This length, give or take seems to work.