Machine back from a service but....
 

the thread tension spring still doesn't work, he said it wasn't necessary, but I'd really like it to do it's job.
I've had the tensioner apart, I see a cog inside and all it does is go round and round, should it be static does anyone know please?

We would like to help but we need some clarification. What machine are you dealing with? Make, model approx. age? Do you have any pics?

A cog as in gears? or are you meaning a finger that might slip into a hole? Thanks.

Hello Leonf,

It’s a 1955 Singer 99k.
inside the tension assembly there is a cog which the thread spring slips in to, there is no resistance so the spring doesn’t work. I’ll try to get a pic but it may be tomorrow when the light is better.

Thank you.

Hello again LeonF,

I found a picture online of the part I'm talking about, this is from the other perspective, i.e. the part that goes inside the machine.

http://mysewingmachineobsession.blog...-assembly.html
The cog on what they call the tension stud.

oK, I know the model. is it the spring that the thread goes through before it goes up to the lift arm, or is it the one that is bee hive shaped.? I can't access your link from here. Will look tonight.

Is it the one you can just barely see in this pic of a dirty face? https://www.quiltingboard.com/member...738-570444.jpg

Neither spring should just go round and round.

I would replace the broken part. I'm not sure which part you mean, I got cofused in the descriptions. There are two springs in the tensioner, both go on the tension stud; the inner made of a fine wire is the check spring for the thread, the outer is cone shaped and made of thicker wire. The check spring is a must for even stitching, I'm not sure how much play is allowed on the outer, but it's there to give the tension disks just the right pressure.

I forgot to add; I replaced the check spring on mine, it was bent out of shape it happens now and then if it's handled roughly. The other parts are much more solid, if anything is wrong it's usually just the order they put back together.