How to Adjust Thread Tension Kenmore Rotary Sewing Machine Model 117.59 

I'm not sure. Older model sewing machines have metal parts. Metal parts eventually became plastic in newer model machines because of the noise level. I'm not sure whether or not plastic parts are available for that model.

This machine has a very common problem that causes the motor to be very loud but it's an easy fix. There's a little rubber wheel on the end of the motor that rests against the hand wheel. The little rubber wheel is what runs the machine. The problem is that in time the rubber wheel gets a dent from being pressed into the hand wheel -and that little dent makes a very loud noise when you use the machine. Kind of like a car flat tire. It's very easy to replace. Just search the internet for a "Friction Pulley" for a White Rotary machine (because the Kenmore is a White Rotary machine). Order one and replace it and the loud motor will be quiet again. When you're done sewing, stick something against the motor so it isn't touching the hand wheel and it won't get another flat spot. The new pulley is less than $10. I'd say it's a 90% chance that's the problem.