Necchi 537fa handwheel will not move the needle. But when I turn the loosening knob inside the handwheel, the needle moves.

SOURCE: Handwheel doesn't move needle

Sounds like the connection between the handwheel and the needle as disconnected (needle bar). It appears from the picture that this is a version of a mass-market product geared for kids/very light duty sewing.

If so, you may be able to reconnect this by removing the side-cover or top-cover of the machine (if removable). The problem is going to be re-timing the needle with the hook/bobbin assembly.

If you are unable to reconnect or get the timing correct, a good local machine dealer/repair tech should be able to take care of it for you. Unfortunately, the cost of having a technician fix may be way more than you want to pay or the machine is worth.

Best of luck with your repair,
Kim & Linnette

SOURCE: Handwheel on Sewing machine no longer moves needle.

Actually you should have a "set screw" in the hand wheel. The set screw is usally locked down tight to keep the hand wheel from spinning freely. I f you can run the machine slowly and hold the hand wheel in one place but the machine continues running, then you do need to replace the "set screw". If you replace it you will find that you can offset some of the machines vibration by where you lock the wheel down. Trial and error is the only way to achive this adjustment, kind of like balancing the tires on your car.

SOURCE: Bobbin Winding

How do I wet wind a 2 inchs long bobbin using varnish.

Thanks
Gholam

SOURCE: my needle does not go up and down.

You need to check the needle bar first of all to see if you can move it up and down by hand, if you can then the screw on the needle bar may have come loose, or the very worst situation could be a broken takeup lever

Testimonial: "Thanks for the feedback. I think it was the screw. I tried tightening it with an allen wrench and it started working again, though I did not feel any significant tightening motion occurring."

SOURCE: My old Singer needle stopped moving when we

You must tighten the inner wheel after you have threaded a bobbin or bobbins.