Machine needles
 

I have been using the walking foot for some quilting and the needle keeps getting loose and falling out while I am working. It was working perfectly , needle is flat in back. Could the tension from the walking foot causing it? If so, how do you fix it?:(

I have had that problem. I think it is because I no longer tighten the needle in place as much as I did previously. I also have the same problem with the walking foot itself. Of course, I sew a lot, and with some speed , which causes vibration, probably another cause. I just check both screws periodically, much cheaper than the timing problems these events can cause.

I keep a screwdriver next to my machine because I just don't have the strength in my hands that I used to have. This way I can tighten the needle screw and loosen it when needed with my handy screwdriver.

I bet it is just having it tightened enough.

I try to remember to check the needle tightning screw and tighten it numerous times during the day. Takes only a few seconds and saves a BIG headache.

Look and see that the fork that goes over the needle clamp is around the shaft, not the wide part. I had a buttonholer that did this; as the fork went up and down with the needle bar, it unscrewed the needle clamp.

I keep a penny by my machine to use as a screwdriver. It never goes missing.LOL.

a penny or a screwdriver....I just don't have the hand strength I used to....

I, too, notice that the vibrations loosen the screw. Just retighten.
Another problem I had was that inside where the needle lies, something wore out and had to be replaced. I couldn't use any needle smaller than a 16 or it would slip out. Not a costly repair, but it meant a trip to the dealer.