Pfaff 5.2 needle screw won't tighten to hold a new needle in.

-There’s a lever for the presser foot pressure, turn it to “1”.
-On that piece the lever is on to the rear, there’s also a white plastic flat head screw, turn it and that will release that side cover. (You’ll kind of still need to pry it off, it seemed a bit like I was going to break the plastic, but it comes off).
-Once it’s off and the inside part of the needle bar is exposed, turn the handwheel until the needle bar is at its top dead center position, revealing a smaller flathead screw that will be just above the light.
-Either tighten or loosen that screw to move the needle bar to correct height, which leaves exactly 11.5mm between the tip of the over-edge needle B and the top edge of the needle plate. I put an arrow on the pic I posted of where the screw I’m talking about is.
Hopefully that helps someone and makes sense.

It adjusts the position of the needle plate front to back.

:)

It adjusts the needle plate position front to back.

Upper thread breaks
needle may be in backwards
Raise the needle bar to the highest point then loosen the clamp screw to remove the old needle, place the new needle in the clamp with the flat side to the back of the machine
Push the needle all the way up to the stop or as far as it will go, then tighten the needle clamp screw
upper tension may be to tight
the needle may be bent or damaged
thread may be hanging up in bobbin case--check area for loose threads or lint

try changing the needle
Correct needle insertion is mandatory for proper use of your sewing machine.
Raise the needle bar to the highest point, then loosen the needle clamp screw to remove the old needle.
Place the new needle in the needle clamp with the flat side of the needle facing the back, (round needle, the groove in the needle should face away from the shaft).
Push the needle all the way up as far as it will go. Then tighten the needle clamp screw.

try adjusting the top thread tension-to see if the tension is too tight
rethread the machine--top & bobbin just in case the thread is caught some where
check to make sure there aren't any burrs on the needle plate

The timing is set at the factory. If the threads are not hooking together, then perhaps try one of three things.

1. remove the thread, and run the machine at full speed for three minutes or more. This warms up the hardware, loosens gelled up oil, and get's all the parts in allignment.

2. (and 3.) Check the thread tentions. On the top thread, it will be a dial with numbers, over a spring and two plates that the thread runs through. On the bottom, it's a tiny screw on the side of the casing that the bobbin sits inside.

If the machine sews loose threads, then tighten these, a bit at at time, and if the machine jams up with a knot of thread at the needle, then loosen these. I believe that if the sewn threads are loose at the top, the bobbin tention neeeds tightening, and if the sewn threads on the bottom are loose, then the top tention dial needs tightening.

Cheers.

If the needle bar is no longer available, the current needle bar can be repaired by cutting new threads in it and changing the screw. Not simple but not rocket science either.Most mechanics can do this.
sewman7

The threads inside the screw hole are probably stripped. If so you will need to have them rethreaded and a different screw used or have the needle bar changed.For this you should see a technician.
sewman7

your needle bar has been pushed up and is out of adjustment. You need to take off the side cover, there should be a screw on the back of your machine holding it on. Remove this screw, and remove the cover.You may have to remove the light assembly to reach the screw on the needle bar. Once you can see the needle bar, rotate the handwheel until you can see the screw on the needle bar. Loosen this screw SLIGHTLY until you can turn the needle bar. Hold and rotate the needle bar back and forth as you push down slightly. This will lower the bar.Lower it about 1/4 inch. Adjust the needles by turning the bar so that they are straight across. Tighten the needle bar screw so that the bar doesn't move. Turn the handwheel to see if the threads will be picked up. If not, adjust until they are. Tighten the needle bar screw tightly,reinstall the side cover ,and tighten the screw. Change your needles.Rethead and sew.
sewman7

Here ya go! For 1 Step Automatic Buttonholes: 1. Place button into the buttonhole attachment. 2. Push slider to hold button securely in the slot. The button goes to the back! 3. Put button foot onto needle bar--just attach it securely. 4. Place needle thread and bobbin thread UNDER buttonhole attachment and let 4"-5" of thread trail behind it. 5. There's a lever called a Button Stop to the left of the needle bar. Give it a gentle tug and pull it down. Pull forward. Hear a click? Now the machine knows what length to STOP sewing! 6. Put foot on pedal and machine will sew barrack closest to you first. It will continue all around until it makes complete rotation of each side. 7. You must do these steps for each of your buttonholes! IMPORTANT: Make sure you set your dial for making buttonhole pattern because that "tells" machine to zig zag, and use appropriate size needle for the particular weight of your fabric. A new needle before you begin is recommended. Turn screw on needlebar to loosen screw. Hold it so it does not slip down into the feed dog area! New needle is inserted flat shank toward back of needlebar as far as it will go. Tighten screw. Did this help? Hope so!
Jimmy