Needle will not stay in? i install needle, tighten thumb screw and the needle falls out??why??

The manual should have instructions. Most overlocker needles have a screw that holds each needle in place. Just loosen the screw with the screwdriver that came with your machine, slide the old needle out (note which direction the flat side of the needle is facing), insert the new needle as far up as it will go, and tighten the screw. Don't lose those screws or drop them inside the machine. If you remove a needle so you can serge without it, be sure to tighten that screw so it doesn't fall out.

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Be sure to unscrew the set-screw and extra turn and then insure you are pushing the needle all the way up before tightening it. Could also mean the set screw is stripped...

You need to tell us make and model when you post a question for us to give you a really good answer.

Here the generic way to replace a needle:

1. Raise the needle fully.
2. Look for a thumb-screw right where the needle joins the needle mechanism.
3. Loosen the thumb-screw and catch the broken needle when it falls out.
4. Put a new needle in the place occupied by the broken needle. Be sure the flat side of the needle is away from you.
5. Tighten the thumb-screw.

All the machines I have had have a twist screw, right beside the needle, on the right of the needle. Raise your needle lever into the upright position, so the needle isn't in the machine. You use your thumb and first finger and turn the twist screw backwards. You can then pull your needle down and it will fall out of the needle holder. Insert a new needle, making sure the holes in the needle are front to back, not side to side, and tighten the twist screw.

There is a thumb screw by the needle. Just unscrew it enough to be able to remove the needle by pulling straight down. You may need a small screw driver. HOWEVER, when you take the needle out, by pulling it down, notice where the FLAT SIDE IS It may face backwards or forwards, but it is important that the new needle is inserted this same way. Push the new needle up into the opening where the old needle came out, making sure it is pushed all the way up. You may need to unscrew the thumb screw a bit more to facilitate insertion. Jiggle the needle while pushing it up into the opening to be quite sure it is seated properly. Then, hold the needle with one hand and tighten the thumb screw with the other. Using a small screw driver, (one should have come with the machine), tighten the thumb screw all the way down. No need to over tighten, just make sure it is really snug. Piece of cake:) Good luck. She may have broken it, but he needs to read the manual:)

You either don't have them in the needle holes and or your not tightening the screws to hold them in

1 - Loosen the knurled thumb screw on the right side of the needle clamp.

2 - The old needle wil probably fall out, if not you can simply pull it straight down to remove it.

3 - Slide a new needle up into the needle clamp.

4 - Tighten the knurled thumb screw on the right side of the needle clamp with your right hand while holding the needle up with your right hand.

there is a little coller with a thumb screw that tightens and holds the needle ..that might be missing .. make sure you have the correct type needle ... the little thumb screw should tighten down the needle if its assembled correctly .. make sure its not backwards .. i have a few of those machines .. i will look closer (if i can find them) if you need more help

My husband used a 5/64 allen wrench to reattach my needle holder. There is a small black set screw directly above the screw that you tighten to hold the needle in place. I just looks like a small black hole, but there is a screw in there. Use the wrench to tighten it and you should be good to go.

There is a set screw above the needle pin screw which tightens with an allen wrench--try that.