My sewing machine needle is hitting the top of the needle plate

The manual should be able to help you

https://sewingdude.files.wordpress.com/2012/09/kenmore-158-1750-manual.pdf

Here's a manual you can order for your machine:

Kenmore 158 instruction manuals 3

This sewing machine vendor sells a needle plate for your Kenmore. Because the needle hole in the plate is wide, it most likely has zig-zag capability. A straight stitch machine would not need a wide needle hole if it sews only forward & backward.

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Sounds like your needle is set to off-center. Check your manual. You may have a straight-stitch plate in your machine but you have it set to stitch off center or it is set to zig-zag stitch and the needle is unable to clear the stitch plate.

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The needle should not hit the bobbin holder at all. Do you have the needle inserted all the way? If it is too low, it will hit. If you are saying the needle is hitting the sides of the needle plate where the needle goes through, then the needle is too wide for the plate. Either use a narrower twin needle or see is a needle plate with a wider needle hole came with your machine. Some decorative stitches can't be used with a twin needle because the combination of width of stitches and width of needle is too wide. In that case, narrow the stitch width until the needle doesn't hit the needle plate or use a narrower twin needle. I hope I have helped and answered some of your questions. Good luck.

try another needle and see if the needle still bends,, if the needle
still does bends then there could be something wrong with the needle
bar and the machine needs to be checked.

This machine, when you have it on straight stitch, will sew with the needle to the left. If it's hitting the pressure foot, you may have the wrong pressure foot on the machine. If it's hitting the needle plate when you have the pressure foot removed, it's possible you have set for zig zag and you have a straight stitch needle plate on the machine. I believe this machine came with 2 needle plates. One for straight stitch, and another for zig zag.

Most likely reason is the needle is bending. Try using a thicker needle. Heavyweight fabrics such as denim, duck and canvas. Use a 90/14 or a 100/16 needle if sewing on these fabrics; a lighter 70/10 or 80/12 if sewing on cotton. Singer codes this with a blue top.

J

Please post any question is comment and don't forget to rate my free answer.

the thread wrapped around the bobbin case and tangled around to mess up the tension try to readjust the tension

Hello,
Here are several things to try.

* When you insert your new needle, make sure it’s positioned correctly (usually with the flat side away from the bobbin, but consult your manual), that it goes all the way into the holder, and that the screw is securely tightened.


If there doesn’t seem to be a problem with your needle, try the following:

* Check your pressure foot and make sure it’s attached securely.


* Change your pressure foot Your pressure foot may be bent, causing your needle to hit it.


* Don’t sew over pins a needle that hits a pin can break. Always remove the pins from your fabric before they reach your needle.


* Don’t pull your fabric as you sew. You could be bending your needle back, causing it to hit your needle plate instead of going into the hole. Just guide your fabric, letting it feed on its own.


* Check your needle plate and make sure it's securely in position.


* Change your needle plate. If you’ve been using a straight stitch needle plate (a plate with a small hole, often used for sewing fine, delicate fabrics), switch to a needle plate with a wider hole.


* Check the position of your needle. Sewing machines with zigzag capability allow you to adjust the position of your needle – right, left, or center. If your needle is not positioned correctly, it may be hitting your needle plate or pressure foot.


* Un-thread your machine and remove your bobbin. Clean any loose thread or lint out of your
bobbin case. Re-thread your machine, reinsert and re-thread your bobbin.

* Change your bobbin. There could be a nick along the edge of your bobbin spool that’s catching your thread as you sew.

Also, before you start to sew a seam, hold the upper and bobbin thread tails. Hold them back
and out of the way as you sew your first couple of stitches. This will keep them from getting
caught in your machine.

I hope these solutions help you.

That sounds like it's definitely an internal adjustment. The machine will need to be opened up and the left/right adjustment taken care of. Is this machine one that you can open the top easily, or is it the type that has the front and rear shell?