The Upholstery Forum

I just bought a new Seiko machine after 20 years on and off (mostly off) using a Chinese knock off of a Sailrite LSZ1. I just started the apprentice course. My question is in your opinion, are these stitches straight and if not, what am I doing wrong. I am not concerned about is the line straight. I am concerned about the slight z pattern in the stitches.

That’s common on certain machines. I can’t remember where but there are types that have the z pattern and machines that are straight. I don’t think it can be changed either.

It's the type of needle in the machine. It's called a reverse twist point needle. If you want a straight stitch use a round point needle.

The Needle? Really? that is very intriguing. I just bought the machine. It is a straight stitch walking foot and the needle is the one that came in it. Could you expand on the needle a little?

Yeah the stitches look normal. It really just depends on the look that you prefer.
Here is a diagram that explained the different needle and how they effect the way the stitches sit.

If you are using the proper needle, those offset stitches can also be the result of the material not being firm enough in relation to the thread size and the machine tension setting. I run into this problem when I try running lighter weight leather in my harness stitcher that I use for making holsters. The stitches will be perfectly straight when sewing two pieces of 6-8 oz. leather together. If I try running a top-stitch on upholstery leather or vinyl with that same machine, I have to back the material with a piece of duck canvas to firm it up and get the stitches to lay straight, instead of off-set like you're seeing.

Very good point @53Skylark! Thanks for sharing

@53Skylark ,

That is something I am going to have to look for. Thank you