I had a request to try sewing leather with the Ikea SY Sewing Machine.
I first have to say the machine it's self had no trouble with the thickness of the leather I used. I didn't have a leather needle so I used a size 90. The leather was a soft leather I use for backing beading projects.
I used the longest straight stitch and had to pull the leather along as I sewed or the feed dogs would have bogged down. I also found that I needed to use a 4/8 or better seam allowance. The smaller seam allowance allowed the leather to slip around and away from it's self.
I would not make leather my first project with this machine as the material is a challenge to sew. You can't use pins and such so you have to be able to guide the material and mind the seam allowance.
So to answer the question can you sew leather with the machine?
Yes you can.
The engine had no troubles with it.
The only trouble I had was that the feed dogs would eat the material if I did not firmly pull the fabric along.