old Singer and it will sew up to and including leather, but sewing down pleats it no good
No domestic sewing machine is good for sewing down pleats in which you have to match up a tartan. A sewing machine pulls the fabric under the needle with the feed dogs, those things under the presser foot. When you have two layers (or more) of fabric, the dogs are pulling on the bottom layer and the top layer doesn't have that same pull so it's moving slower than the bottom layer.

This action can be countered (somewhat) in two ways. One, a walking foot which is a presser foot that has built-in feed dogs that will move in conjunction with the machine's feed dogs to keep both the top and bottom layers of fabric moving together. Two, careful management of your fabric as you sew. This could mean careful and excessive pinning and/or basting. The counter measures are more or less successful depending on the fabric that you're sewing. With fabrics such as tartan, your solution Robert is best.

Grats Brasilikilt on the sewing machine. I don't know your sewing experience, but making a kilt by machine is far easier than a jacket. Whatever you decide, good luck!