I tested out a few machines. The 27 and the 15-30 were the best

The opportunity may present itself. I was already running late one morning and my shoe strap broke completely off.
My trusty Scholastic 6704 sewed it right back on with no hesitation.

Most of the domestic machines I see on eBay can sew leather, canvas, boat covers, sunbrella, upholstery...

They do sew it but not as nice as a big old industrial walking foot.

hahahaha with the sunbrella. That amuses me every time. That's EXACTLY what I want to sew with a domestic machine.

try it and you'll be surprised. The leather that I tried it on is the heavy kind and not the garment type leather. And I even used just the regular singer needle and not the needle for leather.

It works better if you do use the leather needle and yes they will sew heavy leather but for how long? Some times the foot will raise and then I worry what is going on if it doesn't have enough pressure to hold things down. The older heavy machines work best and to be sure it is a good idea to use a machine set up with a dedicated walking foot. If you are sewing for a task use a machine that is designed for a task.

I'm not surprised about the Singer 127. What needle did you use?

Any needle will work until it goes dull or breaks - best results for sewing leather is to use the leather needle.

The older the better for durability