I would add from experience that when you cut a new leather belt to fit the treadle, use a craft knife/stanley knife to get a clean, straight cut. And squashing each end of the belt slightly flat with a hammer - place the end on a hard flat surface first of course - helps with positioning the hole accurately in the centre.
Also if you have a dremel tool with a tiny drill bit then use that to make the hole 1/4" from the each end of the belt. You could use a drill but a dremel is better as you have more control at slower speed.
I mention this as when I have tried to use a sharp awl or a small tack and hammer to make the hole - which is what most tutorials advise - I have usually had the end of the belt shear off and break. But that could just be a sign of my incompetence rather than anything...
When you get a new leather belt and have cut it to size, keep the bit you chop off and use it for some practice piercing first.
Also I thread dental floss on a needle and loop that a couple of times through the holes you have made before knotting the ends of the floss securely in order to join the ends of the leather belt together. I understand some people choose dental floss over the metal staple supplied with the belt in order to have silent treadling, rather than hearing the clicking of the metal joining staple on its way round the wheels.
I have a Bernina 717 sat in my treadle base; I have modded the balance wheel with epoxy putty so that it can be treadled and I didn't want to potentially damage the hardened epoxy with a metal staple, hence the dental floss.
My treadle mechanism is clean and rust-free so I don't have to engage in much dustworthy work, but there is some play in the footplate and the wheel bearings, so that is why I want to strip it down and pack the bearings with grease.
Also I just like taking mechanical things apart to see how they work