I made a fabulous discovery a little while ago whilst looking for information on my spinning wheel, a little upright Wendy from New Zealand made in the early seventies by Philip Poore. It has a rather limited range of ratios 7:1, 8:1 and 9:1 which has frustrated me in the past trying to spin laceweight. The ratios mean that the flyer spins and adds twist into the fibre at rate of 7, 8 or 9 twists per treadle. Think of them as gears perhaps.
My discovery was VJ Handycrafts and Spinning Wheels in New Zealand. Amongst many other things, Joachim makes new whorls and bobbins for old Philip Poore wheels! They were out of stock when I first looked but I left an inquiry and I received notification as soon as more stock had been made. Joachim makes them in so many different sizes, it took me a while to settle on which ones.
And two extra bobbins. I have had only three bobbins till now and if I am spinning a three ply yarn, I have to hand wind my singles onto to toilet paper rolls (classy eh!) in order to have enough bobbins to fill with plied yarn. No more toilet paper roll winding for me.