Large winged Wing nuts

[john]

WDS Ltd. also sell handwheels and knobs etc.
Machine tool parts places are good for this kind of thing.
Window sliders, Ian?

[shakey5]

I always used to use Elesa (http://www.elesa.com/catalogo_en_2_1_5_2.aspx ) or Rencol (http://www.rencol.com/products/plast...ssembly-knobs/) when I was designing materials handling machines. You may be able to get a couple of free samples to try!

[The Slug]

Thanks John, Shakey