Simple, cheap, realistic and amazing maths and engineering resources. Please ensure you supervise.
TUTORIAL Nuts and Washers: 4 Easy Beaded Beads Made with Peyote Stitch - gwenbeads on etsy
Everything you wanted to know about screws, nuts, bolts, etc. More
Heat Your Room with 1 Candle plus Flowerpots, Nuts and Washers | Permaculture Magazine
These are very cute and excellent for fine motor and bilateral coordination skills. l would paint the washers green - nail polish works great on metal washers.
Zip-it Tree Ties 15 ft. x 5 ft. Garden Trellis Kit With 50 ft. 16 Gauge Galv Looped Wire, Netting, 4-Eyebolts, Nuts and Washers SC16-2-50 at The Home Depot - Mobile