Cones and Mandrels Cones and Mandrels Cones and Mandrels (119 ratings) £1.90 Cones and Mandrels: [Choose]Pink Stone Cone (fine)Ruby Stone Cone (coarse)Honing Cone (+£2.65) Quantity: at £1.90 each Add To Basket Ruby and Pink Stone Cone Mandrels These are used to sharpen loop knives and the hooks of knives. They are inserted into the end of the Spiral Tapers. The Ruby is coarse, followed by the Pink. Honing Cone This is a compressed cotton cone infused with the special Grey Compound. This is used after the Pink and Ruby Stone Cone Mandrels to hone the loops and hooks of your knives.