Related Products 6″ lap backing plate with one threaded adapter $125.00 excl GST 16″ economy sintered continuous rim lapidary blade. 400 x 1.3mm $225.00 excl GST Electroplated diamond core drill, 15mm dia. 8mm shank. $22.00 excl GST Quantity Add to cart Product added to wishlist. Add to WishlistProduct added! Browse WishlistThe product is already in the wishlist! Browse Wishlist Share TweetPin It Product code: 450015 Category: Core drills. Tags: core drills, Diamond drills, glass, glass work, lapidary.