Heat treated and case hardened to HRC 57-62. Made of precision-grade tool steel hardened and ground on all 6 sides of block. Accuracy and squareness on all sides within. Cross drilling design allows for efficient use of lower weight with maximum strength. Dimensions- 2″ x 4″ x 6, 18.3 lbs. 2 Pair 2-4-6 Blocks 23 Holes Machinist Precision 246 Jig. 2 Matched Pair 2-4-6 Blocks 23 Holes. 0002 Machinist Precision 246 Jig 2 4 6. 1 Pair 2-4-6 Blocks 23 Holes Matched. 2-4-6 Blocks 23 Holes Matched Pair Machinist 246 Jig Ultra Precision. 2″ x 4″ x 6. If there is any fault or problem with the product, please don’t be shy to express it, we will solve it at the first time. Quick Change Tool Post.