Grindstone and Repair

How it works

Disenchanting	An enchanted item alone in a Grindstone loses all enchantments except curses (Curse of Binding and Curse of Vanishing). An Enchanted Book with no curses left becomes a Book.
Experience returned	Add up the value in the table for every enchantment on both input items, except curses. Half of that, rounded up, is the least experience dropped; the most is twice that minus 1 point.
Prior work penalty after	0 if no curses remain, 1 with one curse, 3 with two curses.
Combining two items	Two of the same item, one in each slot. The result keeps the durability left on both plus 5% of the full durability (rounded down), up to full. Enchantments of both are merged, then all except curses are removed. Costs no levels.
Stacks	The Grindstone gives no result if either slot holds more than one item.
Crafting grid repair	Two of the same damageable item, one each, anywhere in a crafting grid. The result keeps the durability left on both plus 5% of the full durability (rounded down), up to full. Only curses are kept, at the higher level of the two.
Mending	Each experience point from a picked-up experience orb repairs 2 durability instead of filling the experience bar.
Which item Mending repairs	One damaged item with Mending, held in either hand or worn, picked at random for each orb. Experience left after that item is fully repaired goes to another damaged Mending item, then to the experience bar.
Unbreaking	Each point of durability an item would lose is ignored with the chance in the table. Helmets, chestplates, leggings and boots use the armor chance; every other item, including Elytra and Shield, uses the tool chance.

Grindstone experience value of each enchantment level


Aqua Affinity	1	-	-	-	-
Bane of Arthropods	5	13	21	29	37
Blast Protection	5	13	21	29	-
Breach	15	24	33	42	-

Channeling	25	-	-	-	-
Density	5	13	21	29	37
Depth Strider	10	20	30	-	-
Efficiency	1	11	21	31	41

Feather Falling	5	11	17	23	-
Fire Aspect	10	30	-	-	-
Fire Protection	10	18	26	34	-
Flame	20	-	-	-	-

Fortune	15	24	33	-	-
Frost Walker	10	20	-	-	-
Impaling	1	9	17	25	33
Infinity	20	-	-	-	-

Knockback	5	25	-	-	-
Looting	15	24	33	-	-
Loyalty	12	19	26	-	-
Luck of the Sea	15	24	33	-	-

Lunge	5	13	21	-	-
Lure	15	24	33	-	-
Mending	25	-	-	-	-
Multishot	20	-	-	-	-

Piercing	1	11	21	31	-
Power	1	11	21	31	41
Projectile Protection	3	9	15	21	-
Protection	1	12	23	34	-

Punch	12	32	-	-	-
Quick Charge	12	32	52	-	-
Respiration	10	20	30	-	-
Riptide	17	24	31	-	-

Sharpness	1	12	23	34	45
Silk Touch	15	-	-	-	-
Smite	5	13	21	29	37
Soul Speed	10	20	30	-	-

Sweeping Edge	5	14	23	-	-
Swift Sneak	25	50	75	-	-
Thorns	10	30	50	-	-
Unbreaking	5	13	21	-	-

Wind Burst	15	24	33	-	-