Custom Crafter, Gravel to/from Stone Blocks

4 Gravel -> Cobblestone

  # -Z  Sound, Piston Compress
  execute @e[type=ArmorStand,name=GM4_CustomCrafter,score_GM4_crafting_min=1]
    ~ ~ ~ playsound tile.piston.in @a[r=4] ~ ~ ~ 1 1.3 1

  # +Y  Result
  execute @e[type=ArmorStand,name=GM4_CustomCrafter,score_GM4_crafting_min=1]
    ~ ~ ~ blockdata ~ ~ ~ {Items:[
      {Slot:8b,id:"minecraft:cobblestone",Damage:0s,Count:1b}
    ]}

  # -Y Recipe
  execute @e[type=ArmorStand,name=GM4_CustomCrafter] ~ ~ ~
    testforblock ~ ~ ~ minecraft:dropper -1 {Items:[
      {Slot:0b,id:"minecraft:gravel",Damage:0s,Count:1b},
      {Slot:1b,id:"minecraft:gravel",Damage:0s,Count:1b},
      {Slot:3b,id:"minecraft:gravel",Damage:0s,Count:1b},
      {Slot:4b,id:"minecraft:gravel",Damage:0s,Count:1b}
    ]}

Cobblestone (any Type) -> 4 Gravel

  # -Z  Sound, Stone Break
  execute @e[type=ArmorStand,name=GM4_CustomCrafter,score_GM4_crafting_min=1]
    ~ ~ ~ playsound dig.stone @a[r=4] ~ ~ ~ 1 1.3 1

  # +Y  Result
  execute @e[type=ArmorStand,name=GM4_CustomCrafter,score_GM4_crafting_min=1]
    ~ ~ ~ blockdata ~ ~ ~ {Items:[
      {Slot:8b,id:"minecraft:gravel",Damage:0s,Count:4b}
    ]}

  # -Y Recipe
  execute @e[type=ArmorStand,name=GM4_CustomCrafter] ~ ~ ~
    testforblock ~ ~ ~ minecraft:dropper -1 {Items:[
      {Slot:4b,id:"minecraft:cobblestone",Count:1b}
    ]}

Smooth Stone -> 4 Gravel   (could be made to handle all stone types)

  # -Z  Sound, Stone Break
  execute @e[type=ArmorStand,name=GM4_CustomCrafter,score_GM4_crafting_min=1]
    ~ ~ ~ playsound dig.stone @a[r=4] ~ ~ ~ 1 1.3 1

  # +Y  Result
  execute @e[type=ArmorStand,name=GM4_CustomCrafter,score_GM4_crafting_min=1]
    ~ ~ ~ blockdata ~ ~ ~ {Items:[
      {Slot:8b,id:"minecraft:gravel",Damage:0s,Count:4b}
    ]}

  # -Y Recipe
  execute @e[type=ArmorStand,name=GM4_CustomCrafter] ~ ~ ~
    testforblock ~ ~ ~ minecraft:dropper -1 {Items:[
      {Slot:4b,id:"minecraft:stone",Damage:0s,Count:1b}
    ]}

Stone Brick (Any type) -> 4 Gravel

  # -Z  Sound, Stone Break
  execute @e[type=ArmorStand,name=GM4_CustomCrafter,score_GM4_crafting_min=1]
    ~ ~ ~ playsound dig.stone @a[r=4] ~ ~ ~ 1 1.3 1

  # +Y  Result
  execute @e[type=ArmorStand,name=GM4_CustomCrafter,score_GM4_crafting_min=1]
    ~ ~ ~ blockdata ~ ~ ~ {Items:[
      {Slot:8b,id:"minecraft:gravel",Damage:0s,Count:4b}
    ]}

  # -Y Recipe
  execute @e[type=ArmorStand,name=GM4_CustomCrafter] ~ ~ ~
    testforblock ~ ~ ~ minecraft:dropper -1 {Items:[
      {Slot:4b,id:"minecraft:stonebrick",Count:1b}
    ]}

Mossy Cobblestone -> 4 Gravel

  # -Z  Sound, Stone Break
  execute @e[type=ArmorStand,name=GM4_CustomCrafter,score_GM4_crafting_min=1]
    ~ ~ ~ playsound dig.stone @a[r=4] ~ ~ ~ 1 1.3 1

  # +Y  Result
  execute @e[type=ArmorStand,name=GM4_CustomCrafter,score_GM4_crafting_min=1]
    ~ ~ ~ blockdata ~ ~ ~ {Items:[
      {Slot:8b,id:"minecraft:gravel",Damage:0s,Count:4b}
    ]}

  # -Y Recipe
  execute @e[type=ArmorStand,name=GM4_CustomCrafter] ~ ~ ~
    testforblock ~ ~ ~ minecraft:dropper -1 {Items:[
      {Slot:4b,id:"minecraft:mossy_cobblestone",Count:1b}
    ]}