When grinding Gravel you always gets flint even if you want Sand.

maybe move Flint recepie to Extractor.

Also missing way to do String from wool

Running Version: TechReborn-1.16-3.4.2+build.48
but still exist at latest beta what i can see (TechReborn-1.16-3.4.3+build.72)

What to do to do my suggested fix:
under:
Add: TechReborn/src/main/resources/data/techreborn/recipes/extractor\flint.json
with: (type of exuipment only changed)
{ "type": "techreborn:extractor", "power": 2, "time": 200, "ingredients" : [ { "item": "minecraft:gravel" } ], "results" : [ { "item": "minecraft:flint" } ] }
Remove: TechReborn/src/main/resources/data/techreborn/recipes/flint.json
Add: TechReborn/src/main/resources/data/techreborn/recipes/string_from_wool.json
With: ( give same amount as if you craft wool)
{ "type": "techreborn:grinder", "power": 3, "time": 300, "ingredients": [ { "item": "minecraft:wool" } ], "results": [ { "item": "minecraft:string", "count": 4 } ] }