technic/technic_chests/iron_chest.lua

local cast_iron_ingot
if minetest.get_modpath("technic_worldgen") then
	cast_iron_ingot = "technic:cast_iron_ingot"
else
	cast_iron_ingot = "default:steel_ingot"
end

minetest.register_craft({
	output = 'technic:iron_chest 1',
	recipe = {
		{cast_iron_ingot,cast_iron_ingot,cast_iron_ingot},
		{cast_iron_ingot,'default:chest',cast_iron_ingot},
		{cast_iron_ingot,cast_iron_ingot,cast_iron_ingot},
	}
})

minetest.register_craft({
	output = 'technic:iron_locked_chest 1',
	recipe = {
		{cast_iron_ingot,cast_iron_ingot,cast_iron_ingot},
		{cast_iron_ingot,'default:chest_locked',cast_iron_ingot},
		{cast_iron_ingot,cast_iron_ingot,cast_iron_ingot},
	}
})

minetest.register_craft({
	output = 'technic:iron_locked_chest 1',
	recipe = {
		{'basic_materials:padlock'},
		{'technic:iron_chest'},
	}
})

technic.chests:register("Iron", {
	width = 9,
	height = 5,
	sort = true,
	autosort = false,
	infotext = false,
	color = false,
	locked = false,
    protected = false,
})

technic.chests:register("Iron", {
	width = 9,
	height = 5,
	sort = true,
	autosort = false,
	infotext = false,
	color = false,
	locked = true,
    protected = false,
})

if minetest.get_modpath("protector") then
    minetest.register_craft({
        output = 'technic:iron_protected_chest 1',
        recipe = {
            {cast_iron_ingot,cast_iron_ingot,cast_iron_ingot},
            {cast_iron_ingot,'protector:chest',cast_iron_ingot},
            {cast_iron_ingot,cast_iron_ingot,cast_iron_ingot},
        }
    })

    minetest.register_craft({
        output = 'technic:iron_protected_chest 1',
        recipe = {
            {'default:copper_ingot'},
            {'technic:iron_chest'},
        }
    })

    technic.chests:register("Iron", {
        width = 9,
        height = 5,
        sort = true,
        autosort = false,
        infotext = false,
        color = false,
        locked = false,
        protected = true,
    })
end