Hi Erniuss,
The problem, at least on my Tekkit, is that the output icon is not shown in the crafting grid when you enter a correct recipe -- but if you hover the output slot with your mouse you'll see it highlight, a quantity digit being shown and you can "pick up " the crafted item. Once in your inventory the icon is shown correctly.
For example, I can take a ruby saw and place it above a cobblestone block in the grid and then click on the (empty looking) output slot to grab two cobblestone slabs. I think the recipes are the same for both the "forge" and "immibis" microblocks so, saw to the left of the block to make pillars and nooks; saw above to make slabs, panels and thinner pillars. Arrange eight slabs/panels/covers in a ring to make same with hole in the middle.
All the best,