Crafting pipe cannot extract the objects in the furnace.
But the pipe can be put into the item.

is it the vanilla furnace? if it is, use a satellite pipe with the crafting pipe attached to a hopper bellow the furnace

@NarigudoBR
Hmm,I found a way.
satellite pipe(e.g. Iron ingots x8)
vanilla furnace
crafting pipe(e.g. coal x1)
This structure do not use a hopper.

Honestly, I do not understand what you mean. Can you attach screenshots of your original build?

Honestly, I do not understand what you mean. Can you attach screenshots of your original build?

Crafting pipes cannot pull items from above.

(1.7.10)

(1.12.2)
1.12.2 can not be automated using the method of 1.7.10, at least the furnace can not.
---------------By Google Translate
I am a Chinese player, so please forgive me in English.

Yeah, that's probably because the vanilla furnace is now sided, as in the slot in the inventory that gets accessed varies per side. Top is input, bottom is output, the rest is fuel, iirc.

Yeah, almost correct. Bottom is fuel and output, sides are fuel only and top is input only. So as it was said before by @baka-gourd: crafting pipe below with feeding fuel normally and the input via a satellite pipe on the top works fine.
This can be closed.