How do I determine the depth of a forge for coke and coal? I work with these two coals because the availability here sometimes there is coke other coal

Mine is ~3 1/2- 4" deep, and I use coal.

Steve

How much would it be in centimeters? It's for a blast forge

My bottom blast coal forge works well with coal and coke. The fire pot is 10 cm (4in) deep.

 

Do you have the air tube at a depth of 10 cm?

18 hours ago, Caballo bueno said:

It's for a blast forge

side blast or bottom blast?

19 hours ago, Caballo bueno said:

sometimes there is coke other coal

What kind of coal? coking coal(blacksmith/metallurgical) or anthracite.  

To create a neutral/reducing heat, ~4" of coke under your work and 2" above will work, no matter what kind of forge you have. If you use coking coal, you should only have coke in your firepot, not uncoked coal.

 

It's blast forge and if sometimes I use coal and other times coke

18 hours ago, Caballo bueno said:

depth of 10 cm?

It is pretty close to the fire pot maybe 15 cm.

but I want it for a blast forge

This may be a language problem, not sure. What do you mean by blast forge? Got a picture? 

I'm thinking a blast furnace for melting metal is what he means.

Might be thinking about a side blast forge.

could be a bottom blast forge as well.  Lol, that about covers the options,,,