why someone make bellows ribs but some folks make only 3 boards for bellows what is purpose of that 2 or more ribs.what will be without a that ribs i think i a bit know .WIll the cloth of bellows go into a chamber without a ribs

Hi Azur,
When I have made bellows they have been thus - for double action bellows I have a fixed center board, a moveable top board and a moveable bottom board.
When either of the moveable boards close the air inside forces the leather outwards which not only looks messy but you are loosing air that could be going into the fire.
By fitting ribs between the boards you can control this.
Does this make sense?
Wayne

yes i was thinking that leather (Canvas)go into chamber that is it like when i try with inner tube ithink that is perfect example
the inner tube go inside and make sutuff harder to work

Depending on the size and location of your valves, the ribs could also make it less likely that the bellows cover will interfere with the functioning of your valves. The larger the bellows and the wider the bellows open, the more likely the bellows cover will interfere with the valves if the bellows does not have ribs.