HI All How do you reduce the cabinet depth from 12 inches to 8 inches? Cut back with a tablesaw but then how do you rebuild the back?

 

If it is a newer cabinet they are difficult to trim because everything is glued together.

Could run down a saw on the four sides and then put a sheet of finish plywood or luan on the back stained and finished to match.

 

Besides some plywood to stiffen the back you'll also need to replace the framework - typically 1x1s but 1x2s would also work. Study how the cabinet is assembled at the back and more/less recreate that.

 

The holes for the shelf support pins may need to be re-drilled if the back row gets cut out when the back is cut off.

The easiest way to attach the new back would be by using cleats to hold the back. The cleats would be inset by the thickness of the back so that the back would be flush with the ends, top, and bottom. The back corners of the shelves would have to be notched to fit around the cleats.

 

I'd be concerned that there is no support to hang the cabinet on the wall. Yes, you can install it, but what happens when you start loading weight into the cabinet. Its more that just a cut down and hang project.

 

I would just glue and staple 1/8" or 1/4" hardboard or Luan or plywood to the cut edge in back...

if it's between cabinets you won't see it. If it's a stand alone cabinet, just add a skin to each side. The face frame should project enough to accept one thin skin on each side, if you want to cover up the piece you add on back, you would add the side skins last.

Add an interior 1x4 cleat across the interior back (at top and bottom) so that you have a place to attach the cabinet to the wall with cabinet screws. The cabinet sides should fasten to the ends of these 1x4 cleats. (Before side skins go on)