I made these plywood boxes that are designed to go above my kitchen cabinet. Problem is I did not realize that one section of the cabinet is slightly taller and I did not design this with enough tolerance.

I need to bring the top of these boxes down by about a centimeter. It is 8mm plywood and the end grain is just black because these parts were laser cut.

On hand I have:

• Chizzels
• Hand planars
• Palm Sander
• Drill

I am thinking about maybe puchasing

• 18v starlock multi tool (seems to be able to cut things somehow)
• Reciprocating saw
• Dremel with some sort of blade attachment

Currently I have gone at it with 60 grit sandpaper in the palm sander. And while that will eventually do it it is incredibly time consuming.

Dont care so much about precision here as I can sand anything to look nice. I am also open to maybe getting a new power tool if it would help at all here.

If bringing these into a proper woodshop would have a good solution I am down for that too. I am just not sure there is a safe way to say use a bandsaw or table saw on this and the vibration it does may just be too much.

Drilling it is difficult as the walls of the box can vibrate too.

https://preview.redd.it/nuj6p10pzwed1.jpg?width=4284&format=pjpg&auto=webp&s=0920bcbe1e1aa6b27bb87e87c997a3369cd76b1e