I have a regular LEGO baseplate that I'd like to shave down to fit into a car travel kit. Does anyone have experiencing cutting a baseplate? I'd love tips on tools or technique!
The easiest way to do this is to score the baseplate with a straightedge and knife. Once you've made a deep enough cut, you should be able to bend and break the plate where you've scored it. You may want to sand the edge to clean it up a bit.
There's a more detailed set of instructions in this Instructable.
Press down 8 x 2 / 10 x 2 / 16 x 2 plates etc. to the board to give you a cutting line, make sure they are firmly pressed down.
On a flat surface, gently score the board tight up to the edge of the plates 2 or three times then firmly bend to snap the board and finish by trimming a small 45 degree.
Cut at the new sharp corners and hand finish with fine rubbing down paper. I retail vintage / used Lego and we often cut down damaged boards to make smaller ones and this method works well so long as you don't try to cut too hard and lose the line up against the guiding plates.
I advise you to use a sandpaper. First use a clamp to fix the part you want to cut, then use sandpaper. Instead of trying to cut it i think you should grind it with sandpaper.