I made this tool for cutting panels for my Voron and I really wanted a straight cut, and as you may know this is really difficult when you are cutting with a knife and to many times the knife has wander off from the straight edge and ruined the sheet. 

This little tool was amazing to use, basically clamp your sheet together with a straight edge as a guide, push the tool against the edge and press firmly down and follow the guide. Do multiple passes  , the more the better and if you did thing right you should end up with a straight cut, finish it off with some light sanding and your done, no expensive tools needed :). 

Assembly is quite easy, put some glue before mounting the blade and once the glue has cured attache the handle to the base and you are good to go.