Hair trimmer extension

I have 2 years of son which transform into monster when i try to hair cut :) No luck with barber shops and also its horrible for me to use scissors while trying to keep him calm. Ive discovered that he doesnt irritiated too much with hair trimmer machine but even most larger trimmer attached cutting is quite short for him. So ive decided to model and print my custom larger trimmer part for acceptable hair lenght. Iam not sure that trimmer parts are standart all around world but it worked on diff