I thought i had added more detail in an edit.
Inspiration was mainly from Del Pucket on youtube for “just do it ethos”. But i put a bit more effort in refining.
The neck is through the end of the box and sits in a notch at the back, i did that rather than go all the way through so they sit flat on the floor.
Hopefully you can see how i constructed the boxes thick oak ends rebated all round for the ply mean the box os pretty robust. Of it was for me i would have used a nice cigar box or possibly made a more refined box, but wanted kid proof.
Scaled length of the bigger one was 560mm and i just marked the other two fretboards starting at the first fret position. So about 530mm ish?
Frets were from chickenbone John, he seemed to have the best price for them. Tuners were amazon specials.
Boxes were 200mm by 250mm ish. In retrospect i would probably drop two or three frets off the high end and moved the bridge back a bit so they were a little shorter overall. But keeping the biggish fret spacing (lots of scope for **** fingers when barring the chorsd)
They are DAD tuned.