I built one and ordered a 20mm-40mm screw kit. You'll definitely need a couple 40mm but forgot which other ones I used. This is the kit I ordered but you'll need to buy the nuts separately https://smile.amazon.com/dp/B0728FBS77/ref=cm_sw_r_cp_apan_i_ETX740YJC2NFWYE47T9G?_encoding=UTF8&psc=1