I designed this because I couldn't print one of those one-piece frames that hold the 608 bearing on my TinyBoy. uses: The big hole fits the 608 skateboard bearing's 22mm diameter The small hole fits the 8mm round wooden dowel from Lowe's or HomeDepot cut the dowel length to your desired spool size, insert into the small hole, insert the 608 bearing, then insert 2 more dowels into these bearings. its a tight press fit, so you can slide the dowel rod in or out to fit the size you need. Show me your makes so i can see how others will use this. Thanks!