Anyone know what size/type of screws are used for the props on the IRIS? I lost one and am grounded until I can replace it.
3x8mm stainless button head
Any recommendations on where I can get some replacement bolts/nuts?
Are you asking about the nut that holds the prop onto the motor, the the screws that hold the motor to the arm?
The prop securing nut is an M5 metric nut. While a SAE #10-32 is close and can probably be crammed on, it will damage the threads and isn't recommended. Most hardware stores have at least some metric selection, and it is worth getting the right part.
The prop nut is M5
Star washer is 5mm ID 10mm OD
Motor mount M3 x 8, use break-able threadlocker