M2.3 x 6 Hardened Screw For Hyperlite Motor Bells (5 Pcs.)

These are the same ones that are used to hold the bell on the Hyperlite motors 
2207-2307-2405 Titanium shaft series

The original screw tends to strip easy because of the Loctite used by the factory.
The trick not to strip the head is to hold your soldering iron's hot tip on the head of the screws for about a minute before unscrewing it out.