helicoil
I might be misunderstanding what screw you are talking about. But if its the little set screw(asc#3862) that holds the hinge pin in it is 5-40x1/8 which requires the $70 istalation tool.IF you are talking about the screw that holds the hub to castor block (asc#3875)then its a 4-40x11/32.You can get the 4/40 helicoil with part #93060a001 (hand install tool)from mcmastercarr Check it out . I used to have thread repair inserts that was installed with a flat head screwdriver , I wiil see if I can remember who made them .They worked great,still have them in my car.