FWIW, all a Glock front sight tool is, is a 3/16" nut driver. The cheapest Dime-Store one to be found is more than adequate. On some Glocks you may find it desirable to file or grind down the outside diameter to fit. Be aware that the very thin headed flat screw can be easily snapped off. It needs only minimal snugging down, no more than 1/8 turn after all the slack is taken up. As Frank mentioned degreasing is important as any oil can markedly reduce the holding strength of Loctite.