£10 argos drills

Can someone please talk me through the grub screw method? I understand the threading , etc but I'm confused as to how deep the screws are going and if they are meant to touch the notches on the ring or the ring itself? I tried the o ring and it snapped one of the bolt holes on the motor mounting!

The grub screws sit in the notches.

As in between the raised points on the ring gear? So it basically stops the whole ring gear rotating yeah?

correct 2 per motor is best don't go to far otherwise you will lock up the gearbox

Would you say putting the screws either adjacent or opposite is best?

Another SBS... http://www.robowars.org/wikka/DrillHacking101

Would this method not leave an amount of play in the gearbox?

must admit i always have drilled and tapped a 5mm and used grub screw but this should work quite good (may try it next time)

I just take off the chuck but leave the clutch in place. Works fine.

Just grub screwed my motors. Seems to have worked a treat! Threw loads of grease in there as well for good measure!