rounded rusted self tapper

[Alzey]

The bus failed the MOT on a couple of small things, one of which was the headlight was out of adjustment, anyway, I replaced the offside addjusters, tidied up the rust etc and thought I'd do the other side as well, except one of the four tiny self tappers has been mullered by someone in the past. What's the best way to get it shifted ? The impact driver hasn't worked because the area is little fragile and I'm reluctant to give it a proper clout, anyway I'll go put the kettle on while you sages start composing your replies, best suggestion can have a choc biccy.

[slippy8v]

if you can get a Dremmel you could cut a slot in the head for a flat head screwdriver

[weimarbus]

you could try a 'dremmel' type tool with a thin cutting disc and grind two flats on the head to provide a better grip for small 'mole' grips. slotting the head would probably weaken it too much, be aware that if the head shears off you would not be able to drill the screw out, 'cause self tappers are too hard. Good luck

[weimarbus]

if you can get a Dremmel you could cut a slot in the head for a flat head screwdriver

beat me to it

[Alzey]

In the end I filed the head off with a power file, (great tool) then took the headlamp surround out, then reached around with the pliers and wiggled the remaining 2mm of screw out. They are tiny !!!
Under these circumstances I'm unable to award the choccy biscuit and following consultations with the other judge (six year grandson) we have decided to award the biscuit to me.

The Dremmel suggestion was highly commended.

[weimarbus]

Glad your sorted, my wife would say I don't need more biscuits anyway

[Mr Bean]

I often get such screws/bolts out by gripping the head with a largish mole wrench straight on. The advantage here is that if you can get a grip however tenuous the mechanical advantage is many times greater than any screwdriver may apply plus in spite of your attempt to hold the wrench straight you still impart a slight wiggling which will further assist breaking the initial stiction. The jaws must be crisp and sharp and this can be facilitated by giving them a touch on the grinder if you have one.
Cheers
CS