I've had a cheapo hammer drill for ages, bought it in Wilko or Payless
for around £15. It's fine, EXCEPT that the ruddy thing keeps slipping
into hammer mode. There is a sliding square-section button that you
push one way for impact drilling or the other way for non-impact
drilling. But this button constantly vibrates towards the "impact"
setting. I have to remember to press it in (non-impact) each time I
drill a hole. Sometimes I forget and I get the hammer action kicking
in on a 2mm drill bit!

Any ideas on how to "persuade" the button to stay in non-impact mode?
I've thought of jamming something in the square hole, but I thought
I'd ask here first.

Thanks.

MM