This is a fine example of how being lazy, or just trying to do a job quickly, is a Bad Idea (tm). I recently bought some old Fresnel lanterns (Strand Patt.123), most of which came without the bolts for fixing to the C clamp. Originally these were 3/8 whitworth thread, and wingnuts and bolts of that size are quite hard to find these days. The majority of my kit uses M10 nuts & bolts, which is just a tad bigger than 3/8 ww. So, I decided to enlarge some of the holes on the Patt 123s to 10mm. I got out the electric drill and a 10mm HSS bit. Then I made my big mistake. What I should have done was strip the lantern down to remove the yoke, and put it into a suitable vice before attempting to start drilling. But I was too lazy and in too much of a hurry to do this. I thought I knew better. The Patt 123s weigh about 2.5kg (5 lbs) and I thought that it would be fine to put the lantern on the ground, lens down, and grasp it firmly between my feet while drilling out the hole. Anyone familiar with Wallace & Gromit (especially "A Grand Day Out") will probably have guessed what happened next. The drilling started fine, and the bit cut through the first 90% without any trouble. Then it jammed. Solid. So what happened - I've got a 240v electric drill attempting to spin at high revs with quite a lot of torque, and a (relatively) lightweight object stuck fast to the end of the bit. To compound the problem, the drill is a few years old and has a button on the side which locks the trigger in the ON position (sensibly newer drills do not seem to have this "feature"). For a quarter of a second nothing moved as the torque built up in the drill. My feet's grip on the lantern gave way almost immediately and the Fresnel started to rotate rather quickly. On its own this would have been quite bad, but as you might guess, attached to the lantern was a 2' (60cm) tail with a 15A plug on the end. UK 15A plugs used for stage lighting are made from heavy duty rubber, and the three pins are pretty solid - especially when they start thrashing against your legs at the end of a fast moving cord. Ow! As my feet let go the instrument bashed against the side and top of my foot with a certain violence. The jolt as the bit seized in the hole caused me to inadvertantly click the lock button. Fortunately I was able to unlock the ON button and the rotation stopped almost immediately. To my amazement the lens was still in one piece, despite the fact that the lantern had bashed the ground a few times while whizzing around at high speed. I was even more amazed when I plugged it in and the lamp lit up (these tungsten bulbs are sometimes a lot more robust than we think). What didn't surprise me was the sharp pain in my leg where the plug had hit me several times, and another dull pain in my foot where it had been battered by the body of the lantern. I also felt very, very stupid. I was exceptionally lucky that I was wearing strong leather shoes and thick denim jeans, otherwise my injuries could have been far more serious. The moral of this story should be obvious. I have swallowed my pride and posted this in the hope that no one else gets tempted to be as hasty or lazy as I was.