[size=14pt]Removing a dead latch lock when key not available, cont'd.
Tools - 750 watt corded drill, demolition chisel, and hammer.
Consumables - Sutton Cobalt 9 and 12mm drill bitts and WD40.
After reading the previous helpful replies to this thread, I discussed the locks removal with a locksmith when I purchased its replacement. He suggested that as I had access to both sides of the door, then using an angle grinder with thin cutting discs to cut the lock's bolt would be quicker than drilling the cylinder out. He said it may take 2-3 cutting discs as the bolt is hardened steel.
However this external door and its jams had been incorrectly installed back to front about twenty five years ago by a 'Professional' builder. Consequently I discovered that a 100mm cutting disc had insufficient reach to cut the lock bolt, even after I cut off the lever. [member=20326]SittingElf[/member] and others may not have this problem.
So, using 9mm and then 12mm Cobalt drill bitts and frequently lubricating with WD40, I drilled through the cylinder centre in approx. 10 mins. Then giving the remnant of the leaver a sharp hit with hammer and demolition chisel the door was open.
The rest of the day was spent sanding.
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