by Mad Mick » 18 May 2004 15:38
When you say inverted Harry, do you mean that the flat part of the key is up, or down? I'm from the UK where pretty much every lock that I saw was installed so that the flat is at the bottom, the same as here in Bermuda and I imagine to be the same in the US. Apparently some locks in Europe are fitted 'upside down' when compared to the above.
Picking a lock which is in a different postition to what you are used to picking is always a bit more difficult. As is picking an installed lock when you're used to picking whilst sat on your couch. Try making a lock mounting board and picking the lock in the normal position, then invert it and try picking again.
As Safekey points out, tension is another factor and the suggestion of using a vise is a quick swap instead of using a lockboard. A lockboard, however, will give you a better feel for picking an installed lock, especially if you can clamp on another piece of wood to act as a door frame......

If it ain't broke.....pull it down and see how it works anyway!