Replacing Key Lock

[DDJC]

Hi all. From wandering round the NEC, I think that most motorhome builders fit a key lock system to a mid electric bed.

Problem is that the keys are standard flat and just break off inside the lock, requiring hours of fishing fun trying to tease out the broken key. I don't have the option of replacing it with a simple switch as two inquisitive boys go round pushing every button on the bus.

Anyway, I have decided to replace the key switch with one that uses the tubular keys, see pic. Cost less than a tenner for 90 deg 2 pole switch.

The switch is the same dimensions as the flat key thing I am replacing with. Naturally the existing hole allows very little clearance! The nut is 22mm and the barrel is 19mm. Has anyone got an idea of the tool I need to tighten the nut, without widening the existing hole?

Many thanks,

 

[autorouter]

Is a 22mm box spanner too big? Is the nut a hexagon, or one of those slotted round ones?

 

[DDJC]

Is a 22mm box spanner too big? Is the nut a hexagon, or one of those slotted round ones?

Ah, so its called a box spanner! Thanks. I've seen 'hollow nut wrench', 'overnut wrench', 'tube spanner', but t'internet had not really heard of them! Cheers autorouter, I'll get one. Its hex, by the way.