Is it smart to lube ignition tumblers
 

I notice that having a problem with the ignition tumbler is a real problem. Considering that the key and the tumblers are steel might it be wise to put a little Mobile 1 on the key and work it around, or, is that asking for trouble?

Use graphite to lubricate the tumblers. Oil can goop up over time when/if dust is introduced.

IMHO WD40 works best. Graphite powder will build up over time whereas excess WD40 can simply run out of the lock, and it does not get gooey over time.

-Jason

the best thing to use is nothing.

GRAPHITE
 

is the generally accepted lock lube - use sparingly and really only if you notice a problem with sticking (which you did in OP).

John in San Antonio

No Graphite,No WD40
 

Mercedes Part number 001 989 26 51 10 "Lock Cylinder Grease"

As others have said, dry graphite is what is generally recommended as lock lube. I use it by blowing it into the lock with a small tube-applicator, run the key in and out and turn it a few times, then take compressed air and blow into the lock to blow out any excess graphite. That seems to work well for me. Just remember to wipe the key off before you put it in your pocket or you will have black stains from it on your hand, pants and anything else you touch!

I too use graphite. There is a risk of packing the tumbler with it and instantly jaming up the works, which is probably where all the horror stories come from. Apply sparingly and repeatedly until you get just enough in to lube the tumbler. Graphite doesn't attract dust and evaporate off the volatiles like oils do, both of which will create a sticky, gooey mess inside the tumbler.

With graphite, the tumbler gets stiff again because it dissipates over time. With oils, it happens because the goo builds up over time and needs thinning again. Graphite won't help with locks that freeze up in winter, but oils will. Pick your poison.

Okay, here goes.
A former (he has passed away) locksmith suggested using WD40 every now and again, never graphite.