Drilling them is not a problem - well, yes it can be!
First time I did it I made a drill holder, on my lathe, and soldered the drills into it. Was a bit of a drag and slow but I got there. I pilot drilled, removed the bit from the holder, enlarged the hole in it and soldered in the next size drill bit. I have now picked up some some long drills for the job (surprisingly- they popped up in a model engineering sale when I didn't need them, but I bought them for a song with the long view in mind!), but back then it was cheaper (and easier?) just to do that one key - after all it was the only one I was ever likely to want to remove, wasn't it? - er, wrong!!
. Neither was it a CS; smaller key, less of a problem.
The secret is to go carefully, start with a small pilot hole so as to get it centred and aligned precicely and then enlarge, preferably in stages being very careful not to break off a high speed steel drill bit in the key - it is hard enough without making things worse! Having a torque limit on the electric drill helps to reduce the risk of breakage. Really sharp drill bits are a must. Taking your time is a must too! Tiring or rushing can so easily lead to broken tips.
Having done a few, I don't worry so much. Just experience, I suppose. That first one to a non-engineer can be daunting.
Regarding preparation for gib key removal; most will have a preferred release oil for pre-soaking for several days, or even weeks. Mine is a Danco product. Not sure whether the newer products are as good as the old ones (health and safety, 'banned' substances etc) so my near empty cans are used very sparingly these days. I find it magic compared to quite a few others I have tried. Scrupulous cleaning/derusting of the exit path for the key and the flywheel are most important. Preparation is a LOT more than half the job of pulling off a flywheel! The initial movement is the hardest part so cleaning right into the edge of the flywheel is the 'key'area for attention.
Remember, if you think you are going to make things worse, get help as it is cheaper than the alternatives. Carbide tipped drills can be used to recover the situation but the more it is butchered, the harder it is to recover the situation. But remember this; they were designed for easy service and robustness. They are difficult to damage as long as exteme force or totally inappropriate procedures are not inflicted on the parts. The 'oids' may be a little more fragile than the original Listers - after all, the originals are at least twenty years old and could be over seventy.
Hope this helps and doesn't terrify you too much.
Regards, RAB
