Removing old iron railing stubs

[Daddy Boots]

I'm want to instal new iron railings to the front wall built around 1885 and need to remove the old iron stubs from the coping stones. The stones are 20" x 30 " x 4". The old railings were cut off level and are 3/4" round set in lead in a 1" hole. The hole does not go all the way through the stone so I can't just knock them out ( gently). I've tried picking out the lead ( laborious), heating with a blowtorch ( the lead doesn't soften much and the stone spits) to no effect. There's around 40 to do. My latest idea is to drill a pilot hole and insert a screw so I can use a puller....I may have to use a blowtorch/acetylene to soften the lead but I'm very wary of cracking the stones...they are irreplaceable. Alternatively, drill pilot holes and use progressively bigger bits until the iron is drilled out....the lead should then come out easily enough. Any experience/advice ?What sort of bits would I need if I drill ?

 

[JohnD]

How would you feel about using a core drill?

 

[Daddy Boots]

Never thought of that ...looks the business...Do I aim to cut the lead or cut the stone ?

 

[JohnD]

cut the stone, I was thinking. Core drills for stone are common.

Take out a core that will remove the iron stumps and be big enough for you to put the new railings into (unless you are going to fill them with tinted mortar)

 

[Hitachimad]

Know anyone with a welder?
The easiest way i have found is to tack a bar to the stub, this gives you something to pull on, and its easy to heat the metal with a propane torch and the lead should soften without damaging the stones.