Methods to remove lead

[country gent]

Actually you may not need to melt the lead. Picking it up just a few inches. You don't want that much weight falling very far. And an even heat coming up slow may expand the base enough to release the lead from the base letting it drop out in one chunk. Most cast iron was cast with draft in it to release from moulds and this works to your advantage as the hollow gets bigger as it goes out. A lot of the old casting were 2-3* draft angles allowing for a quick release.
Also if using heat bring it up slow and even cast iron doesn't like fast expansion rates or uneven expansion and will crack if not done slowly. At 900lbs estimated above a good lift and blocking should be used for safety reasons.
I would block it up on a solid floor and give it a couple taps around the top out side to see if plain vibration would move it any first. Then a small fire slowly increasing temps as it warms expands to an fire the encompasses the whole base. Remember to do this slowly.

[merlin101]

Couple good ideas here but I have a question, if that base is filled with lead it's there for a reason as a counter balance, what are you going to do with out that weight when you use the machine? Basically the machine is going to be very top heavy, like 700lbs or so!

[country gent]

A lot of older machines had weight added to reduce chatter also as they wore. Removing weight may cause a chatter problem

[JimB..]

My first thought was to drill through from top to bottom and then apply heat to get the lead to run out what is now the top. The lead should absorb a lot of heat, heating the iron slowly, but you might still crack the iron. I like heating it upside down because I’d prefer to do the extra work than to risk it falling out of the iron shell.

All that said, I wonder of you could cut a bunch of it out with a router connected to a shop vac or if the lead would just gum up on the router bit.

[triggerhappy243]

QUOTE: All that said, I wonder of you could cut a bunch of it out with a router connected to a shop vac or if the lead would just gum up on the router bit.

you would need to keep the cutter wet with something like wd-40 but the shards of lead would become projectiles.

[Lloyd Smale]

if its cast steel you probably are going to crack it if you use heat. At least if you heat it enough to melt it all out. Id try drilling a 3/4 in hole at every corner and take a saws all and run it all round the sides and then heat the top enough to get it to fall out.

[1Hawkeye]

Here's an outside the box thought. What if you cut through the steel frame with an angle grinder? Say one cut top to bottom on each side then you might free up the lead or have a point to pry off the steel frame.

[JimB..]

QUOTE: All that said, I wonder of you could cut a bunch of it out with a router connected to a shop vac or if the lead would just gum up on the router bit.

you would need to keep the cutter wet with something like wd-40 but the shards of lead would become projectiles.

Catching projectiles is easy enough, but routing wet would be no fun.

I’m back to drills, maybe a forstner bit at slow speed with wd40 would produce shavings.

[godzilla]

Wow, thanks for all the suggestions guys! The base is part of a forging machine, a anvil sets on top of it. I imagine the lead was poured to compensate for the lack of a foundation that the machine requires. Im trying to generate funds to complete a building that this machine will be going into, otherwise I would not fool with it.