Stuck brass screws

I have three brass screws which I'm having problems with.

There is this half a furnace shaped like a barrel. There is a ceramic refractory bowl in the bottom retained on by a steel/iron ring screwed to the body.

One screw rotates freely but won't move ir or out so I'm guessing it is snapped. The other three are firmly stuck.

On the top half the refractory had cracked and fallen out anyway. All 4 screws I tried to remove ended like this

The brass is just so weak it falls apart.

Penetrative oil has been sprayed vigourously to no avail. Has anyone got other ideas that might loosen them?

Drill them out.

Drill and tap for next larger size screws.

Fit new screws.

Next! JD

DON'T try Easyouts! (A misnamed tool)

Left hand drills MIGHT work, if you have any the right size, otherwise, as JD says try drilling, but try a tapping size drill first, and then clean up the threads. If that fails, as said, drill out and tap next size up (Assumes that there is enough meat left behind the scenes for this)

Maybe applying an anti seize compound when fitting the new screws may help for next time, whenever that may be?

Howard

One screw rotates freely but won't move ir or out so I'm guessing it is snapped. The other three are firmly stuck.

You should not guess. It could be that the refractory, or insert in the refactory has allowed the screw to rotate although it (the screw) is completely intact. It may be that these screws are actually threaded into the metal.

As above, remove by drilling any take remedial action as necessary.

Drill them with a drill about half the diameter of the screw as good as you can in the middle. Then if you have an old 5 side clock reamer you break that so it just fits the hole you drilled and turn it anti clock wise until the broken of screw starts turning. It is the reason why you you do not throw away your old broken reamers. Niko.

Have you tried cycles of freezing/heating it? The different coefficients of expansion may help loosen the brass?

Are they left hand thread ?