Tm150 roof hatch removal

[agrotron]

Trying to take a beacon off the roof and need to get the access panel off. The usual nothing goes to plans and can’t get the screws out . What is best way to get these screws out on Tm150. Some one has been at them before me and rounded them off and the other won’t budge. Thinking of welding a nut on the top but will it melt the roof? Thoughts or tips welcome. Thanks

 

[quattro]

Trying to take a beacon off the roof and need to get the access panel off. The usual nothing goes to plans and can’t get the screws out . What is best way to get these screws out on Tm150. Some one has been at them before me and rounded them off and the other won’t budge. Thinking of welding a nut on the top but will it melt the roof? Thoughts or tips welcome. Thanks

Could try drilling with anti clockwise drill bit

 

[Triangle]

Slot with a sliting disc or one of themeny ectractors left hand drills welder most lightly to melt it

 

[Grouse]

Soak in penetrating oil for a few days and use an impact driver. From the pics it looks like the steel plates may have been bedded in sealant - if that’s got on the threads they will be extremely difficult to remove - cut the heads off then ?