How hard can you hit a brake drum

Hi, I've been rebuilding the brakes lately, but I just can not get one of the drums off. I'm now at a stage where the puller is now starting to bend and twist. I've tried heat,but I'm worried about heating to much. I've tried hitting it but am worried about hitting it to hard as the drums are cast. The last thing I want to do is crack or break it. How much heat or hammering can you do on these things? Any tips or pointers would be great. Luke.

It may already be deformed and junk. You didn't say what vehicle you are working on, but some had the lugs swaged onto the drum, and the drum will not separate until the swaged portion of the stud is cut.
If the puller is twisting, what are the chances that the thin metal part of the drum that goes over the studs has stayed flat and true? near zero is my guess.

hi, sorry not been able to get on for a few days as I've had problems with my PC. The truck I'm working on is a 1960 B102. The studs are built into the drum. The drivers side rear drum came off with not to much trouble, but this side I'm having a nightmare with. I would like to put some more photos up but I've lost everything from my old PC. It will probably be the weekend before i get to look at it now.
The previous thread to this one "braking problems" is the build so far, which has some photos on. Luke

it almost sounds like a taper fit for the drum on the axle. Is there a nut that you took off? If so, slow steady pressure with a puller. Push on the axle and pull on the studs. At least that is my thoughts.

Use of a torch to heat around studs. Then use hammer while puller is pulling. Keep heating. pulling and banging. Once drum is removed always file out lug holes so it will be removable in future. International rear drums all seem to have this hard to remove problem.

As was stated before, the studs are swedged into the drum, you really need a swedge cutter to properly take care of it.

yes it is a tapered fit. It also has a long spline key also holding it in place. i'll try and get some photos up as soon as i can. Thanks for the feed back.

here is the modified puller

This is the one i managed to get off with out to much difficulty.

Gave up on trying to get the brake drum off. Reconnected all the hoses and pipes and bled the system. I took it out for a test drive around the block and they seem to work fine, no pulling to the left hand side now. I have it booked in for an MOT test next Saturday, fingers crossed it will pass.