Don't......

I would be looking for some one who can and has done it with no issues , you only got on kick at the can and then it's ruined for ever!

Latindrum on Drumsmith did his with a 2 by 4 and a hammer.

He mentioned some out of roundness after the initial banging, but said it was corrected.

I thought I was getting a brass Gretsch shell from ebay with no beds.

Luckily, it showed up with beds installed.

I was thinking one would need a rounded jig to hold the shell in round on the outer shell. Then maybe a rounded edge 2 by 6 to be slipped inside shell, tight, again to hold it in round.

Gentle tapping with a wood block.

I believe the main problem with tapping on a shell is keeping it in round with no deflection. Thus the tight support in and out of the shell.

A special pair of large vise grips is also in my mind. Still not sure of any of this.

Probably done in a custom press at metal shop.

Perhaps a metal fabricating shop could provide info.

I would love to know how it is done.

Please let us know.

SA

I've seen quite a few shells where this was attempted, all were messed up. (Metal is unforgiving). You could talk to a pro drum maker, but to do it right would take experience, & machinery. Seems that paying a knowledgeable pro would be the best route.

Straight walled shell? Filing a bed would be your best and safest bet. Be sure there are no burrs left behind by fine sanding/grinding that could cut the head.