Here is a quick set-up to show how I have repaired a snare shell that was out of round. I have done this with a Brass shell as well, but this is the first attempt with a steel shell.
Ok - so...the technique is to stabilize the part of the shell that you dop not want affected. Then, tighten the rod that is threaded through the point on the shell at the oblong opposing ends. Most holes (use lug bolt holes) will require 1 1/4 inch thick rod. The technique is to tighten beyond the desired point. Then release pressure and check it again. Get a sense of how far to go first before you really go too far. I went too far with this steel shell, but I was able to take some more lugs off and repair it back to where I needed to.
When I did this with a brass shell, it required going further beyond the desired point compared to the case with the steel shell.
Take your time with this, but don't be afraid to do it. It is not that hard to do if you just use your head and think through what you need to do.
Great success every time I have had to do this.
Pointer: When stabilizing the in-round portion of the shell, tight up the nuts on the rod, as if you don't, it may cause it to become unstable and to bend on you. Then it is not doing its job anymore. No need to tighten it up too far (making your good edge OOR too) - but get it stable/tight.
[ame]http://youtu.be/lAieEhS8wyQ[/ame]
Yes, this needs to be done before you try to get a good tuning out of your snare. Certainly get this addressed before installing new heads. Heads seat (correct term?) to any edge permanently more or less. Likewise, whenever bearing edges are modified on wood drums, new heads will be required so as to avoid head buzz.
Another note: Cut a slot into the end of your threaded rods so you can use a flathead screwdriver to keep it from turning on you as you tighten your nuts.
Anybody else try this threaded rod technique?