How big to cut the keggle hole?

I am acquiring a keg today, and I can't wait to get started making a keggle. I am going the cut the hole with my trusty harbor freight grinder. What I am wondering is why every keggle I see leaves a 1 to 2 inch rim around the top of the keggle. I am going to start with 5 gallon BIAB brewing, and it seems the rim around the hole will cause the bag to snag or rip. Also, it just seems cleaner to cut the entire top off and grind the edges smooth so it is more like a traditional brew kettle.

I can think of two possible problems with cutting the top completely off:

1) Increased boil-off (not too big a deal in my mind)

2) Affecting the structural integrity of the keggle (possibly a very big deal)

All advice is much appreciated.

The handles are incorporated into the top part of the keg. Otherwise I think because of the size of the grinder disc it'll always leave a lip because you just can't get in that close without cutting into the skirt with the handles.

I've seen many keggles with the whole top cut out, (ground flush with the sides of the keg), and heard of no problems with it. I have a rim on mine because of the reason backporchbrewery states....it's just too tough to get closer because the handle part gets in the way, and I don't care. The keggles with a "full" cutout, however, do look damn nice.

I've also seen people cut off the entire skirt on top, leaving only the handles, and no problems there either....so I'd say do whatever you want.

I cut as close as I could get the plasma torch to the edge, and now I'm seriously thinking about cutting everything except the handles. I have seen them that way and I kind of like it.

I think it would still have plenty of volume and be lighter to lift as a bonus.

This guy cut the top off and left the handles, looked like it remained pretty strong.



VB