Here's the front beam on my bench. The top adjuster is already in. Note that I'm measuring the lower adjuster with a pair of calipers, and I have positioned two hose clamps around the lower beam as cutting guides. I just used my Sear's reciprocating saw (aka Saws-All) to do the cut. I was careful, and just barely nicked the host clamps. I used a high speed grinder with a cut-off wheel to get the opening just right, and to angle (camfer) the edge to get better weld penetration.
Any areas to be welded were prepped to bare metal with a wire brush on the high speed grinder.