I would think that you would have better luck with a new hole saw, slow speed, and lots of lubricant. Less likely to grab a flute and launch your piece. If the 3/4 holes in the 2" tubing are for pivots, axle, etc. consider using a sleeve to provide more load bearing surface. https://www.ebay.com/itm/Steel-Tubin...itleDesc=0%7C0
With this you could just drill 1" holes in the tubing, align the bushings, and weld in place. This process could compensate for any "drift" in the drilling process.