How to enlarge a drilled hole without a drill press

I, like undoubtedly many others, have bumped into the problem of how to enlarge a drilled hole without a drill press.

Today I made a little roller board for my mitre saw and as a good engineer I measured the padded feet of the saw to the millimetre and drilled holes for all four feet that were 1mm larger in diameter than the feet.

Now you would wonder why this wouldn't be a great feat of engineering and just how it should be done, since the saw feet did fit perfectly into the holes. The catch is that in order to get all four feet into their respective holes you have to align the 21kg (46 pounds) saw perfectly to a board on casters...

So to make life good again I had to enlarge the holes from 26mm to 35mm to just drop the saw somewhere there-about-ish and be done with it. Unfortunately drilling free-hand with a drill-driver using a 35mm Forstner bit around an existing hole with no centre spike location isn't exactly easy - I'd dare to call it next to impossible.

Enter the world of good old jigs and a simple trick. Since guiding a driver with a Forstner bit free-hand is impossible you can simply make a guide-jig by drilling a hole into a piece of scrap wood with the larger bit and then centre the jig over the hole you are enlarging and clamp it down.

Insert the Forstner bit into the hole you previously drilled into the jig and rev the drill up before lightly making contact with the edge of the work piece  Use the guide-hole to keep the drill from wondering and you get tear-free ingress edges as a bonus since the jig works as a tear-out protector at the same time.