The Stewart-Mac reamer produced a perfectly centered hole in a short time -- it's not cheap ($58) and it wasn't quite large enough so look at the tuner shaft size when buying one you might need the large size ---- me I've worked as a carpenter for many years in the past and the finish reaming was no issue and I plan on 1 or 3 other Epiphone tuner upgrades so I've saved a bunch of $$$ buying this tool -- PS the tuner mounting holes to keep the tuners straight - buy the smallest drill bit you can find and pre-drill the screw holes and don't drill all the way through the guitar head