All of the projects and plans you see that use a threaded bolt for adjustment or tightening calls for inserts. I never have an insert when I need one and I’m not great for planning projects ahead of time. In most hardwood, just threading the wood will suffice. Choose a drill bit one size smaller than (about 1/16”) the size of the bolt or screw. If in doubt, go small (within reason). You can then thread as if you would any metal piece, but cutting oil isn’t required.
Don’t have a tap and die set? Take a bolt or screw the same size and with a file (use a triangular file or the corner of a square) cut a groove perpendicular to the threads. Use this for threading.
I have even just forced the bolt into a slightly smaller hole, but this tend to provide a little to much tightness for some applications.
Worst case you find out the wood will not hold (this has never happened to me) and you add an insert. Give it a try and let me know what you think.
Hope it helps
-- Master hand plane hoarder. - http://timetestedtools.com