I use an 8" grinder, i made my own wood jig which lasted a while and was OK but wood is not really accurate to set your angles.
In a fit of madness a few years ago I bought a welder to fix some gates, so I decided to buy a few scraps of steel and made my own jig (as the bloke on eBay ignored my message).
The steel bits cost me £6 and I have LOADS left
It is not rocket science, good fun to make and nothing gives you a sense of satisfaction like making you own tools. Any other bits you need like tap & die sets don't need to be expensive and you will use them again (in wood/Corian/acrylic).
If you have a mate who welds or you can borrow a welder even better.
And I must stress I am NOT a welder, never done it before, it looks awful but it works really well. All the bits cut by hand with a hacksaw (hard work).
I just copied some pics of other models.
Tools like taps, dies and welders are an investment in future projects not one-off tool purchases - sell that to the wife!
Let me know if you want a pic (but it's not pretty)