(05-14-2019, 05:28 PM)Admiral Wrote: Dremels are lightweight tools. You might be better off going to a Harbor Freight and getting an air tool grinder and some bits.  A bench grinder, used judiciously with a vice grip, may also help with finishing off with a file.  A good mill file will also make short work of this if its sharp.

(05-14-2019, 12:11 PM)daddo Wrote: >>>>  The angle grinder is of course to big. Forget the bench grinder.

Why is the angle grinder to big?  Is it too unwieldy?

I'd be experimenting with securing the angle grinder, effectively turning it into a bench grinder with a very narrow wheel.   Make a holder using a 3/8" nut, to give you a handle to hold the thumbscrew as you dress the welds.  It's much easier and safer to be manoeuvring a small handle than a cumbersome angle grinder.

For a really fine finish, I'd follow up with the little drum sander attachments that you can use in a Dremel or even just run in your drill press.   Even a good wire brush in the angle grinder will give you a lovely satin finish.  In fact, that would probably be my preferred method for final finishing.

Having said all that, I would prefer to use Willyou's plan of the slotted bolt and the silver solder.  If your fits are within small tolerances, the thin bead of silver solder would not be an aesthetic problem at all.  I'd even have a go at using the same method, but brazing instead of silver soldering, if cost is a factor.  Using the wing inside the slot means that one is not relying on the welds for strength, but only to secure the wing in the slot.  You are simply using the wing as a screwdriver. There will be some additional strength from the weld, but it is not the major contributor.   You could probably even just epoxy the wings into the slots.