I sometimes use just one piece short bar of square stock 1/2sq works good usually.
File of mill one end nice and flat.
I sweat solder the bottom of the sight base to the flat.
Then as one piece I mount the bar in a vise and work on the sight base.
I already have the dovetail ends about fitted to the bbl dovetails, but the final fit waits till I'm done with the sight details.
The sight base sitting on that pedestal makes it easy to get at any area an detail.
When you are ready, just heat it upside down and the sight drops off. A little scraping or file work and any excess solder from the sweat soldering is removed.
Ready for final fit in the bbl dovetail.
Works well for other hard to hold parts too that like to run away and hide on you while filing and polishing.
There's usually enough solder left on the piece of bar stock when done so the next time all you need to do is flux the part, clamp and heat to sweat solder it in place.
I also use one of those small vises that clamps on to the edge of a table or a board sometimes. I have mine clamped to a short piece of 1.5 x 1.5. Then I clamp it by that in my engraving vise when I want to use it.
I do alot of gunsmith work at my engraving bench.
I cut a capture edge in both opposing jaws of that little vise at one end to lock the dove tail edges of sights in.
Just down from the top edge of the jaws.
That works pretty good too but you are limited by the vise jaws in completely filing and polishing the entire sight/part.
This is a pic of one,,not mine, but similar.
Very common both antique and modern.
Usually not expensive. Very handy to work on small stuff.
Get one where the vise jaws close up squarely so it holds the small parts good.
