I know that there is the brute force method of hammer and punch and then there was the $120 gizmo I found online. Has anyone come up with something else that is cheap, effective, non-destructive and easy?
Pistols = field strip and chuck slide up in a padded vice. use a hammer and a punch to remove the sight from left to right (relative to the muzzle pointing away). The key is to completely immobilize the slide so 100% of the driving force is transmitted to the sight. and keep the punch agains the base. Reinstallation of new sights is best and most effectively accomplished with a sight pusher. Its precise and doesnt break ther expensive tritium vials inside todays night sights. Reinstall from right to left.
Rifles = Hammer and brass punch to remove and replace, drift from left to right to remove and reinstall in reverse. It also helps if you clamp the rifle into a padded vice. although rifle sights in dovetails are generally alot easier to move than pistol sights, which is why you dont need a pusher to do rifle sights.
If you do alot of high volume sight work as I do. You will need a method that is fast and effective. I modified my heavy bench vice to push sights, as well as clamp the slide for removal with a hammer and punch. I drift them off and reinstall them in one fell swoop.
Make sure you MEASURE each side of the sight base before you drift some are ONE WAY ONLY.. Also make sure you have looked to be sure there is not a set screw holding it and if so remove that first. Make sure if using a punch it is BRASS if your keeping the site to use again I recommend a layer or two of masking or electric tape to keep the metal transfer down to a min. If you can not drift it without a sledge lube it let it soak then try again.
Also it is ALWAYS a good idea to cover the are surrounding the dovetail with a few layers of masking tape while removing and installing the sight just in case you slip with the punch or hammer.
What type of sight, and what's it mounted on/in? For the standard 3/8" dovetail arrangements - Marlin 336 or Winchester 94 for example, I clamp the barreled action in a padded vise, with the sight's dovetail pretty much centered in the jaws and level with the top of the jaw, then use a 3/8" hard maple punch going from left to right to break the dovetail cut's grasp on the sight. From that point it's just a matter of fairly gentle tap-tap-tap till the sight slides out. I've found the hard maple to be tough enough for this sort of thing, but being softer than metal it's more forgiving. Best part, I've lots of maple scrap, and can fashion punch shapes as required for just about any task.