After removing the existing front sight - either by unscrewing it using the proper 3/16 hex tool (NOT your Leatherman or some other grossly inappropriate tool) or driving it out with a punch (for the plastic stake in sights) - thoroughly degrease the front sight hole with acetone.
Next, degrease the entire front sight with acetone, paying special attention to the exterior and interior of the threaded mounting post on the underside of the sight. The threaded post is made to standard OEM supplier specs, but you may find certain Glock slides to be thinner at the front hole and allow more of the post to protrude than desired. This will cause the set screw to bottom out on the post, and not on the slide itself. The correct solution here is NOT to try to tighten the screw more, as you risk snapping the screw head off and ruining your front sight. The CORRECT solution is to file off a little bit from the post so that it sits just below flush of the slide, allowing the set screw to tighten against the slide.
Next apply a generous amount of blue Loctite 242 to the entire bottom of the front sight, inside and outside the mounting post. When you press the sight into the slide, you should see blue Loctite squeeze out around the whole blade. The sight hole in the slide is subject to a great amount of variation, and many are a bit rounded off. The Loctite will help take up any rotational slop once the sight is installed.
Next you need to get the set screw started in the mounting post. I use a set of tweezers to do this.
Next I lay the top of the slide, upside down, against the top of a vise. The smooth jaws are taped off to prevent marring the sight blade.
Gently tighten the vise to hold the front sight in place. Move the slide so that it is parallel to the vise jaws. You have now straightened out the front sight, aligning it to the slide. Using this method improves the overall alignment, as you are using bigger reference lines than just the sight blade alone. The set screw is also positioned for final tightening.
Wipe off the excess Loctite with a dry rag, and set the slide aside for a few hours so that the Loctite sets properly.
For the rear sight, start by firmly clamping the slide into a set of padded vise jaws. Do not overtighten and crush your slide! Using a drift punch, remove your existing rear sight. Now to test fit your new 10-8 rear sight.
The Glock slide dovetail is hourglass shaped, and basically funnels the sight into a small tight spot in the center. Our sights are dimensioned so that they are a snug fit in most Glock slides. Press the sight into the dovetail, it should stop with finger pressure about halfway into the dovetail.
Using a nonmarring drift punch, like the ones I offer on the webstore, drive the sight into the dovetail.
Center the sight on the slide - you can eyeball it or measure each side of the rear sight relative to the edge of the slide. Now flood the screw hole with Loctite 242 and install the screw. The extra Loctite helps tighten the fit. It may seem crude, but remember we are installing combat sights on a gun which is half plastic. We are not building a Holland & Holland double rifle here, and the Loctite helps with the various tolerances we will encounter. When you sight in at the range, you will still be able to move the screw and sight as needed, though you may wish to add a light dab of Loctite to the screw once you are finished. If you wish, you can also reserve the Loctite application until after final sight in.
Wipe off the excess Loctite, let it set for a few hours, and you are now all set!
