Installing Harrison Design's Snake Sights is a pretty simple procedure. Confirm that your revolver is unloaded and all ammo has been removed from the room. While no springs under tension are involved with installing Snake Sights, it's always a good idea to protect your eyes with safety glasses.
FRONT SIGHT
The old front sight is removed by inserting the supplied .050" hex key into the set screw that that is visible from the front of the sight rib, just above the muzzle. Loosen the screw by 2-3 rotations and the old front sight can be lifted straight up and out of it's pocket. Insert the Snake Sights front sight into the mounting pocket with the little set screw dimple pointed to the front. Insert the sight until it sits hard against top of the rib, tapping with a soft hammer if needed and filing a small amount of clearance on to the mounting post if it is tight in the pocket. When satisfied with mounting, if the set screw is still snug to rotate (indicating that the original loctite is still working) you may retighten the set screw.
If the set screw turns freely, you would be advised to remove the set screw from the front of the barrel and apply a small drop of LocTite 242 to the set screw with a tooth pick, then reinstall into the barrel and snugly tighten.
REAR SIGHT BLADE
To install the new Snake Sights rear blade, select a screw driver that is a proper fit in the rear sight's windage screw, accessible from the right hand side of the sight. Use the .050" hex screw to loosen the set screw in the old sight blade and then using the screwdriver, unscrew the windage screw (CCW) until the windage screw and blade come loose from the sight body. Before you remove the screw or blade look at the underside of the sight blade and note how the windage screw engages the sight blade. Remove the sight blade and screw and set the screw aside as it will be reused.
Just a few thoughts and tips concerning fitting the Snake Sight rear sight blade into the OEM sight body. First, because it is a dovetail assembly and the desired outcome is to have as little free play as possible, we've made the dovetail width slightly larger than OEM sight blades. Because of this, it takes some finesse to get the sight blade aligned with the sight dovetail and started straight into the sight body. On the majority of the sight blades that I've installed, no fitting was required. Some of the ones that did need fitting, just needed light sanding on the bottom of the dovetail along with chamfering the corners of the dovetail. A few had a bit more mismatch and required the front angled edge of the sight blade's dovetail to be filed some to fit.
A dial or digital caliper is really valuable so you can know where you started and where you are now when you start fitting. Measure the front to back width of the dovetail and write it down. Do the same on your old sight blade. Also measure the top to bottom dimension of the sight blade and record it. That way, you can see how far you've gone. If you are only .002"-.003" apart on width, then sanding the bottom should work. If you are .004" or more, I would file to fit.
Begin by test fitting the sight blade into the body without including the windage screw. You can wait about the screw until you have the sight blade able to go in and out. Don't give up and start sanding or filing away until you are really sure it won't start in. Try from both sides of the sight body. Use plenty of light and if you've got it, a magnifier to see that you are really lined up with the dovetails.
You don't need a really aggressive sanding grit. 220 - 320 should do it. You can only sand .003" or so from the bottom before the two pockets for the windage screw are too shallow. If you get to this point, you may have to file some on the angled surface of the sight body's dovetail. Just work only on the front side of the dovetail and again, it shouldn't take much. Hold the sight blade in a padded vise as shown in pictures and file as the picture indicates. Every couple of strokes, look at the surface and see that you are cutting evenly and not changing the angle of the dovetail. Color with a Sharpie marker and file another stroke or two, then recheck the surface. Remove from vise periodically and measure with calipers & re-test in sight body.
On the tips of each side of the sight blade's dovetail, there is a chamfer that is important to maintain if you wind up having to sand or file. Unless your vision is super keen, you'll likely need a magnifier to really see it. It's purpose is to just not have a sharp point on the edge of that dovetail, because in the female dovetail in the sight body, that corresponding corner will be rounded from worn dovetail cutters and a sharp edge will give a false tight effect as you are fitting.
Once you are able to insert the Snake Sights blade and can slide it in and out, remove it and engage the windage screw as noted earlier. Put a little oil in the sight body and in the two pockets on the underside of the sight blade that the windage screw engage. Slide the blade and screw in nested together and push them in until they stop. That point should be pretty close to the sight body. Then start turning the windage screw as you hold a little pressure against the blade and the screw will engage and push the blade in as it's turned. It should not take any torque to speak of to turn the screw. If it's hard to turn, take the blade back out and recheck the fit of the blade and also test the screw turning into the sight body by itself. If everything is going together as expected, turn the screw in until the sight is approximately centered and install and tighten the set screw. Adjust your sights as you would any other adjustable sights.
Once you have windage adjusted, you would be advised to remove the set screw from the sight blade and apply a small drop of LocTite 242 to the set screw with a tooth pick, then reinstall into the rear sight blade and snugly tighten. Do not use LocTite on the windage screw or the sight blade dovetail.
