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Fitting and Installing Dovetail Sights




NYECOGunsmith

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#1
When working on guns, keep the old gunsmith's adage in mind, always do the most work on the cheapest part!
Have a big meal, a good nights sleep, drink lots of water, and visit the restroom before reading the following long dissertation, you have been warned.

So, with dovetailed sights, you are going to do the most work of fitting them on the sight itself, on the tail of it, NOT the dovetail slot in the slide.

Tools you will need:
4 or 8 ounce Ball Peen Hammer
Vise with jaws padded with wood, leather, thick cardboard, or carpet.
Drift punch, brass or nylon, about 1/4" to 3/8" in diameter
3 cornered (60°) triangular file, preferably with one safe side and/ or triangular hard Arkansas stone
Wet/ Dry sand paper in 120, 200, 400 grits, or close to those three grit sizes
Small block of something hard and flat, like a block of steel, block of hard wood or MDF, thick piece of tempered glass, etc. it has to have as flat and smooth a surface as possible and needs to be about 4 inches square or larger.

Nomenclature:
These are the names of the parts of the dovetail sights as I was taught them, others may know them by other names, doesn't matter what we call them, as long as we understand what part we are referencing.

On the solid triangular portion of the bottom of the sight, that's the "TAIL" of the dovetail, although a wood worker making dovetail joints might call it the "PIN" gunsmiths usually call it the tail.
The tail has a BOTTOM, , that flat surface it rests on , and two sloping "SHOULDERS" that slope at whatever angle the manufacture made them for, usually 55°, 60°, 65° or 70°, with the 60° angle of the slope being the most common, and the easiest to acquire files and Arkansas stones for.

The dovetail SLOT has a "FLOOR", that's the bottom of the slot, and two sloping "WALLS". The walls normally run perpendicular to the axis of the bore, as does the bottom of the slot. In other words the slot, floor and walls run from one side of the slide to the other at (Hopefully!) a 90° angle to the axis of the bore.

OK, now that we are hopefully on the same page, lets get started.

With the slide securely mounted in a padded vise, but not squeezed so tight that you change the dimension at the rails!, and with the top of the slide and the bottom of the dovetail in the slide just BARELY above the top of the vise jaw, and the muzzle end of the slide to your left, use a brass or nylon drift punch and a 4 to 8 ounce ball peen hammer to drive the existing front sight out towards the right of the slide.

Then do the same with the rear sight.

Examine the now empty dovetails with a good bright light, and if needed , a magnifying glass.

Put the light on the left side of the dove tail, and look for burrs or irregularities in the floor and walls of the dovetail.
Now put the light on the right side of the dovetail and look slightly into the light to see if you see any shadows of burrs, etc. that you couldn't see while looking in the same direction the light was shining in at first.
Now take a Q-Tip® and run through the dovetails to see if it catches on anything your eyes didn't detect.

If you find any burrs , irregularities or obstructions, clean them up with a hard Arkansas stone (preferably one of the 60° triangular ones) or a small 60° triangular file, going slowly with either one and removing as little metal as possible.

If using the file, I recommend grinding one side / face of it smooth , no teeth, to make a "safe" side. This will let you rest that safe side against either the floor or one wall of the dovetail and only remove metal on one surface with each stroke of the file, not two surfaces.

Once the dovetail is in good shape, you are ready to start fitting the sights.

Dovetail sights should slip into the dovetail freely for the first 1/16th inch or so, then with a good bit of thumb pressure, should go 1/2 to 2/3rds of the way across the width of the dovetail slot and stop.

The last 1/3rd of their travel, to center them up, should require a drift punch and a hammer. This ensures you can adjust the sight, and that it will stay put wherever you set it.

So try the sight in the appropriate dovetail, and see how close it comes to the above.
Odds are it won't go much beyond that first 1/16th of an inch or so, because new dovetail sights are pretty much always supplied OVERSIZED so that they can be fitted perfectly.

And being the cheaper parts, we will modify them to fit the existing dovetail, not t'other way around!
And if they slip all the way into and maybe even out of the dovetail, indicating that it is too large as is, well,
we'll deal with that further down below.

Fitting the sight tail to the dovetail, now that's where that block of something hard and flat and smooth , and the wet/dry sand paper comes in.

Put the 120 grit sandpaper on the block of whatever, hold the sight between your thumb and forefinger, press the base of the sights tail down flat against the sandpaper and the underlying flat block, and make figure 8's with the sight. Of course the larger the figure 8 you make, the more metal is removed with each figure 8, so you have to make less figure 8's if they are a foot tall than you do if they are only 2 inches tall, and subsequently you would stop and try the sight tail in the dovetail slot after fewer figure 8's if you are making big 8's versus little 8's.

When in doubt, stop and try more often!

Making the figure 8 gives you a nice flat bottom to the tail, whereas if you just went back and forth, side to side, you will end up with a taper on the bottom of the tail, and probably rounded corners on it too, and we want it nice and flat bottomed and with sharp edges on the corner! Those sharp edges help it to dig into the corners on the dovetail slot and stay in place, that plus the pressure between the shoulders of the tail and the walls of the slot that is.

So you make a dozen or so figure 8's and try the fit, not there yet, go back and make a dozen more. Or whatever number you have decided on, based on how much the fit changed after your first pass at the sandpaper, and the size of the figure 8's you are making on it.

When it starts to go in to the point that it will slide in with thumb pressure about 1/3rd of the way, switch to the 200 grit, when it starts to go in a bit more, switch to and finish up with the 400 grit until it slides in with strong thumb pressure about 1/2 to 2/3rds of the way across the dovetail slot and then drive it the rest of the way with the brass or nylon drift punch.

We want a nice, polished bottom on the tail, for smooth sliding , and nice sharp corners on the edges of the tail and good upward pressure on the shoulders and walls.

Go slow through all the above, lots of figure 8's and lots of trying, don't expect to do this in 5 minutes, DO NOT take a file to the tail to file it down, or a Dremel® tool, I guarantee you will fork up the sight! Even after 60+ years of working with files and Dremel's on guns, I still do it with the wet/dry paper and by hand, and I have yet to screw up a sight doing it this way.
DO NOT try to enlarge the dovetail slot with the file. Yes, it can be done but takes a steady and careful hand and eye to get it right and straight, better to work on the sight, or order a sight with a smaller tail if it is grossly oversized!

Repeat for the other sight, then go to the range, use a rest, and get the sights where you want them.

Now what if the dovetail slot proves to be too large for the new sight?

Two options.

Order a sight with a larger tail, or, if the difference isn't huge, you can take a prick punch and put a single punch mark in the center of the dovetail slot, centered both for width and length, and see if this raises up the tail enough so that the shoulders on it make solid contact with the walls of the slot.

IF it does, then you put a punch mark on either side of the first one, equally spaced, and try for the same amount of depth of marks, then fit the sight as described above.
The three spaced divots raise the floor of the dovetail, and so lift the bottom the tail upwards, forcing the shoulders of the tail into the walls of the slot, and by sanding the bottom of the tail, you get that fit just right.

That's about it, take your time, and it is an easy task, and you save an hour or two of gunshop labor rate.
 

MAC702

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#2
Speaking of dovetails, does anyone still use a system like the Mann-Neidner tapered dovetail bases that attached the Winchester A5 scope to M1903 sniper rifles in WW1? The dovetails were in line with the bore and tapered such that recoil just kept them tight.
 

NYECOGunsmith

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#3
I think Steve Earle Products still offers the rings to fit the Mann-Neidner bases , you might see if he's still in business and offering them.
 

MAC702

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#4
They do, as well as ring plates to custom machine for the tops.. I was wondering if other rifles used the design. Seems useful.

I remember doing my first dovetailed front sight replacement on a 1911 pistol. A $20 sight was a lot of money, and the pucker factor was high!
 

NYECOGunsmith

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#5
Not many factory rifles were offered with the Mann-Neidner style tapered dove tails as I recall, I offered them on the custom rifles I built if the customer wanted them, they are a bit of a pain to machine as you might imagine.

I don't know of any factory rifles today that make use of them. At least I should say the Mann-Neidner taper style, there are EGW Bomar tapers out there, and Sako offers a tapered mount like this, but they all have their own proprietary taper angles as I recall.
 

TexasJackKin

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#6
I remember doing my first dovetailed front sight replacement on a 1911 pistol. A $20 sight was a lot of money, and the pucker factor was high!
I built my first 1911 when I was in high school (the good old days) working part time for $1.65 per hour. Everything was a lot of money, for me, in those days, I’m very familiar with the “pucker factor”
 

NYECOGunsmith

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#7
Yup, pucker factor is always there, no matter how many times you do something like this.
Went to work in that gun shop, that I ended up inheriting, when I was 5, the two old gunsmiths (life long friends of my Dad's), one a retired Master Tool and Die Maker, the other a 5th Generation Master Gunsmith and custom gun builder, started teaching me the trades right off the bat, but even simple chores like sweeping and dusting caused a pucker factor, because I didn't want to let Pop, or those two, down by screwing up.
Sweeping and dusting paid me a nickel an hour (not bad for a 5 year old in 1953!) when they started teaching me the trades, rose to a dime when I was actually learning something.
By the time I left for the CORPS was making $1.25 an hour!

It only got worse as the years went by, working on all types of guns, cheap or $$$$$, didn't matter, there was the fear of screwing up something someone else built. It's a wonder I didn't end up a nervous wreck, needing therapy...….oh, excuse me a moment, the other voices in my head are arguing over that and I need to cast my vote as the tie breaker...….

By comparison, stepping out of a plane at 40,000 feet for a HALO jump had no pucker factor at all, the only person who would be affected by my screwup at that point would be me, and I never gave a poop about him! :devilish::ROFLMAO: