Novak dovetail dimensions

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Koda94

New member
Can anyone tell me the nominal dimensions of a rear Novak dovetail groove for a 1911?

I have a pistol with a "novak style" (i.e. NOT novak) sight that is falling out and I want to replace it with a new rear sight. Can I just buy any novak sight and have it be the proper fit?

this sketch is the dimensions of my slide dovetail cut.
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Scorch

New member
FYI, there are a few other dovetail cuts that look like Novak's but are in fact dimensionally different. Kimber, CZ, and Para LDA are the first ones I encountered, but Taurus, Rock Island, and Springfield have used similar looking slide cuts.
 
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mulespurs

New member
Perhaps

Perhaps you could put a small shim under the sight to push it tighter in the dovetail. A cheap feeler gauge set would have one that would be the right thickness and about the right size.
On another note you could also use a center punch to put some punch marks on the top of the slide in the bottom of the dovetail cut. That method has been used for years to fill in a small space, like a worn shaft under a loose bearing. I would try the center punch trick and use some blue loctite if it was me. Good luck.
 
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tango1niner

New member
A good fix for a slightly oversize dovetail is to take a flat punch and tap the top or opening of the dovetail straight down towards the bottom. It is important that you do this a little at a time and "sneak up" on the desired degree of "tight" that you need.
 
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HiBC

New member
I can try.
First I have to get to the master dwg. Seems like Brownells or Midway has a ref page.And,you did give Novak info.
It would be geat if the gave the pin data,but I doubt they do.
If they have data that defines the dovetail,I can convert it to a pin measurement. The radius of the .093 pin (1/2 dia) is a key number.the dovetail angle is a key number. That's two numbers In trig,any two gets you the third. Make a nice sketch.Use a compass or some circle. If you have a protractor,great. The center of the pin dia represents one point of a triangle.The point of tangency where the pin contacts the dovetail is another.The pin radius is the length of a side. I'll help,but maybe you can try.

This will get you a trig cheat sheet PDF
http://tutorial.math.lamar.edu/pdf/Trig_Cheat_Sheet.pdf

This will get you to a BING image page with all sorts of dovetail measuring info

https://www.bing.com/images/search?q=dovetail+pin+measurement&qpvt=Dovetail+pin+measurement

You try.If you can't get it,I'll help

If you are going to do any peening,punching,etc to tighten things up(and that can work) I suggest you NOT beat up the gun's dovetail.Do your damage to the sight.
 
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K

Koda94

New member
the sketch I created above are the actual dimensions of my slide how I measured it. The resulting .504" is the as produced size of the dovetail.

The problem is the manufacturer is one of those companies that doesn't use original Novak sights, and they are not going to give anyone their proprietary size information.... Ive asked and they wont answer. Based on my actual dimensions my guess is .500" is their nominal dimension so my slide is toast. If they mimic Novaks dimensions its even worse. Brand new gun, I don't know what to do.
 
K

Koda94

New member
so my question now is what is the preferred nominal "interference fit" for dovetail sights? My guess is .0005" to .001"?
 
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Scorch

New member
Most sights have set screws that will allow you to make up for a little bit of looseness. Notice I said "a little bit". Many factory rear sights are very loose once you loosen the set screw.

Or you could TIG the slot and start over.
 
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HiBC

New member
Try this,from Brownell's

https://www.brownells.com/guntech/Novak-Dovetail-Installation/detail.htm?lid=16679

I entered "Sight Dovetail Dimensions" in my Bing search window. A whole bunch of places to go to came up.You can research them.

This link will take you to a Bing image page with scads of dovetail drawngs

https://www.bing.com/images/search?q=sight+dovetail+dimensions&qpvt=Sight+dovetail+dimensions

so my question now is what is the preferred nominal "interference fit" for dovetail sights? My guess is .0005" to .001"?
Click to expand...

Its really hard to put a dimension on the "feel" of a fit. If the form of both parts is(relatively) perfect,as in a reamed dowel pin hole,.0002 is tight interference.

Typically between a sight and the dovetail the "fit" is corner condition ot other hight spots that are minimal surface area and they(somewhat) swage to fit

Also there is often a slight taper to the fit.Its like saddling a horse,but backwards,as I recall. In and out from the port side.

If you have a witness line,and you just want the blinking sight to stay put,there are gap filling Loctites.

If your sight lacks a setscrew,add one! Add two!!A little drill and tap job!

Assuming your dovetail slot in your gun has not been roughly opened with a three corner file,that it is in good shape, its easy to buy more sights.
I'd leave your gun dovetail alone.
Assuming it does not rattle out,you han make a small cold chisel like tool maybe 3/16? wide? Give your sight good support and on the bottom surface of the sight gentle tap two rows of diagonal crosshatch "knurling" on the bottom of the sight dovetail. The interference of the peaks will swedge down on installation.Start shallow .You can retrace them and beat harder if necessary.
 
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Koda94

New member
HiBC said:
Try this,from Brownell's

https://www.brownells.com/guntech/Novak-Dovetail-Installation/detail.htm?lid=16679

I entered "Sight Dovetail Dimensions" in my Bing search window. A whole bunch of places to go to came up.You can research them.

This link will take you to a Bing image page with scads of dovetail drawngs

https://www.bing.com/images/search?q=sight+dovetail+dimensions&qpvt=Sight+dovetail+dimensions
Click to expand...
well those Brownelles dimensions makes my situation even worse. .488" is .007" smaller than what Novak shows on their website, which is .009" smaller than my as produced slide.

What I'm struggling with is deciding if I want to demand they make me a new slide, or let them custom make me an oversized rear sight which is what I think they are stalling me for.

This is a $1400 gun, what would you do?
 
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HiBC

New member
Its accepted practice to use a safe sided 3 corner file or other means to open the gun dovetail to fit a sight.
I don't have enough info/both sides of the story to comment on your gunmaker. You paid $1400 for something you are not happy with. IMO,the maker should work with you and make you happy.
Me? I'm not trying to make money. I do not have an FFL,I do not take on gunsmith work. I do my stuff.
I have access to a Bridgeport mill and an assortment of sight dovetail cutters. And sets of pin gauges. I also bought X_S Sight Systems little dovetail measuring tool.It takes pin measurements off the dovetail and the sights.

I'll make a little fixture to hold the sight upside down so I can mill the sight.That CAN be as silly as holding the flat bottom of the sight with a ground flat and square magnet and pouring a Cerro-safe nest. But ordinarily,I just need a step,for an alignment fence,a flat surface for most of the dovetail bottom to sit on ,and a clamp. Maybe 1/8 thick,steel flat ground is good.You load it in the mill vise with the sight hanging down,and one side of the dovetail can be cut. That's all you need.
I get about .001 oversize. Usually the sight will just start.I cut so the flat bottom of the sight dove tail bears tight in the gun.And the angled faces.
Then I can stroke the flat bottom of the sight dovetail on a flat file if I need a few tenths looser.I'm not looking for a number,I'm looking for that tight,but driftable fit.
Beware corner conditions. Break the sharp male corners a bit.

I take time and patience to fit it the slightly harder way,so that downstream there is not the problem you have.But I'm not normal!!

A lot of sights come a bit oversize. You might call a sight company with your dovetail numbers and ask if they will send you something that will fit,or give you a little steel to fit.
Some sight companies will let you send the slide and they fit it.

Putting steel back on....As Scorch said,its a TIG thing. I don't have that.

Don't overlook drilling and tapping the sight for lock screws.They work.
 
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HiBC

New member
Thanks,Scorch.That is great stuff.Learned a thing or two! Click the link and get the whole reference.
 
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