Need rough estimate on costs to machine aluminum part...


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Jim March
April 1, 2003, 03:51 AM
Hi all;

Night sight sets for the AR15 are common as fleas, and fairly cheap. This Trijicon setup is classic:

http://www.impactguns.com/store/media/tri_ar15.jpg

Source: http://www.impactguns.com/store/trijicon_cp25.html

The question I have is, how much would it cost to make a sight rail that would hold those parts, for a typical fixed-sight revolver?

http://www.ninehundred.com/~equalccw/sightrail.gif

Elevation is adjustable via the front screw at the bottom of the sight, just like...well, like an AR15 :). Windage is a matter of shimming the rear within it's "fork". The flat spring causes the sight to resist flipping from one apeture size to the other but it can still happen whenever desired.

OK, it's weird as hell...but it'd work GREAT :). Right? :D

Question is, purely a rough estimate, how much to actually fabricate that rail? If it cuts costs, the various "curves" shown can be done in a more angular fashion, although "organic looking" curves would look better I think.

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HSMITH
April 1, 2003, 11:17 AM
1 is going to break the bank. You will pay at least $400 for one, and that would be getting off very cheaply. I would think you are going to have a hard time geting one made for less than $800, unless a machinest member here chooses to help you out. If you made detailed drawings including all angles, radii, sizes, etc it will cut the cost too. If you could get 25 guys to sign up for one the cost per is going to drop drastically, like $50 each or so.
If you go to get it done stay away from the gunsmiths, go straight to a small contract machine shop. If you need help finding a machine shop let me know.

Jim March
April 1, 2003, 01:52 PM
Right. Hmmmm.

Couple things:

Besides the one I want for myself in a few months, does anybody think there might BE a market for these? Tritium ghost-ring sights for Glocks and such sell a fair amount, and run about $175; the Tritium AR15 parts are about $70 so if this rail ran $100 to $150, the net value wouldn't be bad and you'd get some interesting advantages.

At $50 retail with something closer to bulk manufacturing, it'd really ROCK :).

DT Guy
April 1, 2003, 03:12 PM
Not sure (don't have a picture in front of me) but might it be easier/cheaper to modify an Aristocrat or Power rib to do this?

AFA finding someone, go to the Roderus home gunsmithing forum (Pvt. Ryan's site) and ask around. Some talented machinists over there who might be interested in doing something like this.
Roderus Custom Gunworks (http://www.roderuscustom.tzo.com/cgi-bin/ib3/ikonboard.cgi)

Larry

jrhines
April 1, 2003, 05:01 PM
Jim - PM me & we'll talk.

Jim K
April 1, 2003, 08:55 PM
Hi, Jim M.

Yes, a one-off would cost more than if there were some quantity order. But I will say that I have had more complex pieces made of steel for a lot less than $800. I think I could probably make that mount in a couple of hours, but I really don't want to tackle it.

I agree with HSMITH both in doing a good engineering drawing and in using a small contract machine shop. You should also consider simplifying the shape; those curves, as you say, look good, but will be costly. I would look around and see if there isn't a sight that can be adapted more easily.

Also, the more you can do yourself the better. For example, if you can drill and tap the holes you will save bucks.

Jim

Jim March
April 2, 2003, 02:25 AM
Looking again, first obvious issue is that the rear "fork" has to be raised some more to clear the topstrap. No biggie. And none of the dimensions are really final until I get the actual AR15 parts plus measure the barrel diameter, topstrap dimensions, etc.

It might be possible to eliminate the outer curves entirely, if the "fork width" can be at the same width as the main body of the rail. That would make the rail basically the same width as the barrel.

<scratches head>

I realize some of the curves are complex...the inside radius on the "fork" isn't so bad, that's just a drilled hole but...the outside curves on the fork, and how the whole rear fork thing "rises" would be annoying...

As to modifying an existing rib - I found the Bo-Mar stuff online:

http://www.bo-mar.com/kevi_004.htm

The bottom-most part has some possibilities. With the adjustable rear Bo-Mar sight completely removed, there might be enough in the "middle" to act as the "fork", drilling horizontally through for the pivot pin.

But it would still be a big pain, front and rear. And worse, the Bo-Mar rail is *heavy*, 7.5oz on a 6" barrel, clearly made of steel. I'd rather have aluminum, I assume it would be easier to machine and wouldn't need a finish other than a mild polish.

Does anybody think there's a *market* for such a rail that would allow AR15 multi-apeture rear sights and whatever AR15 front you wanted?

HSMITH
April 2, 2003, 10:20 AM
Just for my information, have you held a block of wood or something else (mockup) out at arms length with the AR sights in it? Seems to me that the aperture would be WAY small for shooting with arms extended, and the post would be rather large since it was designed for a 18"+ sight radius. Just curious is all.

Desert Dog
April 2, 2003, 11:02 AM
I will reiterate what others are saying. If you can make blueprints with accurate dimensions, you will save a lot of $$$ in the initial cost of the part.

The other issue is all the cuts that will be required in its current design. The killer cut though is the radius for the barrel... that is probably going to be the most tedious part of this manufacture, as the barrel typically tapers down toward the muzzle... It will also be different for each revolver type or make.

Mike

Jim March
April 2, 2003, 12:59 PM
HSMITH: I've done two things: held some typical (admittedly non-Tritium) AR15 sights at arm's length, and compared the apeture diameters to those of typical current handgun ghost ring sights (1raggedhole, various types for Glocks, etc).

As to the first, I shoot from a Weaver hold so the eye-relief distance isn't all that different, at least in terms of length to the rear sight.

As to that curve on the underside, yup, I already thought that would be a pain.

What if we did something else entirely? A squared-off underside cut, in profile like so:

http://www.ninehundred.com/~equalccw/sightrail2.gif

Now it works with any barrel diameter, and even a mild taper would only mean a slightly different elevation adjustment, right?

jrhines
April 2, 2003, 02:41 PM
Jim - So far what you are describing is pretty rudimentary as far as machining goes. Using a small CNC rig (like the one in my basement), and given the dimensions and a free hand in design mods, the whole thing should be just an evenings work. As for finish, my choice would be flat bllck powder coat. Cost, the first one you can't afford, but the materials would run maybe $65.

Jim March
April 3, 2003, 02:18 AM
Well lookit: if somebody thinks this concept can *sell*, we can write a contract saying that the first will be done as low cost as possible, then reviewed online and as more orders came in, the machinist who did the first would get an exclusive on all subsequent.

So a key question is, will this sell?

Lemme show y'all something:

http://www.gunsamerica.com/upload/976328499-1.jpg

That's a Freedom Arms "97", which is very close to the same heft as an original Colt SAA. Very nice gun, worth about $1,300 minimum although that specimen with an octagonal barrel is more.

Look at the sight; it's fully adjustable but there's more to it than that. Compare with this Ruger fully adjustable sight Blackhawk single action:

http://www.gunsamerica.com/upload/976323749-1.jpg

What's wrong? The rear sight is too far back for "fast thumbing" of a Single Action, especially if you're cocking by throwing your thumb knuckle over the hammer instead of the pad of the thumb - the pad will tend to "hang up" on the rear sight blade with painful results.

The solution? Start with a Vaquero, ditch that silly "half a dime" 19th-century front sight, and drop on a whole new modern setup that beats the Blackhawk factory setup for both flexibility, effectiveness and it AIN'T NEAR THE HAMMER :).

Call the result a "Streethawk" or something :D.

It's not just for CCW; you also get a faster-handling gun for woods defense against bear (in 44Mag, 45LC+P or some wacky wildcat) and again, get faster draws than a Blackhawk but without giving up anything on the sights effectiveness.

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