User Panel
since the FSB can't be modified easily the only parts left to modify would be the front sight post and spring and detent.
maybe the front sight base post can be turned to smaller diamer and have the notches recut. along the same lines, maybe a smaller spring/detent can be used. something like the a1 spring and detent for the rear sight. by reducing the size of both of those things, you should be able to pull the front sight post into a smaller package. |
|
It seems to me that if there was a little bit of material machined off of the mold, it would result in more metal being left on the raw casting. This should be correct, since the casting is an "imprint" of the mold. How hard would that be to do?
|
|
Can we just thread the FSB and leave out the detent.
I mean it is a prototype. Who is to say that the FSB had a detent during the prototype phase. That would work for those of us not interested in daily shooters. Might be able to fabricate a non-detent front sight post. |
|
Quoted:
It seems to me that if there was a little bit of material machined off of the mold, it would result in more metal being left on the raw casting. This should be correct, since the casting is an "imprint" of the mold. How hard would that be to do? I'm actually going to talk to the foundry on Monday to see about this option. The order has already been placed for 200 parts, and they were given the go ahead to move forward. The foundry ran 8 test castings for me to check out before the full 200 were poured, and we found that a new shrinkage point occured after adding the second gate to the mold. The owner of the foundry assured me that we could fix the shrinkage by adding a third gate to the mold. If they haven't already started pouring the 200 piece order, maybe I can get my hands on the mold and work it over with a dremel tool. My only fear is that I'll booger it up and then it will look like crap. I'll know more when I call on Monday. If we can do that the problem is solved, I'm just afraid that I might be too late to change the mold. |
|
Quoted:
Can we just thread the FSB and leave out the detent. I mean it is a prototype. Who is to say that the FSB had a detent during the prototype phase. That would work for those of us not interested in daily shooters. Might be able to fabricate a non-detent front sight post. This is one of the solutions that John Thomas suggested. His thought was to use something like loctite to hold the thing in place. Does anyone really know if the original prototypes had detents on the front sight post. |
|
Here’s my suggestion if they cant alter the mold….
Eliminate the plunger and spring. Replace them with a small set screw that’s about the same diameter of the plunger tip. It would stick up and engage the notches in the front sight. The taped hole would only have to be about 1/4 deep. Adjust the sight at the range, then locktite the set screw in place. |
|
Quoted:
Here’s my suggestion if they cant alter the mold…. Eliminate the plunger and spring. Replace them with a small set screw that’s about the same diameter of the plunger tip. It would stick up and engage the notches in the front sight. The taped hole would only have to be about 1/4 deep. Adjust the sight at the range, then locktite the set screw in place. You just might have something there with that idea. |
|
Quoted:
Here’s my suggestion if they cant alter the mold…. Eliminate the plunger and spring. Replace them with a small set screw that’s about the same diameter of the plunger tip. It would stick up and engage the notches in the front sight. The taped hole would only have to be about 1/4 deep. Adjust the sight at the range, then locktite the set screw in place. I could live with that. |
|
It's quite late for me so my brain is about machined out for the day. If you still have troubles in the morning, I will check then. Otherwise, a cursory ( emphasis on curse) examination of your problem would reveal that your dies need modifications. Hopefully you have not had all of them cast so your bill is in the mail. The product does look appealing though!
|
|
OK I did just burn a brain cell and examine your problem. The problem as I see it, is that the area that would be machined to accomdate the site post and detent were made the same size as those that you would find in a conventional FSB, but the rib that makes the edge, is MUCH thinner so you would need to make the other area bigger to allow machining for the post and detent. So if your asking, should we make this bigger? My answer is a question, should we make this functional? The answer is plain I think, yes, you should.
|
|
If they haven't been poured, that would be an easy milling set-up for a machinist to increase the width of the cavity in the mold halves.
If they have been poured, I'd rather we simply use a site pin and no detent, If I use mine on a shooter and it moves beyond a simple blue/242 loctite fix, I would have no issues with drilling the front face for a 4-40 setscrew to touch the threads. It would look like a toolroom/armorer modification. |
|
200 parts at a buck a casting? Change the molds.
200 parts at 10 bucks a casting? Change the molds. 200 parts at 100 bucks a casting? Find a new foundry and change the molds. |
|
My biggest concern with altering the mold is... it seems the texture where you removed metal would not have that "sand cast" look/texture as the rest of the mold and it would be very obvious where the alteration was done.
Another suggestion I had was to move the front sight post rearward and eliminate about half of the threaded shaft from the bottom of the sight post. This way, we could drill a much shallower hole further back. Obviously, this would have an impact on the amount the sight could be adjusted. John Thomas |
|
Probably the all around best solution would be to modify the molds.
For match rifles in "service rifle" class, they generally extend the front sight hole and threads all the way through also so they can use a set screw inserted from the bottom of the hole to positively lock the front sight post into place after initial adjustment. I don't personally get the utility, but, all the big boys do it like that so I do too. Service rifle shooters are herd animals. Moo. Eat mor chiken. Anyway, I know that might be visually objectionable, but, would work. A set screw used in place of the detent pin might also be seen as visually objectionable depending upon whether you're looking at the top or the underside of the area in question. I'm thinking for my purposes, I'll most likely zero the front sight for elevation, lock it down using whatever provision is eventually provided, and forget it. If the mold cannot be modified without major trouble and/or expense, I'm thinking leave out any provision for detent pin altogether, and blue locktite the front sight post after zero. Or possibly, just use a small blind pin in place of the detent that could be set (edit to say, "permanently set") in place after zeroing the front sight post. I mean, how often to you mess with the front sight post anyway? |
|
Quoted:
My biggest concern with altering the mold is... it seems the texture where you removed metal would not have that "sand cast" look/texture as the rest of the mold and it would be very obvious where the alteration was done. Another suggestion I had was to move the front sight post rearward and eliminate about half of the threaded shaft from the bottom of the sight post. This way, we could drill a much shallower hole further back. Obviously, this would have an impact on the amount the sight could be adjusted. John Thomas John's concern with modifying the mold and loosing the textured cast look is my fear with changing the mold. Another fear is that the production run has already been poured or is in th process of being poured. I will find out more on Monday when I call the foundry. |
|
Looks like you could put the extra material on the front strap or webbing, it looks a lot thinner than the stock FSB, this area looks machined or belt sanded, so the mold change texture wouldn't be a big deal.
|
|
if you sandblasted the mold after modification wouldn't that even out the surface texture?
|
|
If you already have done the parts run, the easy solution is just to tap and drill for an AK front sight post. it uses the spring action of its legs to be retained, and doesn't require a detent or spring.
Apex gun parts has them for $2 each if I recall correctly. |
|
Quoted:
if you sandblasted the mold after modification wouldn't that even out the surface texture? I'll ask that question when I talk to the foundry. They do make molds for people who don't have one, so they will have the equipment to modify the mold. I seem to remember the owner telling me that they media blast the parts after the gates are removed. That is why they have a brighter look than the first test casting that Jess had done. Maybe I'm worrying about something that won't even be a problem. Again, this is all dependant upon the whether the foundry has started the production pour. |
|
I like the set screw idea - why not mount the set screw horizontally, so it impacts the sight post at a 90 degree perpendicular angle? A small allen head set screw, say 4-40 should do it, and it'd be an easy fix. It wouldn't impact the detent notches on the sight post, just the post itself, but who gives a rats ass? I also think the AK post idea has great merit, perhaps simpler and more elegant solution. Does it have the adjustability required however?
|
|
|
|
Sorry if this is mostly my fault. There seems to be plenty of material on the rapid prototype. I think the best solution would be to move the front sight post forward a little bit and either not use the detent or use a different kind of detent like a set screw or something else.
Dustin |
|
As Danny Coonan used to say to me when something got F'ed up,
"Welcome to the world of mana-factur-in" |
|
Quoted:
Sorry if this is mostly my fault. There seems to be plenty of material on the rapid prototype. I think the best solution would be to move the front sight post forward a little bit and either not use the detent or use a different kind of detent like a set screw or something else. Dustin Dustin, please don't blame yourself for this. We are lucky you donated your time and skill for this project. I think this is one of those small oversights that many of us involved did not catch, so pointing blame won't help. Oh, shrinkage on the part didn't help us either. I only hope you understand how much all of us appreciate your help with this project. If there is one thing that I've learned in this whole process it is that we should all appreciate what a company goes through trying to bring a product to market. How many times in history has such a problem occurred. Who's to say that the original FSB even had a detent, maybe it had something more like the AK. |
|
I very much like the idea of the AK type site and sincerely appreciate the work and effort that you and others are putting into this project.
|
|
It seems to me that the easiest way to solve it might be to move the sight pin forward a bit and tap the hole all the way through. A small set screw up from the bottom would lock the sight pin shank and wouldn't be visable. I think that is what Andouille said, and it's how I'd finish mine.
It's unfortunate that this happened but it's common in design & development. Most of the initial run usually goes in the trash. Thanks for your work with the castings JT, I'm sorry that my present situation has prevented me from being more involved |
|
Quoted:
I very much like the idea of the AK type site and sincerely appreciate the work and effort that you and others are putting into this project. A big +1 on this. As an aside Jerrell - good to 'see' you here. Please give our best to Susan. |
|
|
I'm wondering if a different detent from a LPK would be a smaller diameter? Don't have my LPK bin in front of me, but it's a thought.
|
|
Quoted:
I'm wondering if a different detent from a LPK would be a smaller diameter? Don't have my LPK bin in front of me, but it's a thought. smallest one with a lip is the a1 rear sight wheel detent iirc. |
|
Is it smaller than the front sight detent? I mean, they don't need much extra material from the look of that last pic.
|
|
I love how this forum comes together for the collective good of the group. It sure sounds like we have several great ideas here. Well, one way or another several people wanted a raw casting to do their own machining, so it will be interesting to see what some people end up doing with their stuff in the end. I for one don't have those skills, so I'm going to rely on someone else to help me with my sight when I get it ready to be machined and mounted.
|
|
Quoted:
I don't know if this will help but, I do have a picture of the original. The detent is in the front and the material is very thin, the detent may even be smaller. http://i28.photobucket.com/albums/c248/GKCF/Internet%20photos/arfsp4.jpg Well, that picture confirms it. Thanks 57Octane |
|
Quoted:
Sorry if this is mostly my fault. There seems to be plenty of material on the rapid prototype. I think the best solution would be to move the front sight post forward a little bit and either not use the detent or use a different kind of detent like a set screw or something else. Dustin No finger pointing,,and if anyone dares to,you can rest assured the rest of us will beat them down. You did one HELLAVA job with this project.Hell,I was NEVER even "in" for one,but after seeing this all come together,,,how could I not,even my Buddy Nick is down for one!!! |
|
Looks to me like the rear sight detent scheme is the winning hand.
|
|
Does anyone know what happened to all the surplus M16A1 small parts that JSE Surplus recently had on their website. I seem to remember them having New Old Stock (NOS) bags of A1 rear sight detents. Now I can't find them. Surely they didn't sell off all that stuff. They had like sixty something of the M16A1 pistol grips for like $8 ea.
|
|
Im gonna try and get my head wrapped around this. After getting my h/g's and 601 lower in yesterday, I was thining about checking up on this thing.
Looks like my SBR stamp wont be a hold up on this build. If you guys want some A1 posts and detent to work Ill supply them I personally like that original sight post. |
|
You could also drill the hole for the detent and spring at a slight angle, allowing for more material front and aft of the assembly. I don't see anything wrong with the original FSB configuration either.
|
|
Another angle would to be blind cross drill a 1/6 dia. hole into the sight post threads and inset a piece of 1/6 nylon rod. And make it into a self locking thread. self locking screw
It would stay put, but still turn easy enough to adjust with a front sight tool, I've had several USGI surplus no drain hole butt stock screws that was made with a white nylon locking insert to keep the screw from loosening up. You can get 1/6 nylon rod from McMaster Carr. 1/6 nylon rod Would not need to worry about a detent pin. Just a thought. |
|
My choice would be
Mod molds if pour hasn't happened Smaller detent loctite 4-40 drainhole setscrew. pezboytate, aprox 200 of us have OK'd the design by our excitement and pushing this forward. Even more have seen the thread. You have no part of any blame for what we all missed. Shrinkage was brought up early on. We were all worried about the cosmetics being perfect. It is normal during R&D to find issues due to castings, foundry techniques, alloy, machining, fixturing, and sometimes finishing, that all require minor changes or complete redesigns. This may not be the last issue before we get these in our hands. I want to thank everyone who has been involved in this project with their time, suggestions, work, and enthusiasm. |
|
use a wire, as a tension or torsion spring to fit in the detent slot on the front sight,
maybe have it coiled or inserted in a base (think extractor for a grease gun/1911 type) that is inserted from the top, short enough to extend just slightly above the base of the sight at it's full adjustment height, and strong enough to spring against the front sight and still be able to be pushed out of the way to adjust, just a thought |
|
Sign up for the ARFCOM weekly newsletter and be entered to win a free ARFCOM membership. One new winner* is announced every week!
You will receive an email every Friday morning featuring the latest chatter from the hottest topics, breaking news surrounding legislation, as well as exclusive deals only available to ARFCOM email subscribers.
AR15.COM is the world's largest firearm community and is a gathering place for firearm enthusiasts of all types.
From hunters and military members, to competition shooters and general firearm enthusiasts, we welcome anyone who values and respects the way of the firearm.
Subscribe to our monthly Newsletter to receive firearm news, product discounts from your favorite Industry Partners, and more.
Copyright © 1996-2024 AR15.COM LLC. All Rights Reserved.
Any use of this content without express written consent is prohibited.
AR15.Com reserves the right to overwrite or replace any affiliate, commercial, or monetizable links, posted by users, with our own.