How to taper the holes on a front sight base.

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[ARCHIVED THREAD] - How to taper the holes on a front sight base.

Posted: 10/6/2004 9:34:28 AM EDT

So if I'm up to drilling the holes in my new FSB, how do I then taper the holes? The pins are tapered and I was wondering what you would use? Thanks

Posted: 10/6/2004 9:58:17 AM EDT

[#1]

You'll need a "Tapered reamer"

Find out the config. of the hole (Length, major dia/minor dia)
from a gunsmith: I doubt they use a standard reamer (#2, #1, etc.)

Machinery's handbook should help if it's a standard hole.

(I'm a machinist, not a gunsmith....)

Good Luck!

Posted: 10/6/2004 10:04:37 AM EDT

[#2]

the truth is you don't need tapered holes.
you just need a friction/force fit. maybe a little locktite if your anal.

Posted: 10/6/2004 10:27:14 AM EDT

[#3]

I can't look now but there are bits that are sold for this job... check Brownells...?

Posted: 10/6/2004 10:47:46 AM EDT

[#4]

I can't seem to let go... I looked up the info you need....

www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=5613

In case the link don't work... Product ID: 080-726-004

Pins Number: 080-725-001

Posted: 10/6/2004 10:54:42 AM EDT

[#5]

If you want your FSB to hold zero, you'll make sure the taper pins are done correctly. The proper size taper reamer is 2/0. The holes on your FSB have to match EXACTLY with the original holes in your barrel, or else you may end up with a canted FSB, which you may or may not be able to adjust for with your rear sight windage adjust. Good luck.

Edited to add: Loctite won't work.

Try this for the taper reamer:Taper Reamer - same as Quarterbore's link, sorry.

Posted: 10/6/2004 11:09:10 AM EDT

[#6]

Quoted:
If you want your FSB to hold zero, you'll make sure the taper pins are done correctly. The proper size taper reamer is 2/0. The holes on your FSB have to match EXACTLY with the original holes in your barrel, or else you may end up with a canted FSB, which you may or may not be able to adjust for with your rear sight windage adjust. Good luck.

Edited to add: Loctite won't work.

Try this for the taper reamer:Taper Reamer - same as Quarterbore's link, sorry.

Hey... Nice to see I am not the only Adult that goes through the Brownells Catalog like a small child would a toy catalog.... I must have 50-flags in mine with items I intend to buy and this happens to be one of them....

Posted: 10/6/2004 11:17:31 AM EDT

[#7]

Quoted:
Quoted:
If you want your FSB to hold zero, you'll make sure the taper pins are done correctly. The proper size taper reamer is 2/0. The holes on your FSB have to match EXACTLY with the original holes in your barrel, or else you may end up with a canted FSB, which you may or may not be able to adjust for with your rear sight windage adjust. Good luck.

Edited to add: Loctite won't work.

Try this for the taper reamer:Taper Reamer - same as Quarterbore's link, sorry.

Hey... Nice to see I am not the only Adult that goes through the Brownells Catalog like a small child would a toy catalog.... I must have 50-flags in mine with items I intend to buy and this happens to be one of them....

Mine ends up looking like a worn out paperback novel.

Posted: 10/6/2004 12:13:26 PM EDT

[#8]

I typed up the process to do this and added it to my website... Note, the only time I had to do this was a couple years ago when I removed a pre-ban gas block from a upper and replaced it with a post-ban version. I welcome updates or corrections to the steps I outlined but this is the general process to do one of these swaps...

quarterbore.com/forums/viewtopic.php?t=131

Note: I swapped the parts as the pre-ban gas block was a flip-up GG&G unit and I wanted to use the barrel with an A2 Front Sight base and use the flip-up for a M4 project... I figures someone would ask why I would bother...

Posted: 10/6/2004 12:20:50 PM EDT

[#9]

Quoted:
I typed up the process to do this and added it to my website... Note, the only time I had to do this was a couple years ago when I removed a pre-ban gas block from a upper and replaced it with a post-ban version. I welcome updates or corrections to the steps I outlined but this is the general process to do one of these swaps...

www.quarterbore.com/forum/viewtopic.php?p=208#208

Note: I swapped the parts as the pre-ban gas block was a flip-up GG&G unit and I wanted to use the barrel with an A2 Front Sight base and use the flip-up for a M4 project... I figures someone would ask why I would bother...

I've got a jig in production right now to do this. I hope to install a GG&G on my SAM-R clone, but I'd really like to get my hands on one of those KAC front fiip sight bases.

Posted: 10/6/2004 3:50:43 PM EDT

[#10]

Thanks guys, I'm also thinking about putting a 4 rail gas block on one of my uppers. I don't like the idea of just 2 allen screws holding it on. I don't want a solid thwack on some random object throwing off my sights.

Posted: 10/6/2004 4:51:04 PM EDT

[#11]

I've been using the setscrew fsb's forever, it's perfect for setting your windage zero exactly without messing around with the barrel slot or pin. I can always get a perfect zero centered windage adjustment using these sight bases. When set correctly, I then loctite the allen screws one at a time so as not to disrupt zero, then use loctite "green" wicking compound to seep into the barrel bands. This procedure will hold as well as the pain in the #%$ pins will. I know, because when trying to remove the fsb at a later date, it is just about impossible without using a torch and a deadblow hammer.

Posted: 10/6/2004 5:32:36 PM EDT

[#12]

Quoted:
I've been using the setscrew fsb's forever, it's perfect for setting your windage zero exactly without messing around with the barrel slot or pin. I can always get a perfect zero centered windage adjustment using these sight bases. When set correctly, I then loctite the allen screws one at a time so as not to disrupt zero, then use loctite "green" wicking compound to seep into the barrel bands. This procedure will hold as well as the pain in the #%$ pins will. I know, because when trying to remove the fsb at a later date, it is just about impossible without using a torch and a deadblow hammer.

I had thought about leaving my fsb alone and using a liberal ammount of red locktite as a fix. The only thing is I seem to constantly modify my AR and a pin would be easily removable yet very secure.

Posted: 10/7/2004 1:56:48 PM EDT

[#13]

1/4Bore Your description is pretty good. I'm not sure what to make of this "The place to start is by installing the new gas block to the barrel and look at the alignment of the holes through the front sight base. With luck, you will be able to see the holes in the barrel through the holes in the new gas block."

I take it that is if the new FSB/gas block is predrilled for taper pins? What are you trying to see through?

I wish some one would do one of these and take pictures along the process. I forget who it was posted a PDF with pic's on how to remove an armalite muzzle brake. Too bad there wasn't one like it on how to install a new FSB.

Mongo Is your jig going to be available for sale to board members?

Daubs

Posted: 10/7/2004 2:17:47 PM EDT

[#14]

Quoted:
Mongo Is your jig going to be available for sale to board members?

Daubs

I only plan on building one jig, for my own personal use and maybe for people who live close to me. I was drawing up some of the parts on CAD today and I hope to start cutting the parts soon and do final assembly soon after. It is still a living build and parts change as I draw them both on paper and in my head. It'll be a little while before I have a working prototype. All this is done in my spare time at work, lunch break and other dead time.

Posted: 10/7/2004 4:53:02 PM EDT

[#15]

Quoted:
1/4Bore Your description is pretty good. I'm not sure what to make of this "The place to start is by installing the new gas block to the barrel and look at the alignment of the holes through the front sight base. With luck, you will be able to see the holes in the barrel through the holes in the new gas block."

I take it that is if the new FSB/gas block is predrilled for taper pins? What are you trying to see through?

Actually, when I did mine (about 2-years ago I will add) I added a used FSB so it was drilled... New ones would be undrilled and I may well do one and take some pics if I get the time as I really am not sure how I would do it yet without the original holes... Well, not sure enough to put it in words

Posted: 10/8/2004 5:36:29 AM EDT

[#16]

Thx for the reply's.

YHM has a flip up gas block/front sight that they are going ot be producing with a bayonet lug, I'd like to use the taper pins of my curent no-ban FSB to install though.

[ARCHIVED THREAD] - How to taper the holes on a front sight base.

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