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jimbullet

front sight loose on dovetail - help

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I bought a fiber optic front sight Brazos sight for my STI. Since it was oversized, I started to file it at the bottom and on one of the side (I now know I shouldnt be filing on the side - read somewhere that there was a risk of changing the dimensions, and found this out after I have already done it!)

So the end result was I filed too much and the sight appears to not be touching the entire dovetail groove as I may have changed the angle. Its touching the corner tip but could see some gaps.

Though it appears to be holding but a light tap could easily drift it off alignment and Im worried that it may not hold when firing.

My question is, so are the sights now stuffed and I need to get a new one since I may have taken too much material and changed the angles or can it still be saved by some gunsmithing work?

I dont want to change dimensions on the STI slide as I may want to change the sights again in the future.

Any help would be appreciated.

Edited by jimbullet

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When I encountered loose dovetail sights, I had some .0005" and .001" brass shim stock strips that I'd cut a little rectangle out of that (more or less) duplicated the bottom of the sight dovetail flat. More often than not, one thickness or the other would tighten up the fit sufficient to hold the sight in place. Every now and again, I'd run into one so screwed up I'd need a stack of shims until I could obtain another sight. :goof:

I agree with toolguy in that 620 is the preferred Loc-tite for a high temperature, slip fit application as it will fill pretty thick gaps... although it may not cure fully in areas exposed to air. C

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Thanks all for the help. I'll give the lock tite a go.

Brass shims...I will look into them too...I presume you placed locktite between the sight and the brass shim and also between the brass and the slide....

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If you don't have brass shim stock handy, just cut up an aluminum pop can. Works great for shims.

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Or green 620 Loctite.

+1. Green stuff fills gaps and holds well. Small bottle is 10 or 15 bucks.

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In addition to the 620 loctite warren recommends, I suggest taking a center punch and raising a small dimple or two on the bottom of the sight blade. This has worked for me to tighten up loose fit, then add some glue to hold in place after final adjustment.

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Send it back to me I will replace it at no charge - just don't mess up the replacement.

That would be fantastic! Thanks for the offer but I'm not quite sure if you would be able to as I am based in New Zealand, though exported the sight from the US.

I'd be able to send it out from here but, dont know if it would get through the US border.

Edited by jimbullet

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Sorry, I guess that won't work - we don't export. I would use a prick punch to raise a couple of dimples in the slide and the bottom of the sight and then use locktite 620 as suggested above.

Edited by Brazos Custom

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I have drilled through the sight and slide to install a cut down .0625" roll pin to fix poorly fitted sights from STI.

Use the shim and some Loctite 620 in the first instance, if it moves I would prick punch the base of the sight and re-shim/Loctite again... then drill the sight and do the roll pin fix.

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That is just the way Bob is! He gives all gunsmiths a good name.

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I have used a prick punch to dimple the bottom of the sight dovetail. Just make sure you have the wings of the dovetail supported on the vice jaws not clamped on the sight blade. All you need is a few dimples to tighten it up. And always fit the sights, not the slide's dovetail cut. If there is any doubt on it staying, add the loc-tite.

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Here is a method of sight tightening that has worked for me:

Sighttightening.jpgSighttightening1.jpg

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Thanks for all the tips, I will give this a try and will put loctite on it too.

Guncat, Im not too sure how I could "bend" the ends of the dovetail as suggested though, unless I remove more material on the sides of the sights' dovetail, which is worry some...

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On 5/31/2013 at 9:12 AM, wide45 said:

If you don't have brass shim stock handy, just cut up an aluminum pop can. Works great for shims.

+1 saved my butt, beer cans work just as well 🙂

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I have used a piece of fine grit sandpaper during a match when the sight came loose.  Held perfect, still does.  

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