Tightening up a front sight?

[J1776]

Hello fellas.

Building my first flinter in a JP Beck style.

I have a question regarding a front sight I installed.
I had cut the dovetail in my B weight Rice barrel, but when filing (carefully) I noticed I might have gone a little to wide and had a strange hairline of gap under the base of the sight,...reallllly thin amount of gap under the base of the sight.
The front sight I'm using is a wax cast brass sight by Knob Mountain Muzzleloaders. 
I've been under the assumption that the norm on the depth of the dovetail is 1/16"...well I'm just over that in this dovetail cut, approx. 1/64" over the 1/16" depth.
Will this be a problem, and can I (or should I??) try silver soldering the front sight to take up that tiny gap area?

Also, when putting in my barrel lugs, I also went just a tad over the 1/16" depth, probably about the same as the front sight on one or two of them,...any issues here guys?

Thanks much!!

[D. Taylor Sapergia]

It's a little late for this build, but you are going a lot deeper than you need to.  Try to aim for 1/32" or .0315" deep.  then when it ends up a little deeper, it's not too deep.  Dovetails 1/16" deep in some barrels doesn't leave much steel between the dovetail and the bore.
The image below is a brass tenon in a Rice .50 cal B weight barrel (Canvasback's JP Beck).  It is made from 1/32" brass sheet, folded in half and silver soldered in the joint.  The dovetail is a perfect metal to metal fit...no solder is needed.
To fix your problem, if it were mine, I'd make a new front sight base thick enough to fill the dovetail, and the same goes for the tenons or underlugs.

[J1776]

D. Taylor,..
thank you very much for the advice.

I actually took a much closer look last evening, and I think that every one of those lugs are actually at exactly 1/16" deep and two seem to be just under 1/16" deep!
My eyes must be getting screwy!!!  Time to go see the optometrist maybe? 

However, in this particular situation, with the dept I have for the tennons, will everything be alright as-is?  No safety or durability issues?

Of course next time they're going in at 1/32", now that I know better.  It's just that before I had been told, and had read that its no big deal to put them in at 1/16"?

[J1776]

214 views and only one response?

 

[bgf]

You need to calculate how thick the barrel wall is between the base of each dovetail and the bottom of the rifling grooves -- because your barrel is swamped, it will be different for each dovetail.  I've seen 0.1" -- anyone should feel free to correct me on this -- as a safe amount of barrel wall and always try to exceed that by a good margin, but have never used anything as thin as a b-weight is at the waist, so I've never come close.  In your position, I would figure out what thickness I had for each dovetail and run it by the people here.  To little barrel wall thickness can be bad in a lot of ways, ranging from bumps or bulges in the bore to the obvious blow out (may take a few shots), so be careful.

[westerner]

You need to calculate how thick the barrel wall is between the base of each dovetail and the bottom of the rifling grooves -- because your barrel is swamped, it will be different for each dovetail.  I've seen 0.1" -- anyone should feel free to correct me on this -- as a safe amount of barrel wall and always try to exceed that by a good margin, but have never used anything as thin as a b-weight is at the waist, so I've never come close.  In your position, I would figure out what thickness I had for each dovetail and run it by the people here.  To little barrel wall thickness can be bad in a lot of ways, ranging from bumps or bulges in the bore to the obvious blow out (may take a few shots), so be careful.

Sounds good to me.

             Joe.

[Ky-Flinter]

JS,

BGF is right, figure your wall thickness at each tennon and post here for comment.

Now, for the "reallllly thin amount of gap under the base of the sight."  If the sight is otherwise tight in the dovetails and the gap is really thin I would think you could carefully peen the brass base a little to close the gap....  or just live with it.

-Ron

[Dennis Glazener]

My intention is not to scare you, just a safety check, but you need to check the wall thickness on the mid-section of that B profile barrel. When using it in .50 caliber I usually solder the mid tennon on rather than cut my normal .035" deep dovetail. Depending on where it falls in the mid-section you may have border line wall thickness between the bottom of the dovetail and the .50 caliber bore. Rice says to allow at least .100 inch wall thickness.

As to the thin gap under the tennon, I would use a flat punch and give each side of the dovetails a good downward whack, probably will close the gap and tighten the tennon at the same time.
Dennis

[Pete G.]

I have tightened a dovetail by placing a cold chisel across the flat just behind the dovetail and giving it a tap. I discovered this by leaving the rear sight sitting out on the bench and it shrank up while I was cutting the dovetail.  I have also begun to use this as a decorative touch.

[J1776]

Thanks fellas,.... much appreciated.
Now I just have to figure out what's what on the barrel thickness....

How can I do this???

[Dr. Tim-Boone]

Measure the outside diameter where you are considering a lug and then subtract the bore size + 2x the depth of the rifling grooves.

[J1776]

Measure the outside diameter where you are considering a lug and then subtract the bore size + 2x the depth of the rifling grooves.

Thanks Boone...
Much appreciated!