Need support and a little advice

[Turtle]

  I am ready to attach the barrel lugs to my 42"X 50cal rice southern classic barrel. I have read all the great threads on this but am nervous. I'm thinking of soldering the center lug with SWIF as I do on my fowlers and using a shallow dovetail on the rest. Or should I just solder the front also? I plan the use 3 lugs. Should I prep the interior of the barrel any way before soldering? Do I need to support the barrel to prevent bending? Guess I have "Gotten old and scary".
                                              Thanks Turtle

[frogwalking]

I am building a small hunting rifle for my grand daughter.  It's 40 caliber barrel is smaller than the Southern classic, so I did as you are thinking.  I installed front and rear tennons via a .50 deep dovetail, and soldered the center one.  This has the additional advantage of making the keys or pins line up better than if they were all dovetailed.  I did not take any special precautions for the bore.  As the barrel was cooling, however, I did run an oiled patch through, and again after it was cool to the touch.  Better safe than sorry.  I now always provide the following disclaimer: " I am a hobby builder and not a professional."

[flinchrocket]

I'm with frog, solder the center one( I use 4 on 42 in and up barrels). .040 deep dovetails is plenty good.
Make your own from .040 brass, easier to drill and slot. Put your pins all in line along with your ramrod
pipe pins( may have to fudge a little). A line connecting all these pins is a good location for a moulding
or incised line on the upper forearm ( hides the pins somewhat).

[David Rase]

You can easily get away with a dovetail depth of .030" for barrel lugs.  Should be no worries.
David

[Dennis Glazener]

I agree with David but if you don't feel right working with that depth I would still file down a few thousandsth's then solder the lug in the filed out area. This will help if you have a thin web between the barrel and rr hole. It will give you more of the lug to put your cross pin through. Hope this makes sense.
Dennis

[WKevinD]

Solder the center one! I just found out the hard way on a southern classic. I made my underlug dovetails as usual, mark the layout, score with the hacksaw every 3/32", clear the cuts with a cold chisel and file to finish. All went well till I pulled the breech plug to drill for the vent liner and pushed a patch thru to clear the metal shavings...I had dented the barrel at the center underlug inlet when I had chiseled my cuts not badly but enough that it can be felt with a tight patch and seen with good light on the inside. I am soldering that lug on the replacement barrel.
By the way the vent liner was the last thing I was doing before final finishing and in spite of the fact that I got another SC from Jason I had to refit the barrel. Lesson learned....solder that center one on thin barrels! 

[Hungry Horse]

 You might be surprised at how shallow some original barrel lugs were cut into old barrel. I am currently working on a Lehigh longrifle, that has barrel lugs made from the same brass material the ramrod pipes are made of. They are the shallowest dovetails I've ever seen. Now, granted, they did pull loose over time. But, I believe it is more because the pin holes weren't slotted, and the forearm shrunk, than the delicate nature of the original lugs.

   Hungry Horse

[D. Taylor Sapergia]

I use a similar system for cutting dovetails.  And I like them to be shallow.  I use a hacksaw to make cuts across the barrel, but they are as close together as I can make them.  The webs between the cuts are very very thin, and a flat die sinker's chisel removes them fast and easily without damaging the bore.  I do not use a cold chisel to upset the dovetails unless I'm working with a very heavy barrel.

[jerrywh]

 Nobody asked what the diameter  the barrel was. To answer your other question, you cannot hurt a barrel in anyway by soft soldering either inside or outside As long as you stop heating when the solder melts and don't quench the barrel. even quenching a barrel at 600°F will not warp it.  It has to be above 800°f before it will permanently warp. Even if you cut .040 deep dovetails I don't see any danger.  By the time that bullet gets 27" up the bore there isn't much pressure providing there is no obstruction.

[Long Ears]

Hey frogwalking, I sure hope you missed a zero in that decimal quotation. Bob

[bgf]

I make most lugs out of ~0.030 steel (folded) and solder them into a shallow dovetail with silver bearing solder (430dF flow).  This eliminates deep dovetail and is very strong.  Really about as fast to solder 3 as one!

On the thin part, solder only will be fine, you can file the base of the lug thin and inlet a relief into the stock.

[frogwalking]

Yes Bob.  Thanks.  I meant 50 thousandths.  a half inch deep dovetail belongs on a pine ammo box.

[Long John]

Friend,

You might want to take a lesson from the original guns.  You don't need a real deep dovetail cut.  What you need is sufficient over-hang at each end of the dovetail cut to adequately engage and capture the lug.  In the old days this was commonly achieved by lifting-up the metal at each end of the dovetail with a cold chisel.  This overcomes the short-coming of most three-corner files - rounded corners. 

I cut my dovetails at most 0.030" deep, with a three-corner file, and about 0.060" to 0.075" short of long enough to allow the lug to slide into the cut.  Then I take a cold chisel with a nice sharp 60 degree cutting edge and I upset the steel at each end of the dovetail cut, a few thousandths at a time until I have pealed up enough metal to allow the lug to slide into the mortise.  This gives me two tabs of steel at each end of the mortise that are about 0.060 long at each end of the mortise.  With a nice, sharp 60 degree ends on the lug and nice sharp 60 degree slots at each end of the dovetail mortise you will have plenty of engagement and all the strength you could need.   You then slide the lug into the mortise and swedge the tabs down for a tight assembly.  If you feel really anal about it you can flux the installed lug and solder it with tin/silver low temperature solder to make sure it doesn't work loose over time; although I've never seen a lug do that.

Note that I am a hobby gun-maker, too, and certainly no professional.  I reserve the right to be wrong and openly spread it around.

Best Regards,

John Cholin

[jerrywh]

 Keep in mind that there really isn't very much strain against the bottom barrel lugs. There really isn't anything pulling against them. Some people put too much emphasis on them.   

[Acer Saccharum]

I agree with Jerry on lug strength. You just don't need much.

All the lugs are doing is holding the forestock to the barrel. They keep the wood attached to the barrel so when you pull the ramrod in and out, you don't pull the forestock away from the barrel. That's it. There is never a big stress demand on the lugs unless you use your gun like a club in a bar room brawl.

[JCKelly]

As far as preventing warping goes, I would suggest heating the barrel the same all about the circumference, where your lug is.

If one side of the barrel reaches 500F while the opposite side us 100F it will surely bend. Permanently.

It will be concave to the hotter side.       

[Turtle]

 Thanks so much guys. All done, I soldered the middle one. I also came up with a better way to get a uniform proper  depth of the dovetail, which always was a problem for me. I fastened a scribe to a 3" ruler so that it protruded .035". Then after filing the dovetail close, I put the ruler lengthwise with the scribe point in the dovetail. By moving it fore and aft, it made scratches on the high areas. Worked slick! I then used a Track of the wolf dovetail chisel and 3 cornered file to get it perfect.
                                   Thanks again for everything! Rich