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Double Rifles, Single Shots & Combinations >> Building Double Rifles & Gunsmithing

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meharold
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Why solder?
      #250291 - 11/07/14 10:47 AM

I plan to eventually build a .450 N.E. on my Zabala 10 Ga. To gain experience I am making a 30-40 Krag rifle barrel with a new monoblock for my Savage 220 single shot. The process seems pretty straightforward. One of the questions I have right now is: Why solder the barrels to the monoblock as shown in Mr. Browns book? Why not just thread them like a bolt gun?

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DarylS
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Re: Why solder? [Re: meharold]
      #250293 - 11/07/14 10:56 AM

Some do thread - others solder - soldering would be easier I'd think. I've always been better at soldering than threading. Get the parts 1 mil apart and solder - much easier.
Ron Vella went heat shrink as well as spot welding - more than one way to accomplish the same thing - attaching barrels to a monoblock.

Note, I've never done this - my opinion based on meager experience playing with guns'n stuff.

--------------------
Daryl


"a gun without hammers is like a Spaniel without ears" King George V


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meharold
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Re: Why solder? [Re: DarylS]
      #250333 - 12/07/14 12:19 PM

Thank you. I'm a toolmaker, so I'm much more comfortable threading than soldering.

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Birdhunter50
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Re: Why solder? [Re: meharold]
      #250731 - 20/07/14 04:06 AM

A better question is why thread them? Brownells Hi Force Solder will hold them just fine, as long as you have them closely fitted and pre tinned. The one time I threaded barrel stubs it was a real nightmare. You have to be sure that your monoblock ends are perfectly perpendicular to the bores and the the shoulders on the barrels are the same way. Then the barrels must be threaded perfectly and the monoblock the same. Lastly you have to put them in very tightly and get the surfaces down flush with each other. I found it very hard to thread and solder the stubs in because everything has to be really hot to allow you to get them tightly down where they belong. It is much easier to get them tightly together by soldering. Threading weakens the monoblock walls substancially and I don't see that it does that much good above the soldering. Bob

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Waidmannsheil
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Re: Why solder? [Re: Birdhunter50]
      #250741 - 20/07/14 09:40 AM

I disagree wit the idea that threads weaken the monoblock, especially if the wall thickness is reasonable. Most bolt action rifles have their barrel threaded into the receiver, often with small rings and they are hardly weak. You can always use a finer thread as the threads won't be case hardened and they are better against vibration resistance anyway. (Most automotive thread are fine threads for that reason). As far as your difficulties with cutting threads and getting mounting faces and shoulders square, it all depends on the quality of your machinery and your level of skill. We cut a lot of threads at work, both external and internal with no problems at all, but then we are doing it a lot and have been doing them for a long time and we have good machinery and very good tooling which does make a difference.

Waidmannsheil.

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TennHillBilly
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Re: Why solder? [Re: Waidmannsheil]
      #250844 - 22/07/14 02:21 AM

I've watched a number of the factory videos on You Tube showing assembly of a double, e.g., Heym. Looks like they use what I'll call a 'shoe lump' system and solder the barrels directly onto it. In other words, the bottom part of a 'monoblock'. Just watching the process suggests to me they don't use an especially high heat brazing material. Some of the heavier silver brazing material I have requires red hot heat to flow. If my observations are correct, seems threading is nice but not necessary. Threading would, I think, making replacing a barrel easier. Been kind of wrestling with this for my own project.

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dpcd67
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Re: Why solder? [Re: TennHillBilly]
      #256230 - 03/11/14 06:08 AM

If your soldering is perfect; then you don't need threads; right on the Heym; the shoe lumps are hard soldered (probably silver brazed) directly to the barrels. I prefer to thread and have used tin solder sometimes; usually not. I do not use hard (braze type) solder; it takes too much heat and is hard to remove if you ever need to. I have used Brownells hard solder on the regulation wedge but that stuff is hard to use.

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Birdhunter50
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Re: Why solder? [Re: Waidmannsheil]
      #256246 - 04/11/14 12:40 AM

Waidmannsheil,
I understand your idea about doing the threading precisely but to compare the threaded barrels on bolt actions and the threads cut on the inside of mono blocks is like comparing apples to oranges. The bolt guns have very thick walls and they are screwed into thick walled actions. With a monoblock you don't have the luxury of all that barrel thickness, no matter how fine a thread you cut inside a monoblock, you will substancially weaken the walls of the monoblock up to or exceeding 50 percent. It can't be helped because you are cutting away half of the wall thickness of the monoblock.
By using Hi Force and getting all the mating surfaces thoroughly tinned before trying to put them together, you will get almost 100 percent of the holding strength of the solder, which is listed at 28,000 PSI. If we round off the circumference of a typical barrel stub as being 3 inches around, which is pretty close in most cases, then take that times the length or the stubs, another three inches, that squares out at 9 square inches of mating surfaces per side.
When you multipy that out you will come up with 252,000 pounds of holding strength PER SIDE. The British and the Italians have been monoblocking barrels for many years and using softer solders than this to do it. This is not theory, I have done lots of guns this way and none of them have come apart yet. Bob


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DarylS
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Re: Why solder? [Re: Birdhunter50]
      #256252 - 04/11/14 03:16 AM

Solder as I understand it.

There is what we call plain "Silver Soldering", what people in other parts of the world call high temp silver soldering, or silver brazing - red heat or a bit higher - from 75,000 to 90,000PSI shear on a 1 mil bond, or so my Dad taught me.

There are also different makes of silver solders in varying degrees of strength and fluidity. Some, as used for soldering on the carbide teeth on lumber mill circular saws, need more head but are the strongest of silver solders - usually a square rod about 10" long. The silver wire sold by Praxair, here in town, is really nice to use as it flows beautifully into every fluxed area.

Long after we became fairly proficient at Silver Soldering, a low temp silver solder became available and thus we called it low temp silver solder - it is usually around 5% silver content & has no lead in it's matrix -400 to 500 or so degrees - It's 1 mil bond is stronger than lead solder.

There is lead soldering which usually is a lead/tin amalgamation, 50/50 to 70/30 - 450 to 550 degrees?

Seems to me that High Force or Force 44 are low temp silver solders, with 5% silver content?

--------------------
Daryl


"a gun without hammers is like a Spaniel without ears" King George V


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Waidmannsheil
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Re: Why solder? [Re: DarylS]
      #256256 - 04/11/14 08:46 AM

Birdhunter50,
I should point out here that I am not trying to promote threading over soldering, just that it is another method of fastening. As to the apples and oranges comparison, not sure about that one as both are methods of fastening two pieces of steel together, just different ways of achieving the same goal.
It is true that some bolt action rifles have greater wall thickness such as Mausers but not all do. My 1903 and 1910 Mannlichers have a wall thickness of 2.5mm (0.1 inch) and guns such as those made by Howa are similar. Most mono-blocks would have at least that much wall thickness especially with double rifles as the barrel stub is smaller in diameter as compared to a shotgun.
Bolt action rifles also have a significantly shorter thread length, often no longer that 3/4 inch and Mausers are only 0.5 inch. Commercial rifles often have a fairly poor thread fit as well. A mono-block however can be between 2 and 3 inches long and with a well fitted fine thread will provide massive strength and still allow for minimal wall thickness especially with todays modern steel.
This is particularly true if the male thread is cut with a Spiralock type thread where the torque loading is spread evenly along the length of the thread, as opposed to the normal thread form where the load is only over the first few threads.
I think it was P.O.Ackley who took an Arisaka rifle and kept turning a small amount off the thread diameter and than firing it with live ammunition. He kept doing this until there was almost no thread left and provided that the ammo was free from lubricant, the gun stayed together without spitting the barrel out.
As I said, I am not trying to say that soldering is no good or old fashioned, just that threading is a viable alternative and it can be done without the need for a muffle furnace or similar devices.

Waidmannsheil.

--------------------
There is nothing wrong with vegetarian food, so long as there is meat with it.


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AkMike
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Re: Why solder? [Re: Waidmannsheil]
      #256267 - 04/11/14 03:33 PM

On a different note, That 10 ga is too big of an action for the 450 NE. IF it's a larger size than a 12 ga action. I have a 12 ga JP Sauer conversion that still feels a bit clunky and barrel heavy compared to others of mine.

Personally I'd reconsider that aspect of it.

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"When you see that in order to produce, you need to obtain permission from men who produce nothing; when you see that money is flowing to those who deal not in goods, but in favors; you may know that your society is doomed." Ayn Rand


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dpcd67
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Re: Why solder? [Re: AkMike]
      #256281 - 05/11/14 06:48 AM

Brownells force 44 is tin with 5% silver and has a lower strength than silver brazing. I have done them both ways, solder, with force 44, and threading; I always feel better with threads. I don't think that threading the monoblock weakens it enough to matter; all the ones I have threaded have not noticed.
Make sure you don't confuse hoop (radial) strength, with axial, linear forces. With our modern chrome moly barrels, radial strength is of little concern. And with the relatively low pressures in double rifle calibers, linear forces are easy to deal with as well. All of which is why it is possible, safely, to make double rifles on shotgun frames.


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DarylS
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Re: Why solder? [Re: dpcd67]
      #256287 - 05/11/14 10:52 AM

Seems to me, I've read that low temp silver solders, like Force 44 & the rest, with 5% tin, have up to 30,000psi shear strength in a 1 mil bond. Also, that 50/50 or 70/30 lead solders, commonly used for soldering barrels and ribs for over a hundred years, has a strength in the 15,000 to 25,000 pound range - with a 1 mil bond - which is which or if this is accurate, I do not know. I am only regurgitating what I read - somewhere.

Few joints, as my Dad often told me however, are one mil - which only leaves .0005" clearance on clean metal to metal, which could not quite leave enough room for tinning - would it? Now, with the proper heat and flux, high temp silver would work perfectly, given perfect application.

I can easily see where threads would solve some headaches, but perhaps creat others?

That said, I've never heard of a BPE or Nitro Express set of barrels loosening in their monoblock while only being soldered with lead based solder. Ribs - yes - with poor care and abuse, but monoblocks - never. Maybe I've lead a sheltered life form such occurances?

--------------------
Daryl


"a gun without hammers is like a Spaniel without ears" King George V


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Birdhunter50
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Re: Why solder? [Re: DarylS]
      #256301 - 06/11/14 01:25 AM

Daryl,
Close fitting is very important but on joints with the areas of monoblocked barrels you will not get a one mill fit, nore is that necessary. I try to get 3 to 5 thou. close fit and that is plenty good enough. More important is that you get them properly soldered with as close to 100% contact as you can get. This comes from cleanliness of the metal surfaces, thoroughly tinning the parts, washing off all the acid flux, refluxing with resin flux, and bumping down the barrels to get them fitted as tightly as possible. Bumping down consists of very slightly undercutting the shoulders on the barrel stubs, and the front surfaces of the monoblock. When these two surfaces are driven down with a brass hammer, the undercut surfaces slightly mash together to make a virtually invisable joint.

This is how the British used to do their shotgun monoblocking. A hardwood block is set on the floor with the barreled monoblock rested on it, then after reheating, the barrels are "Bumped Down", their words, not mine. This is done with a fairly heavy brass or copper hammer. A steel hammer can be used if you put a heavy piece of maple or oak wood over the muzzles, but if it breaks during the process, you could easily damage a barrel or two. You can't do this procedure with threaded barrels.

On the first gun I built, I didn't have a lathe and I hired a guy to machine the barrel stubs and thread both the monoblock and the barrels. I told him how I wanted it set up so the each barrel would be properly lined up with the monoblock. Long story short, he didn't listen to me and screwed up the threading something horrible. The barrels not only spread as the went towards the muzzles, but they would not seat down correctly against the monoblock. I was finally able to get it finished but not without a bunch of trouble. I have since bought my lathes and have not had a repeat of this mess.

Whenever I can, I bore out the monoblock to completely bore out the old rim cuts left over from the shotgun chambers. This leaves very little wall thickness on the front of the monoblock but that really doesn't matter, the barrels are fitted up against the standing breech face so that they don't impart any recoil pressure against the joints anyway. This method gives a very tight joint visable from the breech end and none of those silly rings to fit up and solder in.

This fit up will not work on some lighter weight gun frames because the barrels reduce too quickly in diameter to allow for a decent length monoblock. Don't try this with lightweight bird guns, you want a standard weight donor gun to start with. Because of the amount of the areas on the barrel stub joints, a very thin monoblock front wall can be used, this also leaves the barrel walls thicker in the chamber areas which is very important. None of this will work with threaded barrels. Bob


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Shotgunlover
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Re: Why solder? [Re: Birdhunter50]
      #256302 - 06/11/14 03:21 AM

Birdhuner, thanks for the clear description of the process.

Maybe a note is due regarding "fretting" the monobloc as used by several French makers. It is in essence a hot version of the shrinking-on done by Ron Vella using liquid introgen. Whereas Ron shrunk the barrel, the traditional method expanded the monobloc. In fretting, the monobloc is heated to expand and accept the barrel. The cooling induces a shrink fit, and from what I read this method was copied from the manufacture of artillery pieces.

Then comes the Proof which involves firing two overpressure shells in each barrel. A gunsmith friend muses that the superior proof so liked by the French shotgun makers was employed not only for Proof purposes but also because it provided a final "set" of the barrels in the fretted monobloc.

During a visit to the Beretta factory I saw shotgun barrels waiting for joining. The machined monoblocs were put on one of the barrel stubs, as a way of storing the sets to be joined, and obviously the fit was fairly loose. Obviously there are differences between shotgun and rifle specs, but still, the apparently slack fit was surprising.

--------------------
Shotgunlover


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tinker
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Re: Why solder? [Re: Shotgunlover]
      #256303 - 06/11/14 05:07 AM

Solder and hard silver need clearance, that loose looking fit was likeky to account for the joining material.

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--Self-Appointed Colonel, DRSS--



"It IS a dangerous game, and so named for a reason, and you can't play from the keyboard. " --Some Old Texan...


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doubleriflejack
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Re: Why solder? [Re: tinker]
      #256307 - 06/11/14 07:57 AM

The "loose fit" "tightens" up a bit after tinning both interior surfaces of the monoblock, and the exterior surfaces of the barrel stubs that fit within the monoblock. W. Ellis Brown, who wrote his book on converting double shotguns to double rifles, taught us to use both half and half, more or less, threading and soldering, barrels into monoblock. Some guys use only the threading, and others use only the soldering; no threading. All work well, and have plenty of strength for purpose intended. When only soldered, the large overall surface area soldered, provides more than enough overall strength for this purpose.

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DarylS
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Re: Why solder? [Re: doubleriflejack]
      #256309 - 06/11/14 09:30 AM

Thanks Bob - well explained.

--------------------
Daryl


"a gun without hammers is like a Spaniel without ears" King George V


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dpcd67
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Re: Why solder? [Re: DarylS]
      #256393 - 08/11/14 04:06 AM

Yes, even lead soldered barrels into monoblocks is strong enough, but I still like threading. Although, I have used force 44, which is not a high temp solder, and it worked very well.
As for shrinking, I seriously doubt if that would work in this application by amateur makers. I think the hoop tension of the relatively thin monoblock walls would not hold rifle barrels in place. And I have re-barreled rifles with shrunk on barrels; they always use a cross pin to make sure.

Edited by dpcd67 (08/11/14 04:08 AM)


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TennHillBilly
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Re: Why solder? [Re: dpcd67]
      #256408 - 08/11/14 11:37 AM

This has been interesting and raises a question in my mind. After watching the Youtube factory videos which seem to all use solder/brazing, is there any manufacturer that threads doubles?

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Shotgunlover
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Re: Why solder? [Re: TennHillBilly]
      #256426 - 08/11/14 10:39 PM

The shrink-on method, cannon frette in French, is not holding the barrels by hoop tension, it also uses solder. Darne barrels are held that way with obviously good results.

TennHillBilly, the most prolific barrel experimenter was Henri Pieper, he used a variety of barrel jointing methods in his shotguns: demibloc (with dovetailed barrels), monobloc with the barrels inserted from the breech ends, monobloc with the barrels inserted from the muzzle end, threaded monobloc and others. Other than Pieper I have not come across barrels threaded into the monobloc by a commercial maker. They must exist, I am sure, but the numbers must be small. From experience I learned that gunmakers hate threading parts. Even after a four hour argument a gunmaker refused to put a split bottom plate on a boxlock shotgun because it would take an extra threaded screw hole about 4 millimeters in diameter and 10 millimeters deep. The guy would be apoplectic if asked to thread two barrels and two chamber ends 70 millimetes each!

--------------------
Shotgunlover


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dpcd67
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Re: Why solder? [Re: Shotgunlover]
      #256431 - 09/11/14 06:02 AM

I agree that gun makers avoid extra steps if they aren't required; I thread because I like the idea of a mechanical process. Although I have made one with solder only and it worked fine.
As for shrinking, AND soldering; why do both? If the fit is tight enough to shrink, where does the solder go? I do not understand doing it that way.


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