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Double Rifles, Single Shots & Combinations >> Building Double Rifles & Gunsmithing
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Crusader68
.224 member


Reged: 25/11/11
Posts: 41
Loc: Baton Rouge, LA
bottom lugs onto two piece monoblock
      #253757 - 20/09/14 08:29 AM

I can understand the reasoning for wanting to machine the entire monoblock in one piece, but if one was intending on the two-piece monoblock why solder rather than weld? Having worked with silver solder before, i do realize that if done correctly can result in an extremely strong joint, but why not weld the two? Is it because the stress relieving process is a pain? As Mr. Brown has clearly much more knowledge on the subject than me, I'm wondering what those specific reasons may be. Any ideas?

--------------------
Erik S.
"... mais épargnez le visage"

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TennHillBilly
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Reged: 17/05/13
Posts: 69
Loc: Tennessee Plateau
Re: bottom lugs onto two piece monoblock [Re: Crusader68]
      #253819 - 21/09/14 09:30 AM

Interesting question. I would suggest the biggest difficulty is the weld itself...that is, the fillet. I suppose if one properly 'sculpted' the lugs and block, the weld might not be be raised that much. If not, I would think filing/grinding back to right angles on the monoblock's weld would weaken the structure. I've seen some great TIG welds, maybe that process. I've watched every factory, video on Utube.....H & H, Heym, etc. I could find and I haven't seen a weld yet. Wouldn't you have to relieve the action sufficient to except the fillet? Guess you'd have to try it to find out. Anyway, one guys opinion. Remember Brown talked about trying to make a demiblock...I think....and said it was a disaster......no explanation followed. Bill

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Crusader68
.224 member


Reged: 25/11/11
Posts: 41
Loc: Baton Rouge, LA
Re: bottom lugs onto two piece monoblock [Re: TennHillBilly]
      #253850 - 21/09/14 07:26 PM

I didn't think about the need to deal with the seam post welding to fit it to the action, which is I assume why it's the standard.
I have seen almost all of the videos from the big league smiths, and Heym actually uses a shoe-lump which is pretty much a Demi-block from what I understand and it is indeed soldered on. They even use it on their .600 ne doubles so it must be more than adequate for most if not all of the rimmed chamberings.

--------------------
Erik S.
"... mais épargnez le visage"

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Shotgunlover
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Reged: 24/08/13
Posts: 45
Loc: Greece
Re: bottom lugs onto two piece monoblock [Re: Crusader68]
      #253853 - 21/09/14 10:02 PM

Is the term "solder" used interchangeably with "brazing" here?

Brazing, that is using a bronze alloy as the binding agent has a tensile strenght that approaches that of steel. Soldering has various grades, with silver solder being at the top, but still below brazing, and all the way down to very weak low temp solder used in electrical connections.

The way it was explained by an old gunmaker is that you use the strongest highest melting point binder, ie braze, for the main barrel joint, then go to a slightly less strong one for the loop and packing, and finally to a weak one for the ribs. That way there is no risk to the work done before from the use of flame, and also repairs are facilitated by not putting at risk the main bits, ie you can resolder barrels without affecting the loop, or the main barrel joint.

Brazing temperatures are in the 700 to 800 Centigrade region, which is close to the critical temp for steel, but can be controlled and not exceed it. Welding is a more drastic process in terms of local effects on steel.

The main question when it comes to barrels is why not base the design on a monobloc and avoid all the brazing-welding problems to begin with.

Edited by Shotgunlover (21/09/14 10:05 PM)

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Dumprat
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Reged: 20/02/14
Posts: 205
Loc: Vancouver island bc.
Re: bottom lugs onto two piece monoblock [Re: Shotgunlover]
      #253856 - 22/09/14 12:34 AM

You could easily weld the lumps on. But you would need to put large "V" weld prep under the area where the barrels attach. Then normalize the area before machining. This sort of work is done a lot in industrial applications where force and pressure exceed the amount proposed by a firearm. But it is also not an easy weld to do and if you are not trained it will crack or have inclusions and porosity.

And the gunsmiths I know are not welders. It is not something they are comfortable with or do with any regularity.

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Crusader68
.224 member


Reged: 25/11/11
Posts: 41
Loc: Baton Rouge, LA
Re: bottom lugs onto two piece monoblock [Re: Dumprat]
      #254213 - 29/09/14 09:34 AM

Shotgunlover: on the lugs brazing wouldn't be as big of a problem, but to get the barrels hot enough to mount sights or ribs would be too hot and likely to cause warping and ruin the barrels, which is why lower temp solder is used. From my understanding the difference between solder and braze is a temp thing with solder usually(but not always) the lower temps.

Yeah I abandoned that idea, I decided to go the longer but more rigid route for the monoblock.

--------------------
Erik S.
"... mais épargnez le visage"

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Waidmannsheil
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Reged: 19/04/13
Posts: 2443
Loc: Melbourne Australia
Re: bottom lugs onto two piece monoblock [Re: Crusader68]
      #254218 - 29/09/14 10:52 AM

I am not sure why anybody would want to make a two piece monoblock anyway as it is far more work than making it out of one piece. If you have the machining ability and the machines to make a two-piece block than you can make a one-piece block, it is a lot less work.

Waidmannsheil.

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

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