Barrel replacement services update!

[sheepherder]

This is what I imagine G.T.'s shortened barrel might look like, before silver-soldering...Four inch to three inch...

...Not that there is anyone looking for that...But it might look something like this...

[Ron Wood]

Looks like you have the process well in hand. One small suggestion is to make the turned down portion of the barrel just a hair longer than the bored out barrel band. Then it will stand a bit proud of the band when assembled and make crowning a bit easier. I have also heard that folks that perform this joining will peen the end of the barrel which makes the seam just about invisible when the crown is machined. I like the looks of what you have done. To me, a 3-inch barrel is just about perfect for a Baby.

[sheepherder]

Originally Posted by Ron Wood

Looks like you have the process well in hand.

This part is the easy part. Getting the front sight at 12:00 o'clock is the hard part.

I made the two sections equal wall thickness. Be kind of hard to peen. The stub does stick out a bit, not much, but this was just to get a feel for it...Sticking out would give the solder a place to start flow, too...

I may not shorten a carbine, however...It may be more fun to make a short fore end for an artillery...

[Olle]

Originally Posted by Rick W.

Hard silver solder is in the 1200F range, there are some folks that are a little touchy about using such on a barrel. High strength to be sure, but takes some skill that only comes with lots of experience. Everyone has to be at ease with what they are doing.

For us average garage guys, Brownells has a world of intermediate strength silver type solders. Some are offered in paste form, smallish coils, even thin ribbon(nice for ramps for some). Their two versions of HiForce 44 flow at much lower temperatures than hard silver solder and are quite strong.

I use Hi-Force 44, it's plenty strong enough for most applications. I would think that even regular plumbing solder will do in this particular case, capillary soldering makes a pretty strong bond. Personally, I would not even consider use hard silver solder. 1200F is when steel starts glowing red and I don't want to do that with a gun barrel. I'm sure it's ok in a professional shop where heating and cooling can be controlled, but that's not really the case in my basement...

[Olle]

Originally Posted by Rick W.

I agree the HiForce 44 product is ok. I also think that the Loctite 620 is ok in specific applications; both are just my own opinions. The 620 is certainly easy to use and clean up; but with some care, the other(44) is as well. Both so far have been good to me in my limited applications with high power rifle banded front sights and some simplistic Luger front sights.

I would feel entirely comfortable with this type of Loctite, Acraglas (which is commonly use to install barrel liners) or any high-strength adhesive. The only drawback is that once it's there, it's pretty much there forever. The solder is easy to reheat if you need to adjust.

Originally Posted by sheepherder

This part is the easy part. Getting the front sight at 12:00 o'clock is the hard part.

That's why I made that leveling block i showed in this thread: http://forum.lugerforum.com/showthread.php?t=30581 . I put the barrel in a receiver, then I used a level on the receiver and the block and adjusted until they were level. I had already tinned the parts so the fit was snug enough to hold the band in the right position until I got it soldered. Let me know if you want to borrow the block, it's just sitting there in a drawer anyway.

[sheepherder]

Originally Posted by Olle

That's why I made that leveling block i showed in this thread: http://forum.lugerforum.com/showthread.php?t=30581 .

I had forgotten that you had posted a barrel shortening thread already...But since all your pics are on Tinypic.com, they'll soon be lost anyway...

I hadn't considered making a little jig like that...My barrel bands have slight dimensional differences...large differences in the case of 'pencil' profile barrels (which I like)...

[John Sabato]

Sheepherder... another method for which you ARE tooled that will work as long as you use CLOSE tolerances.

Machine the barrel just as you have illustrated and measure it carefully.
Then bore out the front sight band to EXACTLY (or as close as you can) to the SAME dimension.

Mill a TINY witness mark/groove/keyway on the bottom of the barrel, that you have properly indexed to be the bottom of the barrel about the diameter of a straight pin, and very short! Length is not important here, only position.

Then mill a matching groove in the bottom back of the front sight band that you bored out.

Cut a piece of wire/straight pin/etc. to fit carefully in the groove you cut in the bottom of the barrel. This will be your index so you can't get the front side band on at an angle. Solder/superglue that little piece into the groove on the barrel. Then put the barrel in your freezer for about 20 minutes.

When the freeze is over, mount the barrel in a vise muzzle up.

Quickly heat the front sight band with a propane torch just until it starts to barely glow---pick it up (with tongs or pliers, not your fingers) and position it on the barrel using the pin/index as your guide. GET THIS RIGHT cause you only get ONE SHOT AT IT. (No pun was intended, but it works in this case )

Let it cool at room temperature, and I would wager a small sum that once cooled in place you won't shoot it loose.

This interference fit method was engineered by BMW to hold the rear wheel bearing on my motorcycle, and that bearing supports the weight of the entire motorcycle, and all the G-forces of the rear wheel---- it won't pull it off once cooled.

You could of course practice on a piece of scrap eh?

[Ron Wood]

John,
That chill barrel/heat band technique is similar to the process they use to put the iron rim on a wood spoke wheel! The index pin is a novel idea.

[ithacaartist]

The interference fit is great--it will never be shot loose, and there's no mess to clean up.

I had occasion to take such a joint apart some years ago. I was working in a local fabricating shop and, to the owner's specs, had made a short set of special dies for the press brake. The whole assembly was too short, it turned out, and the screws that moved the upper frame up and down to adjust it were extended so far that the force of the stroke offset the few threads that were turned into the socket by about .003". The threads would bind when running the screw upward due to this offset portion.

The socket component was held by a large resistance fit pin to an offset hole in a large wheel. We heated the dickens out of the material surrounding the pin and applied the output of a CO2 fire extinguisher to the exposed end of the pin--and off she came. The offset threads were trimmed by the machinist, and the parts were heated and cooled similarly for re-assembly. The moral of the story is that such a joint can, indeed, be manipulated, rotated, or undone.

Another way to get a hefty bond is to create a slick slip fit. Then apply three evenly spaced rows of center punch dimples to "strawberry" the O.D. of the inside piece for a tap fit into the corresponding hole. When the inserted piece bottoms out, rotating it slightly positions it so that the strawberry marks resist being drawn back through fresh material. But at this point, I think I like the heat/cool joint, for this job.

[sheepherder]

Originally Posted by ithacaartist

The interference fit is great--it will never be shot loose, and there's no mess to clean up.
<snip!>

Cool story!

I have one too...

Back when I was a millwright, one of my recurring jobs was rebuilding pulverizer gear reducers for the boiler in our paper mill. Coal dust got in everything (especially lungs ) and gummed the reducers up to the point they would break 3" shafts. To replace the bearings we'd heat up the cast iron gearbox, refridgerate the race overnight, and press the outer race (about 6" dia) in with a six foot hydraulic press. The outer race was an interference fit. You only had one chance to get it right. If you got it wrong, the race had to be torched in half and do it all over again.

To get the cast iron gearbox to expand the exact amount needed to drop the race in, we'd use two oxy-acetylene torches with rosebud tips. The millwright heading the job [me] would run a Tempilstik [pic below] over the area. The stik was like a candle but only melted at a specific temperature. 262º F in this case. When it melted & ran when you touched it to the gearbox, you [me again] dropped the race over the gearbox shaft opening, slammed a long steel sleeve over it, tilted it under the hydraulic ram, and started pumping like Hell!!!

I did at least a dozen rebuilds...I don't recall ever having a hangup...But there was evidence in at least one of the four reducers we had that it had happened (torch cut in the cast iron body)...

It was a four man job...And once the ram slammed down we all took turns pumping...Welders, millwrights, machinists - anyone walking by!!!

It was a stressful job...Lots of time spent by the machinist making the shafts...Expensive bearings...6" in dia, 3" wide races...

A reducer lasted about three months...We always had one standing by for when one of the two in use failed...The dust got in the oil ways and made a hard paste that had to be drilled out...

IIRC, the interference fit was ~1 1/2 thousandths [.0015"]...You couldn't let the reducer body get any hotter or it would take the hardness out of the bearing race...We had to have air hoses ready to start cooling the reducer down as soon as the press reached 20 tons...

They had all been painted gray originally...I had our painter paint them different pastel colors to tell the four apart...Baby blue, pink, light green, and gray...My way of rebelling against conformity...

[sheepherder]

Originally Posted by ithacaartist

Rich,

You could give GunBlack http://www.gunblack.com/ a call.

Dave -

His site has a form to fill out for a quote/response. I have not gotten a response.

I can sympathize. I don't want any more work either.

[ithacaartist]

Originally Posted by sheepherder

Dave -

His site has a form to fill out for a quote/response. I have not gotten a response.

I can sympathize. I don't want any more work either.

Uh-oh, your request is stuck in the "cloud"! I was a walk-in, initially, so didn't try internet contact. Better call 'em on the phone...

[sheepherder]

Originally Posted by Ron Wood

...I have a "fat barrel Baby" Luger project that ...I have been discussing...Just yesterday...a heads up on a "Fat Barrel" in 7.65mm that is threaded for the long receiver that I need which is being offered by Sarco. I have one ordered...

Ron - Whatever happened to this ordered barrel from Sarco???