Author Topic: How is the fixture, that the fore end screw screws into, attached to the barrel?  (Read 492 times)

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Offline ncsurveyor

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How is the fixture, that the fore end screw screws into, attached to the barrel?

Trying to plan something.

Offline Busta

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SPOT (resistance) welded, 4 places. You wont be able to see these spots (protrusions) from the outside. The strength of these welds will be determined by how well the welder was set up at production. I have never had a problem with one, but others have had them break off due to cold welds.
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Offline wtroger

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As stated they are welded on the same as the barrel pivot lug it appears to be mig welded and it looks to have been run pretty cold trying not to change the strength of the barrel steel. The fact that they break off occasionally would also indicate a cold surface only type weld instead of a deep penetrating weld.

Offline ncsurveyor

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Since my background is in theoretical and not mechanical, if someone wanted to reinforce said fixture without changing the strength of the barrel, how would this best be accomplished?  Would additional spots do this?

Basically looking at making a point on the barrel the focal point of recoil as opposed to the frame.  This existing fixture would be an obvious point in lieu of attaching a lug near the chamber area. Although, attaching a recoil lug of some sort near the chamber would be more beneficial to the ultimate project.

given that, is it safer to weld nearer the chamber?

Thanks for your help so far.

Jeff

Offline quickdtoo

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The underlug is tig/mig welded, the forend stud is just spot welded(resistance as Busta said) on, two very different methods of welding. The forend stud has been known to come off, there's a warning on adding weight to the forend in the FAQs for this very reason.

I think I'd rough up the area adjacent to the stud mounting pad and as much under the edges as you can, degrease and apply some JB weld to reinforce it. Any actual welding on the barrel would damag/affect the bore, I'm sure.

Tim

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The forend mounting stud is attached to the barrel by 4 small spot welds about 1/8" dia so the additinal weight was too much for them to handle. .....


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Offline peeper1k

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Since my background is in theoretical and not mechanical, if someone wanted to reinforce said fixture without changing the strength of the barrel, how would this best be accomplished?  Would additional spots do this?

Basically looking at making a point on the barrel the focal point of recoil as opposed to the frame.  This existing fixture would be an obvious point in lieu of attaching a lug near the chamber area. Although, attaching a recoil lug of some sort near the chamber would be more beneficial to the ultimate project.

given that, is it safer to weld nearer the chamber?

Thanks for your help so far.

Jeff

Jeff, if you are really set on adding strength to your stud, you'll have to either keep it simple and smart and do what Quick' says and use an epoxy of sorts.  There are some impressive products made today (industrial ).  Probably 10x  $$ more than JB Weld, but Strong.

If you want to get a tad over-board, you COULD do whats commonly done with c-moly' thin-wall tubing, but instead of welding and ruining your bbl you sweat the gusset you'll be making.  I've done dozens of front globe-block sights this way.    A semi-rectangular .050" thick +/-  section of 4130, holed in it's center to fit over the stud, heated to forming temp with a small oxy flame so as to allow forming to bbl contour like it's been vacuumed formed.    When you are satisfied, de-blue the contact area,  mini-clamp using spacers of small dia to minimize contact areas, Heat the entire bbl in an oven to 400 degrees, remove,  use a twin flame propane torch to heat the bbl and gusset to silver solder flow temp ( a tad above the 400 degrees already there, do the flow, let it cool, finished.  Inlet wood. Bed fore & aft prior,  to maintain original position.

The oven use prevents distortion from a local heat, the silver solder is low temp so it won't ruin any original hardening.  It's damn strong.  I repaired $500,000 slide presses and die sets this way for ten years in another life, keeping within it's .0005" run-out  limits.  Square inches of contact area is the desired goal. Forget about a butt joint using silver.  I sweat on my front sights for my long range hardware.  This method imposes a zero run-out.

Have I done this this to my Handi?   Heck no. Geeese, this is a lot of work. ;D  I epoxy bedded my fore, and I have a butt-ugly blacked worm clamp around the wood & bbl to handle the extra weight.  A recoil lug here would be somewhat useless perhaps, since there is no energy path around the action to the butt.  I was concerned since I shoot this particular 22" 45-70 standing only, and the weight of MY ARM holding onto the forearm added a LOT of weight when 500 grs go out at 1450.  IMHO, adding some slight weight into the forearm was less than my arm hanging on for dear life during a recoil arc, but maybe it's a toss-up.  Don't know, but so far over 2000 rds lighted off.  The gun shot sub  2" groups at 100 yds before the strap, and still does sub 2" groups after.   This method may stink-big with a  tack-driver sub moa, but heavy lead with a peep it's ok so far.

I'm wondering if guys have had problems with using a sling to carry in the field, given the heavy load imposed on the stud in that scenario.  That's got to be an area to look at perhaps.. ?

Offline quickdtoo

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Or do it the easy way and make a barrel band like Larry did for his .30 Carbine barrel!!  ;)

Tim

http://www.gboreloaded.com/forums/index.php/topic,113860.msg1098364421.html#msg1098364421
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Offline peeper1k

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Or do it the easy way and make a barrel band like Larry did for his .30 Carbine barrel!!  ;)

Tim

http://www.gboreloaded.com/forums/index.php/topic,113860.msg1098364421.html#msg1098364421

That's sweeeeeet !  Some guys don't want to see anything going on, but for me, Function over form, Labor over use.  I did a bbl band on a 458 almost like that to attach a sling, but still, I sweated it on to prevent it coming loose.  It was going to Africa for a month and would see rough use., so I thought fail-safe would be the way to go.  Bummer that i wasn't the guy going tho.. .

Hmmm, that was a good link, Quick'.  I wasn't going to ever deal with the Handi in a serious way, given the nice low dollar cost, but darn,  my "New-to-Me" Handi's are coming to be the most fun to shoot I have.  I don't know if Quick' has done me a favor or done me a curse, but I can hear the drill press starting to run even now.

Quick', darn'it, I was HAPPY with my clamp.. .but now I've got to do some tinkering.   I had such a nice weekend planned.

Offline quickdtoo

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Offline ncsurveyor

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A recoil lug here would be somewhat useless perhaps, since there is no energy path around the action to the butt. 

that's what this whole excersize is about.  I'm onto something. Just trying to work out the bugs.

And after Quick mentioned the JB, things got a little clearer.

Will be getting some tools together.  I hope to have this thing in progress, soon.  More to come.

Thanks for the replies.

Jeff