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Discussion Starter #1
:help2: I am/was considering making my own flatsfrom basic sheet steel , I've found a sheet metal brake that'll handle the bends in 4130 steel but the throat is too thich to handle all 4 bends in the metal without having it run into the brake itself ... my question is as follows(pay attention pookie):notworthy .. what if you split the pattern down the center and bend a right half and a left half , center being in the middle of the magwell area, do the 2 bends needed and tig weld it back together down the center ,using a 3/4 inch copper bar as a fixture ,having the least amount of welding to do it that area ...does this sound at all feasible ??? considering that most of the force of the receiver is taken along it's length and the trunions would ultimately hold the sides together anyways??? :dunno:
 

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Discussion Starter #2
I was also looking at being able to weld the side rails on to the right and left side of each ,before welding the halves together, being as it would be a straight shot (no trying to weld in a tunnel) and you could line them up real nice with the front trunion ramps:dunno:
 

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Discussion Starter #4
just stubborn I guess, or just trying to think too far ahead, I thought being able to have free access to the guts to be able to weld and make it look really nice on the inside , at the same time keep the outside of the receiver nice and flat with minimal grinding would be easier is all... I did see sks's post on bending the quick and dirty way and that's what got me thinking about all of this ....besides sheet stock costs less, 33.00 worth of 4130 plain sheet would make almost 5 or 6 flats ....guess I'm getting cheap in my old age ......:lolup:
 

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Happy Camper
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You wouldn't be referring to this brake would you:

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=39103

???

Some have gotten not-so-square bends and it seems the reason is the brake is just light-weight enough to require reinforcement.

Others have tried this with Tapco flats and results are mixed. General consensus is that it isn't quite up to the job and you need to buy some bar stock from HD to reinforce it. Since you're talking about welding, that shouldn't be a problem. True, you are practically rebuilding it, so the $21 gets you the precision-milled flat surfaces and properly aligned hinge - still a good bargain.

I've read that gratuitous use of C-Clamps help too.

I have picked up one of these but have not tested it yet.

It seems that you would be better served by using 1.25" bar stock and doing the SKS method of bending (via a vise). A shop vise DOES have the capability of bending flats. You just need to go slow and grease it, and be careful.

FWIW, I know that *I* myself could not weld it properly, I haven't the welding skills. I'm just a crazy guy with a garage full of toys, er, tools. :)

To address your question - you COULD weld it I think. If there were a way to minimize and/or recover the metal after flexure, then it would be doable. The chances for failure are high - the sheet metal will undoubtedly suffer a great deal of heat flexure that I don't think can be avoided. That's why silver solder won't work for welding trunions, and the laser-cut weld-up flats are such a bugger to use.

BUT it would be no worse than using a weld-up flat. I think the key would be a huge chunk of copper to absorb the heat, and doing the spot-weld alternating on both ends, letting it cool, another spot weld, etc. etc. I remember reading that method on one of those "how I welded my laser cut flat" posts somewhere. Someone with better welding skills can better explain this (WinnR knows someone).

hth,
- Jerry
 

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Discussion Starter #6
was thinking more on this brake --- seems more heavy duty ..... http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=90606
I've got one of those light duty ones from 20 years ago but just haven't tried it on 4130 steel yet ... online metals has 3/4 by 3/4 copper bars 12 inches long for about 12.50 each -- thought that would be good for welding fixture
 

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I'll be interested to see what this guy comes up with. Seems that he has taken every idea he is selling off of someone else. Glad to see he gave credit to HCPookie, but what about Max?
 

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The reason brakes don't work is there's too much slack between the jaws and the bending bar. I built RVs most of my working life and used brakes on a daily basis. They are fine doing 22-26 gauge aluminum and light sheet metal but if you put heavy steel in they will flex back and leave a bad edge. C clamps will strengthen the vise part but the hinges will back out a few thousandths when you put a few thousand PSI on them. I personally wouldn't even try to bend .040 sheet metal on a brake. If I was carguy I would take that brake money and invest in a mig welder or arbor press. Then build a nice jig box and do it right.
 

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Gunco Irregular
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I agree with Snazi. I bought a larger brake from Harbor Frieght (not the one in either link) and there is too much play and not enough clamping force. IMHO If you're going to spend $159 you would be better served with a bending jig from Stickermanhttp://www.jtagconnection.com/flat_jig.htm or DPH http://www.dpharms.com/. Although you'll need a press you will need one anyway for barrel pressing.
 

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sumbitch
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sumbitch
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oyea never could have built my aks without the help of silverdollar after reading his threads on building aks and learning how to do it.i then had to learn how to build the flats my self .
 
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