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9/22/2017 12:11:25 AM
Posted: 10/1/2007 12:17:22 PM EDT
I seem to remember someone posting something about a poor man's bending jig that used some angle iron and washers from Lowes awhile back. I've tried searching through the sticky's and posts, but don't see any mention of it. Does anyone have the post or URL?

Thanks
Link Posted: 10/1/2007 12:22:11 PM EDT
Link Posted: 10/1/2007 12:28:10 PM EDT
Link Posted: 10/1/2007 1:42:43 PM EDT
This was on here a few weeks ago.fhttp://www.ar15.com/forums/topic.html?b=4&f=51&t=98202
Link Posted: 10/1/2007 2:45:24 PM EDT
Thanks all, that last post was the one I was looking for!
Link Posted: 10/1/2007 8:51:17 PM EDT
[Last Edit: 10/1/2007 8:55:15 PM EDT by JohnB_greenAK]
I've got all the parts for this myself....maybe $30 at Home Dopet.

Just waiting for my flat(s) to arrive....

I'm also thinking of buildng a "poor man's press" using the same iron stuff and a small auto bottle jack...
Link Posted: 10/8/2007 9:38:33 PM EDT
Got my kit and used the rear portion of the receiver (after removing the buttstock) to measure the gap in the outer jig element...

34.5 mm +/- .2mm

What I did was tightened the nuts on one side, and left the other side just tighter than finger-tight...I adjusted the width by turning the loose nuts 1/6th turn (outer one first, then the inner when expanding; inner nut first/outer one last when contracting) I eventually got it down to 1/12th turn and called it good.

Double-checked using the front portion, it fits with about 0.3mm gap (+/-0.015 when centered)

This is, of course, using my "calibrated eyeballs" and a $1.99 HF plastic micrometer...but it seems close enough for my purposes.

Heh heh heh....can't wait till I get some more time off....this might be the start of a frantic, albeit short-lived hobby, due to the supply of kits)...
Link Posted: 11/21/2007 12:10:40 PM EDT
Here is my version of the poormans flat bender. I used the flat with pre-bent top rails.
Just have to instal lower rails and center support and harden it. Made with 1 1/4 flat bar and 3 x3 x1/4 angle that I had lying around shop. I spent $6 for nuts and bolts. The bolts at the end of the flat bars helps support them so they don't bend.

Link Posted: 12/8/2007 8:01:38 PM EDT
[Last Edit: 12/8/2007 8:03:43 PM EDT by JohnB_greenAK]
Bent my first blank with the Home Depot Bend-O-Matic the other night...worked great! Easy turning of the 6 nuts (1/2 turn each, center-to-outer; 6 bolts = 1 each end, 1 in gripscrew hole, one in trigger hole, two in mag well), didn't even break a sweat.

Minor nudging with a vise and a Mk. I Hammer, Sledge to remove little oddities and all is well...

Until it came time to bend the upper rails. Measured twice, clamped tight in an angle iron frame, and again using the Mk. I Hammer, Sledge...they (in concept) turned out straight and well, but it *seems* that they might be a smidge too low. (I used the trunnions to measure, it still seems about 1mm too short)

What is the standard way to measure/mark/bend the uppers on a complete flat? Or should the uppers be bent before the flat itself?

I also noticed that I might be able to use the lower rails in some fashion to locate the uppers...anyone have a technique for this?
Link Posted: 12/12/2007 10:41:40 PM EDT
Sounds like your fubar'd there. The lowers must "gide" the bolt into the front trunnion to close and lock correctly and lowering them to compensate won't work. From all I've seen you need a side plate with the correct height to fold the top rails on to. I have not bent one myself, so I don't really know crap here but I don't see how you can fix one if it's off. Maybe just call it a learning experience and get another flate. Good luck.
Link Posted: 12/13/2007 1:42:55 AM EDT
Can someone post pics of it in use? Not quite sure how you're doing it.
Link Posted: 1/2/2008 4:58:40 PM EDT
I've built a "poor man's jig" (PMJ?) and tested it on some scrap steel pieces, with decent results.

I'm using flats with pre-bent top rails from cope's dist. and Romy G kits, and I've got one problem and perhaps one sweet idea.

Problem: the lower rails, in order to fit the bolt carrier, have to be moved perhaps 4 mm higher than the holes in the receiver flat would indicate! Yikes! Is this a typical problem? I imagine that spot welding the lower rails "high", where they belong, and then drilling the holes in the receiver flat all the way through the rails, will solve the problem. But could this weaken those holes too much?

Idea: spot weld the lower rails onto the receiver flat BEFORE bending it. This would be a piece of cake with the poor man's jig and pre-bent top rails, and it would let the builder use unmodified spot welding tongs!

The only problem I can anticipate is that the flexing of the flat while it was being bent could cause the rails to pop off or warp. Has anyone tried this?

Thanks!

Link Posted: 1/15/2008 8:49:37 PM EDT
I'm kind of new to the building of AKs, so please excuse my ignorance. But why couldn't the lower rails be mig welded in place in stead of spot welding???
Link Posted: 1/15/2008 9:11:15 PM EDT
tag
Link Posted: 1/30/2008 11:26:20 AM EDT
thats what I am wondering. I have a mig but no tongs. Until I saw this I was going to go for the laser cut reciever and weld the bends. I think I am not going to do that. I might just spend the $ and buy the jig.
Link Posted: 2/3/2008 10:25:22 PM EDT
so can the rails be mig welded?
Link Posted: 2/17/2008 11:52:19 PM EDT
Yes, you can mig weld the rails.. (done it)... but this poor man's jig screwed me over the weekend.

It bent my blank ok, but not in the shape I intended. The problem was the flat stock.. it's 1) not flat, and 2) not square.

This is my 2nd build btw, and I first tried pulling the flat into the jig with bolts... the bolt broke. Then I tried banging it in with a hammer. no luck.. creases but no bend. I started to bend it by hand and then saw that the flat was bent in the wrong places.

Arrghh... is one flat in the trash. Going to re-think this before I trash another flat.

Link Posted: 2/20/2008 4:05:30 PM EDT
Regarding top rails 1mm too low:


Originally Posted By milo47:
Sounds like your fubar'd there. The lowers must "gide" the bolt into the front trunnion to close and lock correctly and lowering them to compensate won't work. From all I've seen you need a side plate with the correct height to fold the top rails on to. I have not bent one myself, so I don't really know crap here but I don't see how you can fix one if it's off. Maybe just call it a learning experience and get another flate. Good luck.


I folded one and the top rails were almost 1/8" too low because the jig I bought was fubar and the seller dissapeared. I had to actually trim the hand guard to get the tongue to fit into the receiver once the trunion was mounted. I just made sure the lower rails were lined up, had to trim just a hair off of the cross bushing so the bolt wouldn't make contact, and tada it works great. Feeds fine, no issues whatsoever. Can't even tell it's too short.

1mm is not critical when you are talking about something with 2mm slop all over the place. Thats the beauty of the design.

Link Posted: 2/20/2008 4:09:15 PM EDT
[Last Edit: 2/21/2008 4:48:13 PM EDT by mykrowyre]
BTW, tried again, this time getting my 1-1/4" flat bar stock from lowes instead of home depot. The home depot stuff was not flat and the sides not square. It looked like hell. The lowes stuff has slightly rounded sides, but is very flat and square. I bought a brand new 3/8" drill bit and bolted the two bars together and drilled all of the holes. Just bent a flat and it worked great. Lots of work (I only used 3 pull bolts, so I had to bend the sides a little by hand to get past the 30 degree bend mark) so in the future I will use all 6 bolts to pull the flat into the jig.

Make sure you put bolts at the ends to hold the bar stock together... thats where I screwed up the first time... the stock bent and separated and my flat was trashed.







Link Posted: 4/17/2008 5:48:08 PM EDT
Another newbie question for the experts, I'm assuming the inside dimension of the flat needs to be 1.250". The flats I'm using are .041" in thickness, how do I calculate the inside dimension of the jig? 1.250+.082"(flat thicknessx2)=1.332" how much should I add for clearance maybe .002"-.003"? Any help is appreciated. I'm using 7/16" -A2 tool steel for the jig frame. I'm using ground flat stock instead of angle iron and milled end blocks instead of threaded rod, I just need to know what thickness to mill the the end blocks for the inside dimension of the jig, I'm thinking maybe 1.334-1.335 but I want to make sure first from someone experienced.

Thanks
Link Posted: 4/24/2008 11:07:54 PM EDT
I just guessed and added the thickness of the flat x 2 to the inside dimensions of the jig.
Link Posted: 9/7/2008 1:57:57 PM EDT
Relay to the question about mig welding the rails.
It could be done from the outside of the receiver after driling the small holes (size of the spot weld) in the receiver and spot welding the rails that way, filling the holes. It is mig welding method in car industry. I thing I'm going to do it this way.
Link Posted: 10/21/2008 1:53:44 AM EDT
[Last Edit: 10/21/2008 2:19:34 AM EDT by predatormaster]
Tag, elections comming!

ETA: Dumbass. Didn't even realize it's tacked!
Link Posted: 11/23/2008 6:41:39 PM EDT
Originally Posted By StagArmslower:
Relay to the question about mig welding the rails.
It could be done from the outside of the receiver after driling the small holes (size of the spot weld) in the receiver and spot welding the rails that way, filling the holes. It is mig welding method in car industry. I thing I'm going to do it this way.


I can be done but it's difficult. I have tried 4 times and failed each time. The problem is that the rails are heat treated and the receiver is not, so it's hard to get good penetration without burning a hole in the receiver.

A spot welder is the way to go. It's worth the $100 no doubt about it.

Link Posted: 2/19/2009 1:00:42 PM EDT
theres a method to welding on rails with a mig welder, and it will be even stronger when done right. the problem is its much more work........

just depends on if you like the original spot weld look vs a smooth out look.
Link Posted: 2/19/2009 1:51:12 PM EDT
Originally Posted By mykrowyre:
Originally Posted By StagArmslower:
Relay to the question about mig welding the rails.
It could be done from the outside of the receiver after driling the small holes (size of the spot weld) in the receiver and spot welding the rails that way, filling the holes. It is mig welding method in car industry. I thing I'm going to do it this way.


I can be done but it's difficult. I have tried 4 times and failed each time. The problem is that the rails are heat treated and the receiver is not, so it's hard to get good penetration without burning a hole in the receiver.

A spot welder is the way to go. It's worth the $100 no doubt about it.



Just heat treat the receiver before you weld.

IMO It's an AK AK's are rough, spot weld it.

However I've drooled over some rivetless, seamless, AK's that look like they were machined out of solid billet from the muzzle break to the Rear stock tang.
Link Posted: 3/17/2009 3:57:16 PM EDT
Does anyone have the Poor Man's Jig PDF file? It seems the website has gone offline. Thanks!
Link Posted: 2/7/2010 12:20:03 PM EDT
[Last Edit: 2/7/2010 1:22:52 PM EDT by StagArmslower]

Originally Posted By mykrowyre:
Originally Posted By StagArmslower:
Relay to the question about mig welding the rails.
It could be done from the outside of the receiver after drilling the small holes (size of the spot weld) in the receiver and spot welding the rails that way, filling the holes. It is mig welding method in car industry. I thing I'm going to do it this way.


I can be done but it's difficult. I have tried 4 times and failed each time. The problem is that the rails are heat treated and the receiver is not, so it's hard to get good penetration without burning a hole in the receiver.

A spot welder is the way to go. It's worth the $100 no doubt about it.



I have done it this way. I drilled 1/8" holes along the rails approximately the same places as for spot welding and set the welder pretty high so the metal floats flat with little build up. I started with the wire inside the hole and kept the wire there until little mushroom was created on the surface of the receiver(about 2-3seconds). Actually I wanted to keep those little hills but at the end they were not even so I grind them flat. I've gotten nice signs of good heat on the inside of the receiver.

http://www.newsbleed.com/documents/grasshopper_jig_gunco.pdf
The pdf file for home made jig.
I made it similar to it but I welded it. This allow me match the dimensions closer



Link Posted: 2/12/2010 6:47:58 AM EDT
Originally Posted By StagArmslower:

I made it similar to it but I welded it. This allow me match the dimensions closer



I thought those bolts looked a little iffy. I think some spacer blocks would make setting up the jig a lot easier.

Link Posted: 2/24/2010 11:19:02 PM EDT
Originally Posted By mstang88s:
Here is my version of the poormans flat bender. I used the flat with pre-bent top rails.
Just have to instal lower rails and center support and harden it. Made with 1 1/4 flat bar and 3 x3 x1/4 angle that I had lying around shop. I spent $6 for nuts and bolts. The bolts at the end of the flat bars helps support them so they don't bend.

http://bentbarrel.com/pics.JPG


THIS.

Done three flats this way with pre-bent top rails. Worked just peachy. Get the stock from LOWES not home depot. Home depot's stuff is not square.
Link Posted: 3/2/2010 2:07:56 PM EDT
Sorry if this an old question I didn't see. Two things. Can the rails be riveted on or is welding the only thing that works? And, how can bend the top rails so I can use any flat out there?
Link Posted: 12/16/2010 7:01:43 PM EDT
Originally Posted By OvisCanis:
Sorry if this an old question I didn't see. Two things. Can the rails be riveted on or is welding the only thing that works? And, how can bend the top rails so I can use any flat out there?


also wondering this.
Link Posted: 9/30/2012 10:22:33 PM EDT
[Last Edit: 9/30/2012 10:24:46 PM EDT by mykrowyre]
Originally Posted By OvisCanis:
Sorry if this an old question I didn't see. Two things. Can the rails be riveted on or is welding the only thing that works? And, how can bend the top rails so I can use any flat out there?


I don't see any reason you couldn't rivet the rails.. I have seen some that were bolted in. One of them has a rivet... only problem is it would look like hell, but if you don't care I guess it doesn't matter. Also I think you'd have a rivet in the way of the selector so you'd need to hammer it flat.

As for the top rails, I bent the top rails on my first build. It was a bit of a PITA. I used a bending jig which I found out later was f#$d up, and the top rails were too low. I can't tell you how angry I was since I purchased that jig by a builder on this forum who was making them. Anyway, I got the rifle working in fact I still own it. You can't tell the top rails are too low until you try to install new furniture and find you need to dremel off quite a bit of it. Anyway, I bent them with a hammer, and trimmed them with a dremel. I went thru a ton of dremel disks and wheels getting those upper rails trimmed.

Now I buy flats with pre-bent (and stepped) top rails. It's soooo much easier, and the end result looks better too. Not much of a cost difference (if any) so why not!



Link Posted: 9/30/2012 10:47:08 PM EDT
[Last Edit: 9/30/2012 10:50:37 PM EDT by mykrowyre]
Bending the cheap way... have done a few of these now, all turned out great

Lining everything up with a caliper, make sure it's centered! Spread of angle iron is 1.35"


Tighten 1/4" turn each ... flat was greased before hand (not just WD40)


I heated the backing plates with a torch until blue in color and then quenched in cold water. This hardened them enough to prevent them from bending (a problem with the last few builds I did this way).


If you find one side is lagging behind, tapping gently 20 times with a light hammer will get things moving... notice the ends are not keeping up with the center...





Link Posted: 5/21/2013 9:43:43 PM EDT
Go to gunbroker and search for bending jig and you'll find one for sale just like pictured above. Not mine, just sharing the info. I traded the guy some ammo for one and they only cost around 50 dollars. Works like a charm.
Link Posted: 6/26/2013 12:02:07 PM EDT
[/quote]
I thought those bolts looked a little iffy. I think some spacer blocks would make setting up the jig a lot easier.
[/quote]

They are iffy. Mine bent on my first pseudo-attempt on some extra sheet just to see if it'd work. I ended up using smaller bolts at the bottom of the angles like jack screws, but I think spacers would be the way to go, and I'll probably do this. It also opens up the possibility to use different width spacers and use the same bending jig angles to make custom length 1911 mags, Colt Mustang mags, Spanish Ruby mags, etc. which is the next thing I'll try and do with it.

My first flat turned out fine, BTW.

Link Posted: 9/9/2013 2:57:28 AM EDT
The first version is VERY easy to make, and works phenomenally!! The last one I made, though, I made about an inch long on each side of the flat clamp and ran two extra bolts. This greatly helped with stability and alignment. I also ran about 3" long on each side of the fold bars and again ran an extra bolt in each side. I believe the four-bolt fold and the six-bolt flat clamp are the way to go if you want to do a poor man's jig.


- CK
Link Posted: 7/11/2014 7:02:20 AM EDT
[Last Edit: 7/11/2014 7:09:59 AM EDT by Ryan_in_SD]
I'm a bit of an expert on poor mans bending jigs. Ive made several versions over the years. My latest version works really well. I put a bunch of pictures up on amazon if you want to see what the design looks like. Its an evolution of the original grasshopper angle iron bending jig.

http://i.imgur.com/LozTHRx.jpg
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