Blueprints for a respectable solid AK bend jig?

[Kawgomoo]

there really is no magic to bending flats. receivers are an inch and a quarter wide. theres your plans.

the hard part is locating the flat in the jig, so the sides line up. remember, the fcg holes are already spotted.

the jig mentioned earlier in this thread, i see no provisions for lining up the flat. Sure you can do it manually with a machinist rule everytime...but why?

time, materials and frustration the flat jig isnt worth building. esp with these 80% polish blanks floating around.

build yerself the rivet jigs, thats where the big bucks are spent. {and even ak builders rivet jigs dont come with ALL the pieces you will ever need}

[kcstott]

I hope you weren't talking about my jig not having a means of locating the flats.
This ain't my first jig and there is a set of dowels in there that align the flat the same as the AK builder jig does. Two dowels in the magazine opening and one in the rear trigger guard rivet hole. My flats are located within .003" every time. I also have a second set of pins for 74 receivers

I actually think AK builder has the prices mixed up on the jigs. I think the flat jig should be $250 and the rivet jig $169 the rivet jig is much easier to build.

[JAGGUY]

That's a serious jig!
I built this one for $26 in material and a couple hours time 6 years ago.
It only did Tapco flats but that was what was available at the time.
Bent a bunch and still shows no wear but I moved on from AK's since complete parts kits with barrel aren't $99 anymore...

[Apec]

It used more just as a gimmick then anything else. It really is use just to get someone to buy the part and nothing more in a lot of cases. And people will pay through the nose for some gizmo made from TI just because it's Ti.

I've seen a full bolt action receiver made out of TI, Obviously firing pins, Scope rings and bases. I just have a severe distaste for that material. I had to set up two CNC machines. One that made TI knife blades the other made the pomels for the knives. My thing with TI is it's not worth the weight savings. Unless you're building air craft or aerospace parts it ain't worth the expense. Obviously my opinion is biased so take it with a grain of salt from a guy that had to machine this stuff for closes to ten years.
Don't get me wrong though in the correct application it's great material I think it's just to buzz wordish even still today. We made a Knife blade out of the stuff just so we could say "solid Titanium" which also meant you knife was an over priced piece of junk. It won't hold an edge, it a pain to sharpen because it's soft yes soft Titanium is soft compared to tool steel. it's also springy as hell and doesn't conduct heat worth a darn so your cutting tool soaks up all the heat and it goes dull fast. I guess you can see where my distaste for the material comes from. Proper application and I'm fine with it.

Now I will confess that I have been thinking about a stainless AK. bead blasted flat and left that way. Stainless rivets, stainless everything. That would be a hell of a lot of work.

SVI's made 1911 frames from Ti and still offers them, if I recall.

But I can attest to Ti being "the best thing since sliced bread" in the knife/gear/edc world. Seems as if 6Al-4V is the gold standard, and every high end knife manufacturer/custom maker has a lineup of blades with titanium framelocks and hardware. Blades are rarer, but you do see knifemakers putting out small ones with carbidized edges and whatnot.

[kcstott]

Ti for the handles and hardware sure but not for a blade where the cutting edge is Ti. The material is just to soft for a decent cutting edge.

[Ryan in SD]

Holy crap kcscott, thats one hell of a chunk of steel. How long did it take to mill on that knee mill? How big is that EM and what was the depth per pass???

You must have a lot of patience

But it looks good and beefy, good for many lifetimes.

-

Hakweye, I wouldnt use titanium for this, complete wrong type of metal for this job.

Maybe something like o1 for the die and 4140 for the punch.

Nothing wrong with mild steel unless you are talking about doing more than 50 flats and have a good design. (which case you probably are an 07fll and have funding to make a lot)

Its only going to be as strong as its weakest point. The punch where the radius is formed should be as beefy as possible without making it too difficult to remove the receiver once its done. Ie. sliding the receiver off the punch past the dimples.

Good luck!

[kcstott]

Holy crap kcscott, thats one hell of a chunk of steel. How long did it take to mill on that knee mill? How big is that EM and what was the depth per pass???

You must have a lot of patience

But it looks good and beefy, good for many lifetimes.

I was paid to stand in front of a knee mill for twenty two years so a few days was no big deal.

End mill was a six flute high helix solid carbide And I was taking about .150" depth per pass.

Spread out over a three month span it was actually only six days or so total.

I started machining it, Then a build party came a long and I said screw this, then I had a spare flat that was bent at the party and wanted to build a pistol after 858Casper showed off his at the build party. So I tried to use the flat I had it was a Tapco and turned into a banana by the time i was done. So demill and order a flat and get back on the machine cause I need some tools.

I got the flat jig finished bend my first flat had to add clearance for the mag stabilizers. Then I broke my bolt cutter riveters and said ok now I need a rivet jig, So I built that. Then I needed a barrel and trunnion support, Built that. Built everything I have to assemble AK's as I have way more time then money but not much. And due to the two build parties I've been to I was able to gain a lot of experience putting together these rifles and have since been able to build a few in the garage for paying customers. Thats what paid for the park tank. and it's what allowed my to get into Cerokote.
It's fun. It get's more people shooting and having fun and I get to spend money on tools

[Ryan in SD]

I was paid to stand in front of a knee mill for twenty two years so a few days was no big deal.

End mill was a six flute high helix solid carbide And I was taking about .150" depth per pass.

Spread out over a three month span it was actually only six days or so total.

I started machining it, Then a build party came a long and I said screw this, then I had a spare flat that was bent at the party and wanted to build a pistol after 858Casper showed off his at the build party. So I tried to use the flat I had it was a Tapco and turned into a banana by the time i was done. So demill and order a flat and get back on the machine cause I need some tools.

I got the flat jig finished bend my first flat had to add clearance for the mag stabilizers. Then I broke my bolt cutter riveters and said ok now I need a rivet jig, So I built that. Then I needed a barrel and trunnion support, Built that. Built everything I have to assemble AK's as I have way more time then money but not much. And due to the two build parties I've been to I was able to gain a lot of experience putting together these rifles and have since been able to build a few in the garage for paying customers. Thats what paid for the park tank. and it's what allowed my to get into Cerokote.
It's fun. It get's more people shooting and having fun and I get to spend money on tools

Dayum, that must be a pretty solid knee. I think the one we have at work does .070 with a 1/2 at a tolerable pace. .150 with 3/4 is boss.

Hey btw, how do you make money building guns? Are you licensed or do you do everything minus the receiver? Sounds like fun, I've considered going the 07 route. As for now, I just do accessories.

Keep on truckin

[kcstott]

That's what 6 flutes and a high helix allows you to do. If it was a four flute standard helix HSS I would not be able to take anywhere near that deep of a cut. The six flutes smooth things out. And I did leave a good amount to clean up.

The way I was taught to machine was to push the tool and the machine for everything it's worth short of breaking anything. and if your chip wren't blue you're not taking enough. So yeah you clamp stuff down real tight get the coolant flowing and go for it. Adjust your rpm's and feed rate till your are taking as much as you can as fast as you can with out shaking the crap out of the machine.

The pics don't really show how i cut the slot
What I did was take a full width cut right down the center I started out at .100" depth of cut at about 600 rpm On the conservative side. Then I bumped it up to .130" then .150" and increased the rpm's to right around 1000 but I had to slow down the feed rate.
Once the slot was cut i could start to widen it and that is where the depth of cut dropped off. I was taking maybe .050" or .070" but using the full length of flute .850" deep.
Conventional cutting only and just pushing through. I don't have time to tickle this stuff So I go to town hogging this stuff out. Yeah I'm going to dull a cutter but a regrind is cheep. I guess that the Job Shop machinist in me. It's not how you make the part but it how fast you make it. and if you burn up a $50 endmill on a $5000 part no one cares as long as you got it done ahead of schedule.
I'v egot a fixture in my garage that I spent some good money on. It allows me to sharpen my endmill and I don't mean the tips I mean the flutes. So once a year I go through all my cutters and set my fixture up on a saturday and do nothing but sharpen endmills and I'm good for a year. I've got a diamond wheel too so I can sharpen my carbide as well.

You make money just like a build party. Charge a fee for your time, shop, and tools.
No FFL needed as long as you don't keep the receiver with you while the owner is not there. Lot's of people need barrels threaded, muzzle brakes welded, Can't wait for a build party, Need a scope mounted. Need something fixed that they can't figure out.

Yeah I'll get my 01 gunsmithing only FFL here soon but right now as long as don't hang on the the serialized parts I'm good.

[hawkeye]

Soory about that I got bussy and forgot all about it.

Any way so the base is 12"X 3"X 1.75"
The slot is .875" deep the step from the top down is .375" deep This allow the use of a .5" thick clamp on the pusher that will locate before the bend starts.

Now the dimensions for the base are 1.255" at the bottom and 1.3375" at the top

The plug is 1.258" and the clamp plate is 1.250" so there is a bit of clearance on the the clamp but as you can see there is only .0008" clearance on the plug.
.03937" X 2 = .07874" +1.258 = 1.3367" Now Curtis's flats run a touch thiner like .001"- which is fine it's sheet metal, that's normal. And as the sheet bends around the plug it's going to stretch but only in the area that is affected by the radius. I also put about a .020" radius on the plug as I didn't want a dead sharp corner but I also didn't want a huge radius either.



The top of the base has a .125" radius cut on the top to help roll the material into the die.

Also the plug was made from 3/8" X 3 A36 welded together like an I beam.
This was then machined to square everything up and make the top and bottom parallel with each other.
I used 3/8" cap screws to bolt down the clamp plate but the AK builder jig uses 5/16" I also drilled clearance hole in the base to clear the head of the bolts. Then I tapped those holes 3/4" 10 and used large cap screws to separate the two pieces after a the bend is made.

Thats about it. the clearance on the plug was just try it and fit it. until it was right. I still need to clear it out a little more.

Now the critical thing is you need to get the slots machined one center of each other as close as you can to prevent tolerance stacking. I shot for within .001" and was able to hit it. The other thing is you don't want to much clearance on the push to the die base. .001" is more then enough as you can see I kept mine at .0008" a little on the tight side. Things wear and as long as I keep this thing oiled it will last longer then me and only grow .001" at the most.


I guess I should draw up a set of prints and sell them for like $5 a set. For everything though. Plinker jig, flat jig, and trigger guard jig, and front trunnion support jig.
I guess I found my new project.

Thanks. I appreciate you taking the time to get back to me. I'm looking forward to starting this project in the next few weeks..

[Ryan in SD]

That's what 6 flutes and a high helix allows you to do. If it was a four flute standard helix HSS I would not be able to take anywhere near that deep of a cut. The six flutes smooth things out. And I did leave a good amount to clean up.

The way I was taught to machine was to push the tool and the machine for everything it's worth short of breaking anything. and if your chip wren't blue you're not taking enough. So yeah you clamp stuff down real tight get the coolant flowing and go for it. Adjust your rpm's and feed rate till your are taking as much as you can as fast as you can with out shaking the crap out of the machine.

The pics don't really show how i cut the slot
What I did was take a full width cut right down the center I started out at .100" depth of cut at about 600 rpm On the conservative side. Then I bumped it up to .130" then .150" and increased the rpm's to right around 1000 but I had to slow down the feed rate.
Once the slot was cut i could start to widen it and that is where the depth of cut dropped off. I was taking maybe .050" or .070" but using the full length of flute .850" deep.
Conventional cutting only and just pushing through. I don't have time to tickle this stuff So I go to town hogging this stuff out. Yeah I'm going to dull a cutter but a regrind is cheep. I guess that the Job Shop machinist in me. It's not how you make the part but it how fast you make it. and if you burn up a $50 endmill on a $5000 part no one cares as long as you got it done ahead of schedule.
I'v egot a fixture in my garage that I spent some good money on. It allows me to sharpen my endmill and I don't mean the tips I mean the flutes. So once a year I go through all my cutters and set my fixture up on a saturday and do nothing but sharpen endmills and I'm good for a year. I've got a diamond wheel too so I can sharpen my carbide as well.

You make money just like a build party. Charge a fee for your time, shop, and tools.
No FFL needed as long as you don't keep the receiver with you while the owner is not there. Lot's of people need barrels threaded, muzzle brakes welded, Can't wait for a build party, Need a scope mounted. Need something fixed that they can't figure out.

Yeah I'll get my 01 gunsmithing only FFL here soon but right now as long as don't hang on the the serialized parts I'm good.

Good stuff

[kcstott]

and use a 5/16" or 3/8" ball end mill for your clearance cuts along the base of the plug leave a land about .080" up by the mag stabilizers.
And I used 1/8 and 5/32" dowel pins for the alignment holes. 1/8" in the mag well and 5/32 for the trigger guard hole. fits perfect.

[asheron2]

Wow you guys are making this out to be rocket science j/k. I used two pieces of 3"x4" rect tubing. Put two bolts through it at each end and use nuts to adjust and hold the width. Dye is 1.25"x3/4 sandwiched on both sides and relief cuts made with a grinder, drill, and some hand filing. I don't even need a press because I use 3/4" bolts to sucks the due through the jig. It's successfully made about 15 very nice looking AKs.

Thing was practically free because I used scraps and extras lying around.



This was the first receiver it made, jig now bends cleanly around the mag well area.

[kcstott]

Well no offense but I didn't want a half arsed jig that could deform. I've seen the angle iron units and the tubing units I don't care for the design. Don't get me wrong they will work but for how long till a component needs to be replaced.
yours with 3X4 tube seems friggin heavy duty

[asheron2]

Well no offense but I didn't want a half arsed jig that could deform. I've seen the angle iron units and the tubing units I don't care for the design. Don't get me wrong they will work but for how long till a component needs to be replaced.
yours with 3X4 tube seems friggin heavy duty

Yeah it was left overs from a boat trailer...........probably overkill for a jet boat trailer too. The beauty of having a jig with the bolts setting the width is you can adjust it if you need too. Truly the sweet spot is a little different depending on manufacturer(I always bend my friends first ) and set the width with calipers. Ive built a jig that was milled and machined for my HK G3 Builds, but the jig ended up being too narrow..........it took a long time to build and was frustrating. I too a 1" thick plate I found and welded two 3/4" rods too it at the new distance and it worked much better. This new jig that was free(made from Scraps), and only took about an hour to build did a much better job....

Sometimes these things arent worth the time and financial investment because one that looks like !@#T can build a nice firearm and last indefinitely(ive got a little khyber pass mentality in me), or at least that what i've found from making all my equipment from scratch.

HK Jig(didnt work very well and took lots of time, the side rails started out as 1.25" tall and I cut them down to 3/4".........I'm cheap and all the materials were free and scavenged)