Building AK receivers from a Tapco Flat using a 555th Flat Bending Jig

[Quarterbore]

TAPCO FLATS

http://quarterbore.com/images/555thjig-tapcoflat.jpg

The flats shown above are one example of AKM stamped receiver flat that are being manufactured and sold. These are not considered to be firearms as these receivers are less than 80% complete and they require considerable work to be formed into a functional firearm.

Bending the Flats to make a receiver - The 555th Jig

I have a 555th Jig that is purchased and in the mail. There are several manufacturers of AK-bending Jigs and in general they are all quite similar in design and function. I will update this info when I get the jig but following is some general pics and info:

http://quarterbore.com/images/555thjig-w-alignmentpin.jpg
Note: This jig has additional alignment holes added as described below!

Instructions with pics (http://quarterbore.com/images/555thjig-bending-a-flat.doc)

Plans to build your own (http://quarterbore.com/images/555thjig_print.pdf)

ZIP File with pics, CAD drawings, and plans in TIFF format (http://quarterbore.com/images/555th_jig_v2.zip)

Sample Free CAD Programs to view CAD files above (http://www.infograph.com/products.htm)

Details on how to add the alignment pins as shown in pic above...


Advise from 555th himself!

I have never really had any trouble lining the flats up, but I've seen where some guys have. Today I drilled and tapped the bottom plate on BlueJack's jig and used 8-32 bolts to attach the flat flat to the bottom plate. It worked great. I bent two flats in a row and never measured any thing on the second one. Here's how to do it if you're interested;

Attach the flat flat to the jig and line it up perfectly with a rule or slide caliper. Line in up in the front, then snug the front bolt. Then do the rear and recheck the front.

Once it is centered, Take a marker and mark the flat along side the bottom plate and put some index marks on it and the plate.

Take the bottom plate loose from the jig and line the flat up with the plate and clamp it.

Drill the alignment holes down through the bottom plate with a #29 drill bit and take the clamps off.

Tap the two holes and your done.

[Quarterbore]

Time to buy a Hydraulic Press!

I have bounced between buying a 12-ton or 20-ton press and I finally decided funds were tight enough to go with the 12-ton as more portable unit and I may add a bigger press in the future if I find a need.

I did an extensive search and I found a number of people that indicate that they have used presses in the 6-ton range to do AK rivets but the 6-ton will not work for pressing barrels unless it has more operating length then the ones sold by HF. In general, however the consensus is that a 12-ton H-press is adequate for most AK Builds. In this context, I purchased a 12-ton press as follows.

http://quarterbore.com/images/h-press_33497.gif
http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=33497

Following are some specs of this press:

Working distance: min: 3-1/4" - max: 28-1/4"
Width between channels: 16-3/8''
Overall dimensions: 53-3/16" H x 19-1/2" D x 19-1/2'' W
Shipping weight: 122 lbs.


Following are some other reviews and oppinions on the subject:

What is the minimum size (http://www.gunsnet.net/forums/showthread.php?t=211171)
Responses: 6, 10, 12-ton (with a vote for wishing they had a 20-ton)

Problems with a cheap press - SLOP (http://www.gunsnet.net/forums/showthread.php?t=209579)

http://www.gunsnet.net/forums/showthread.php?t=195455

EDIT 19-Sept-2005

I have used my 12-ton press quite a bit and I do love it! I have used it to help me with lots of tasks including various AK projects plus building or swapping out parts on the FnFal and AR-15 as well. It has also come in handy anytime I need a piece of steel or metal bent and it was put to use this summer when I built a deck on the back of our hose and I needed to form a couple hangers....

Still, there is one limitation with the 12-ton press! Ther just is not a lot of working room under the press and there is time while working with a flat bendking jig or even plinker's rivet press where a little extra room would be nice to have. In that context, I just purchased a 20-ton press forr future projects. Funny however, I have the press in the shop but I spent a few quality hours this weekend working on my current build and I still used the 12-ton press instead of taking the time to get the 20-ton set up.

The 12-ton is nice as it is lite enough to be portable by myself. The 20-ton press is much heavier and I do not see me transporting that monster to build parties but I have noticed a good amount of flex in the 12-ton under pressure (Romanian Barrel pin anybody) so I will be curious if I cee that with the 20 as well... again, not that the 12-ton didn't do any job I have asked of it!

[Quarterbore]

Photos and directions of the bending process...

Parts of the 555th jig
http://www.quarterbore.com/images/555th-flatbend-01.jpg

Mounting the flat to the jig
http://www.quarterbore.com/images/555th-flatbend-02.jpg

http://www.quarterbore.com/images/555th-flatbend-03.jpg

http://www.quarterbore.com/images/555th-flatbend-04.jpg

http://www.quarterbore.com/images/555th-flatbend-05.jpg

http://www.quarterbore.com/images/555th-flatbend-06.jpg

http://www.quarterbore.com/images/555th-flatbend-07.jpg

IMPORTANT NOTE
The pic above shows the flat mounted finger tight... Before the bolts are tightened with a socket the flat must be centered in the jig. This is the single most critical step and I used a set of reloading calibers to measure between the holes on each side of this rail to ensure that the flat was centered...

http://www.quarterbore.com/images/555th-flatbend-08.jpg

NOTE: The flat was lightly greased using axle grease on all sides before bending. This is important as it will help prevent streeching of the receiver or deforming the holes in the receiver.

http://www.quarterbore.com/images/555th-flatbend-09.jpg

http://www.quarterbore.com/images/555th-flatbend-10.jpg

http://www.quarterbore.com/images/555th-flatbend-11.jpg

http://www.quarterbore.com/images/555th-flatbend-12.jpg

http://www.quarterbore.com/images/555th-flatbend-13.jpg

http://www.quarterbore.com/images/555th-flatbend-14.jpg

http://www.quarterbore.com/images/555th-flatbend-15.jpg

http://www.quarterbore.com/images/555th-flatbend-16.jpg

http://www.quarterbore.com/images/555th-flatbend-17.jpg

NOTE: I used a Ball Peen hammer to fold the tops of the rail over. A good heavy hammer with a solid but even blow working from one end to the other produced a nice flat surface...

http://www.quarterbore.com/images/555th-flatbend-18.jpg

http://www.quarterbore.com/images/555th-flatbend-19.jpg

http://www.quarterbore.com/images/555th-flatbend-20.jpg

http://www.quarterbore.com/images/555th-flatbend-21.jpg

http://www.quarterbore.com/images/555th-flatbend-22.jpg

http://www.quarterbore.com/images/555th-flatbend-23.jpg

http://www.quarterbore.com/images/555th-flatbend-24.jpg

http://www.quarterbore.com/images/555th-flatbend-25.jpg

http://www.quarterbore.com/images/555th-flatbend-26.jpg

http://www.quarterbore.com/images/555th-flatbend-27.jpg

http://www.quarterbore.com/images/555th-flatbend-28.jpg

[Quarterbore]

Note, I am renting my flat jig out at least for now as there seem to be quite a few guys that want to bend a couple flats but don't wish to spend the money for their own jig. If you might be interested you can see the details and sign up in this thread:

http://www.quarterbore.net/forums/showthread.php?t=306

[bulldog1967]

Looks Nice! :D

[Cumberland]

I just finished with the jig. It worked great. I used the tapco flats and centered them by using the top edge of the front and rear trunnion holes.
Measuring from the edge of the plate which attaches the flat to the jig. I got 1.003 inches in the front and 1.400 inches in the rear. That is from the edge of the plate to the outside edge of what will be the top of the trunnion holes. I had a couple of questions and Ken was just a phone call away.
Thanks again.

[gcollector2002]

QB

Did you buy a DPHM (or soething like that) bending jig on another site?

If so lets get that bending party going

Thanks

gcollector2002

[Quarterbore]

QB

Did you buy a DPHM (or soething like that) bending jig on another site?

If so lets get that bending party going

Thanks

gcollector2002

Now, spying on me on other sites isn't nice :wink:

Yes, I have purchased two new jigs... One is another 555th jig as shown above and the second is a DPH jig. I am going to modify the new 555th jig to add the alignment pins (making it essentually like the DPH unit) and then it will get put into the rotation while I do the same with the 555th jig that is making the rounds at the moment.

If the DPH jig does offer something that the 555th jigs don't I will put the DPH jig in circulation....

My problem is that I have not received either of my two new jigs yet t test them out... Yes, I am still planning to host a build party but I have had a busy couple weeks to months at work plus a bunch of my websites had to be moved.... and to be honest I am trying to move these forums as well...

More on the move here http://quarterbore.net/forums/showthread.php?t=75 -- YEA That's Quarterbore.NET

When we do have a build party I may need to request somone to host us as my neighborhood and lack of space may cause us problems in larger groups... With three jigs and some dedication a build party could be quite an event!

[gcollector2002]

quaterbore

I wasn't spying as much as I want to buy my own jig and used would be cheaper.
how much space do we need. I have a basement full of tools (mostly wood tools).

I was thinking of buying a DPH jig. does it have these alignment pins? I actually thought the 555th jig was the DPH jig.

My AMD65 kit showed and I have two flats. lets do the party.

gcollector2002

[Quarterbore]

The tools that are needed are portable... The Press is the largest tool and I can carry mine around with little effort. Otherwise the jigs (flat and rivet), flats, rivets, headspace gauges, dremmel tools, files, and barrel press jig is pretty much all you need... besides the time and space...

Ken

[gcollector2002]

QB

There is a gun show:

King of Prussia Pennsylvania: Valley Forge Gun Show - Valley Forge Convention Center - Jun 18-19 2005 610-975-0877

Are you going?

Thomas

[Quarterbore]

Honestly, I would like to but that is way too far into the future for me to say if I can go or not...