H&K G11K2 as CO2-powered GBB

[marvk]

Thanks for your creepy comment I will see it as a positive one and just close the door behind me when I get back to work

[Murdoc]

I would quite literally murder for a workshop like yours.

Same here...

 

How durable are the router bits if you use the on light (copper, alu) metall only? I mean how soon do they loose their sharpness?

 

An if using them on steel? Do you think that they should be cooled by oil etc. (I mean if usin on steel)?

 

Thanx!

[marvk]

That is not an easy question to answer. as you can see the, the surfaces I get differ quite a bit. the 12mm milling cutter I am using the mill larger surfaces has seen quite some action but the results I get vary from the kind of material I am cutting. with the "soft" alu like AlMg3 its like butter but with the 7075 everyone is so crazy about it is a p.i.t.a.. I can only go for very shallow cutting depths (0,25 to 0,5 mm max) on my machine. everything else does not sound healthy. for steel it is even worse, very very shallow cutting depths and yes cooling is required, I use WD 40 most of the time, because thats the only thing I got.

 

Since I don't really know what I'm doing with these machines, I can't really tell you if the tools are still sharp enough. I did not learn to use them in school are anything, I just bought them and then trial and error. So far , not many errors occured but I am very careful what I am doing on these rather small machines (compared to "industrial" equipment).

 

I rarely use steel. simply because I don't think the extra strength provided over a good aluminium (5xxx or 6xxx is fine for me and my machines, 7075 not so much) is not really needed in the airsoft world. thats my opinion, we will see if I have to change it when there is a functioning G11 some day and wear and tear becomes an issue.

[Murdoc]

You're right! On "modern" rifles, pistols you don't need steel. They are powder coated, or anodised. And partly alu too... And partly stainless steel material.

 

Only problem is if you have a full steel airsoft AK, and you want to make something for it...

[marvk]

That certainly is a Problem then. But if you really want to work with steel on machines not only occasionally, you would have to go for a bigger, more rigid one. What is it, that you want to do to your ak?

Before I got my machines and was active here, I tried building a WA2000 with an 1950's drill press and some hand tools, including steel parts. It is possible but it is not pretty and did not really ever function due to gas leaking issues.

I am really hoping for the G11 to work in the end because there is already a lot of time and money invested.

[Stuey]

I think we're all hoping this is a success dude! Super cool project.

[marvk]

Hey guys,

 

quick update with today's work!

 

fitted some o-rings for sealing purposes on the barrel shroud and the piston:

 

Turning a tension spring into a pressure spring in order to serve as the recoil spring. I did it this because my local hardware store did not have an adequately sized pressure spring and I have run out of thick spring steel wire.

 

the spring:

 

stretching and heating with the torch, then quenching with water:

 

again stretching, heating and quenching to the final length:

 

using the torch and gravity to straighten it (after cutting of the ends with the bolt cutter):

 

et voilà, the spring fitted:

[paranoiddroid]

If that bolt and trigger system works as designed you could make a fortune! I can think of at least 3 builds of mine.it would be perfect for.

[marvk]

Update!

 

starting with the recoil spring. the one I made by transforming a tension spring into a compression spring turned out to be too weak.

I bought some spring steel wire and wound a new one on the lathe, trying 1,5 mm and 2,0 mm diameter wire.

I still have a 2,5 mm lying around but so far the 2,0 mm spring seems to be strong enough.

 

in the following pictures you can see 1. winding of the 2,0mm wire, 2. winding of the 1,5mm wire and 3. the finished 2,0mm spring with

around 8mm lead / pitch and an OD of 27mm

 

 

And as the final picture for today: a crappy lighting late at night photo of the whole "gas"-assembly disassembled:

 

 

As you can see, there is no madbull CO2 charger in the picture. For testing and building purposes I replaced it with an adapter to attach

the gun to my compressor.

 

I hope to make some progress the next weekend and explain some more details about the fixation of the (inner) barrel and correct order of movement

for the, obviously, moving parts with which I still have some problems.

[Maus]

Awesome work. Great home build. Not to hijack, however here is my effort from back in 2010. I modeled the gun in SolidWorks and designed a dual feed system. The goal was to use air or a lipo with a 3 shot burst mech to get a realistic rate of fire. The hopper has a 2K round capacity, or one can use the magazines that hold 200 rounds each. The model above was the first non firing prototype before redesigning everything to look and function more like the real deal. At that point large SLA models were and still are pretty cost prohibitive, so I never made it past the first prototype you see above. If you need help with the models let me know. I think I managed to get it to 90% accurate just from photos and all the technical data HK sent me back in the mid 90's.

[marvk]

Hi Maus, thank you for sharing! Your model looks awesome, Mine probably will not be as accurate. I would be very much interested in technical data from hk. Did you just write to them or how did you get in contact with them?

 

I will go to my Workshop and do a little work but unfortunately my time is very limited atm.

 

Do you still have the cad files? I would love to compare measurements, just to see how good scaling pictures works. Just from looking at your model on my phone I think that your rear section looks longer than mine. I mean, your G11s rear section;)

 

Cheers marv

[Maus]

Thank you for the compliments. I tried to get the model as accurate as possible. I was going to make the first one as a AEG and use the modular GB for a M-60. That would allow for the dual feed system (both gravity) to work well with off the shelf parts. The second one (assume the first one worked) would have been a gas system. Unfortunately I never finished the project so I will live vicariously thorugh your work.

 

I have the CAD files but they are solidworks .prt files. So I am not sure if your software will be able to import them. It may be possible to export them as some other format. Let me know what the native format of what you are using is and I can send them to you. Even 4 years on now, my cad files are a work in progress. I found out a few months ago there is a depression for the operators finger under the winding mechanism, so I need to add that. The night vision scope isn't finished either. I still need to make all the information plates and tags. The gun itself has about 40 parts, excluding internals from a donor gun. I have files for each individual part so if you have any questions or need files just ask.

 

I called HK of America directly. This would have been in the late 90's after field trials concluded. They sent me a nice press packet and that is where I got my overall dimensions from. IIRC the stock is longer than the forend by about an inch. I think that the stock of mine is 12.5" long. I can confirm at work on Monday. Below are the overall dimensions of the real deal from my information.

 

Length overall - 750mm/29.53"

Height - 295mm/11.61"

Width - 74mm/2.92"

 

In the press packet there is a nice black and white line drawing and that is what I used to sketch from. I imported the Jpeg into SolidWorks and sketched directly on top of it after scaling it to the dimensions above. The original photo (as you can see from my physical prototype) is a weird combination of the K2 front end and the body and rear stock of the K1. In my redesign, I did the entire thing as the K2, as I had a good base to build from. I think my finished overall length of the model is 30.5", so that means I added .5" to the front and rear since the other version didn't "feel" right. I had to make a few educated guesses as to the width as well. Mainly the angle from the center of the main body to the rear of the forend where the magazines enters the main body. I didn't want the forend to be too thin, and I struggled with getting this as close as possible.

 

FWIW, I started modeling up the single magazine K1 forend as well. I was about halfway finished when I stopped. I really figured some Chinese company was going to release a G11 based on the success of whatever COD game the G11 debuted in at that time. So I didn't want to spend all the money (more than 2K) having one made only to have a factory produced one released and be a lot less expensive.

[marvk]

I used sketch up for this project but now have autocad inventor for all the things to hopefully follow I think that Autocad can import the solidworks .prt files, so that should not be a problem.

 

let's switch to personal messages in order to arrange the data exchange. maybe I have some pictures or literature that is of interest to you. I recently found the german manual hk prepared for the german armed forces.

 

yours is probably a lot more accurate than mine, i just used pictures to scale from and the width of several parts are just good guesses, I'd love the compare them with yours.

 

I do not think that there will be a factory produced G11 any time soon. In my opinion it is to far away from the M4s, AKs and G36s everyone is using.

 

Anyway, I did get some work done. In the picture underneath you can see the disconnector made from a solid block of 7075 aluminum. In the 3D model it is the part in light green right under the big red cylinder.

 

 

Cheers Marv

[marvk]

Update!

 

continued on auto disconnector and hammer, already put the axle in them. Also on the picture the three parts of the trigger.

 

 

On the left:

 

at the top the upper part of the trigger

 the part in the middle the middle section of the trigger

at the bottom, the lower section of the trigger. the part you actually "touch"

 

on the right the auto disconnect i already posted in the last post and the hammer underneath it.

 

marv

[Murdoc]

I can't wait to see this workin'...

 

I'm ordering a combined lathe/milling mashine at the moment...

[paranoiddroid]

Hypothetically if and when you get the internals running would you consider producing one for others?

[bankz5152]

Id deffinatley strongly consider buying one if so.

 

On my phone my spelling will suck

[marvk]

Hey Guys,

 

unfortunately I have to disappoint you regarding making more than one of these things. Due to rather strict regulations regarding "weapons" where I live I can not ship airsoft guns. Furthermore, this one takes so much time, I doubt I will have enough time to do a lot more than one gun a year once I have finished studying. So, no guns custom built by me for you guys :-(

 

Anyway, mode some progress over the weekend. I do not have a lot of pictures but the following show the transformation of the still rough-cut lower section of the hammer to the round nub required. Later on this nub will be partially filed of too, in order to work with the trigger. The nub has a diameter of 4 millimetres.

 

 

 

[famidesu]

This is amazing! Anything CNC made makes me drool. I have been trying

to figure out where to order these kinds of hobby machines, but I haven't

quite got my head around it sadly. If you did purchase your stuff overseas

from like ebay or similar, feel free to give me a pm or something!

 

Again, this is amazing. 

[marvk]

Thanks famidesu! Unfortunately, I Do not have a CNC machine, unless you count my brain as a Computer and my hands as step Motors overseas looking from what side of which sea? I did purchase my lathe over eBay and the milling machine from the same Shop directly. Their webpage is: www.paulimot.de and it is German. As far as I know it is an upgraded version of sieg machines. You should be able to find this company via the search engine of your preference! They all come from China for this kind of money but paulimot fit a German or Austrian motor and frequency converter in order to get rid of the DC motor. So far I am very happy with them. You always have to consider a reasonable amount of money that has to be spent for accessories on top of the machine cost. That is probably half the money the machine will cost you if you want to do some fancy stuff.

[Pompe]

Sieg machines in Sweden http://www.smaskin.se/ tho stuff like that can many times be cheaper to order from for example Germany :-)

[DEVILHUNTER]

Marvk, your milling machine is a copy of the BF20. There are a lot of copies of factories that make or rebrand it with small diferences. Sieg makes other models.

 

It's pretty simple to convert to CNC, even installing ballscrews, and not too expensive. In the USA is usually called g0704.

 

CNC conversion: https://www.youtube.com/watch?v=0sI7WFSaucg

 

Hoss page, lots of info: http://www.g0704.com/ (check also his post on CNC zone)

 

I'm saving for it's bigger brother, the BF30, twice the weight, but as you pretty well said, the cost of tooling is even more than the machine itself.

[marvk]

You are right, DEVILHUNTER. I mixed it up in my mind. I was looking at Sieg machines too when I decided which one to buy.

 

Upgrading to CNC is a very nice option, we will see if the first job next year will make that possible or impossible

 

I probably will not have the chance to go to the workshop before the weekend. That means there will be an update on Sunday as usual but probably only a minor one.

 

thanks for all your comments, I was close to giving this one up but now knowing that there are some eagerly awaiting the G11 to be working I am more determined than before to make it happen

 

cheers marv

[Imperator]

 

thanks for all your comments, I was close to giving this one up but now knowing that there are some eagerly awaiting the G11 to be working I am more determined than before to make it happen

 

cheers marv

marvk, don't you dare giving up on this one! Our lives depend on it, like a junkie on his daily fix!

 

There is, seriously, a great number of people here that need to see this finished and working! As far as I'm concerned, you'll be my new hero! XD

[paranoiddroid]

What I meant was the internal mechanism being sold rather than a full gun marvk as it is shaping up as an amazing design and piece of engineering that would be perfect for a few of my designs.