Converting a HFC L85 to AEG

[Pendra]

This project is partial because I still have 1 small issue to be solved, but apart that it should be OK.

I tried to make it as straight forward as possible and I'm also open for any further suggestion. By the way, the result is FULL AUTO ONLY, no semi auto! So here it goes:

The components:

A HFC L85A1 springer. I think it is a pretty sturdy gun with 2-3 mm thick plastic body and metal outer barrel. ($50)

A stock Version 6 (P90) gearbox from www.airsoft-armory.com (a HK retailer). ($100)

A PDI 120% spring. Just a little more power. ($15)

A hole-less TM cylinder (left after my M16VN upgrade). ($10)

A 509mm TM barrel (left after my M16VN upgrade). ($25)

A CA M16A2 metal hop-up unit and rubber from www.airsoft-armory.com again. ($25)

A M16VN nozzle which is not long enough for the M16A2 hop up unit (I think). (12$)

A large (called TAMYA I think) connector as the gearbox comes with a small connector.

Wires, saw, screw drivers, knifes, a round rasp, a smaller flat rasp, sandpaper, a pair of pliers, some narrow screws longer than 30-35 mm+corresponding mothers, and a thick sheet of cartboard paper (arond 3 mm).

Totals around $240 and may took 1 whole day or 2.

 

First I made it to accept standard TM M16 mags. For this you have to remove around 2mm plastic from each side of the mag well. I used a rasp and a big knife to crave layers of plastic away. Actually you can see easily the amount of plastic to be removed since that part is deliberately made narrower by HFC. It took a few hours and I got really tired, but at the end the mag slided in and out without much problem. The metal mag holder is perfectly aligned and holds the TM magazine firmly.

 

Next thing was mod the gearbox. You have to remove the trigger part and the cut off lever outright. Then I disassembled the gearbox itself.

To make it work you have to swap the cylinder head's orinetation. However if you do this, there would be no place for the tappet plate. So I took the saw and cut the whole part that is marked with red. This is not hard, the plastic is rather soft, and you can keep to the green part. At the end I used the knife and the sandpaper to have the cutted red part totally smooth and level with the original. If you don't do this, then the tappet place would be unable to go back all the way. Install the hole- less cylinder and it is good.

 

Now it won't fit the gearbox. To fix this you gotta use the round rasp. Remove everything from the gearbox and start to rasp the hole at the end. Don't worry, the GB's metal is not too hard. I did this in steps. Removed some mm-s then put the head and nozzle back and checked if it was good. After the nozzle moved just fine, then I used the hop-up unit to see the amount of metal that should be removed. The end of the hop-up unit has to go into the gearbox so I put the hop unit to the GB and marked the sides. You have to make sure you rasp just enough. If you don't rasp enough then the nozzle will hard time to slide in and out. I think rasping a little bit more would not hurt, but don't go too far. After some trials you will see the point when the hole is right.

 

The tappet plate would be a thougher cookie. I have to warn you, that this is a critical part that ruins the tappet plate forever. Also if you mess up (cut too much) then you have to get a new one! So I put the modified head into the modified gearbox. I also the nozzle to its place. Then checked how much do I have to cut from the tappet plate. Originally I cut 9-10 mm down starting from the very top of the U shape (I will call U shape the part that holds the nozzle). Make sure that it is still goes higher then the middle of the nozzle. Then I used the knife to carve a new U shape to the plate. Actually I think you can use the round rasp to an extent and then you don't have to carve that much. See the pic what I did. If you can't carve perfectly circular (I couldn't) it is not a big problem. The most important are the sides and the bottom. Those parts are straight. If the sides and the bottom fit good then it will hold nozzle firmly. Again this is trial and error but make sure you don't crave too much. Crave a little 3 times then crave 1 big! If you carve too much then you are finished, you gotta get a new tappet plate and start all over. Patience! I don't know about gluing the nozzle to the modifed plate. I didn't use glue.

 

The gearbox almost ready! You need to make it as narrow as possible. You have to rasp or cut down small parts that originally hold the wires (2 L shaped thing at the side of the motor) You may have to cut the screw hole circled with green. Otherwise the hop-up will not fit. Actually I cut a part of the hop-up, but I think it is easier just to remove that screw-hole. The plate on the top of the gearbox and the other screws will hold the GB together.

 

Assemble the hop-up with the barrel. That should be straight forward. After that I fixed the hup-up unit. I used a magazine to determine the exact spot for the hop-up. Use the body part that has the mag holder. It fixes the mag while you tinker with the hop. So put in the mag, and determine the place for the hup-up. If it feeds then it is good . In this process you have to remove or cut a screw holder from the plastic body. Fixing the hop-up into its place was a bit tricky. After some trials the following method worked best. First I put a long screw through the body exactly in front of the pin (the thing on the upper part of the unit, where you have to put the small spring) on the hop up unit. A mother at the other side and it holds the gun together way better than the original plastic screwholes. Also this will fix the hop-up. So I got a sheet of thick, strong cartbord. I Measured calculated and cutted and I ended up with the exact shape in the pic. Since I'm not good in cutting perfectly circular things I got a small screwdriver and hammered it through the paper. It looks more like a 10-12 sided polygon, but still works. The important parts are the "wings" on the left and the right side. That has to be precise. At the end check where the pin goes and put a little hole there (I used a small X headed screwdriver). Since the size of the cartboard plate is exact, the hop-up will not go up and down or left and right. The screw holds it so it won't move forward. The wings on the left and the right will make sure it won't rotate. The GB will push it will not go backward. Finally because you used a mag to determine the location the mags will fit all right.

 

Last part is to fix the gearbox. This is simply painfull. You have to cut most of the screw holes from the end of the plastic body (that means you will be unable to use the springer gearbox any more). But most importantly you got to cut the bottom part of the gun. I cut a 95 mm long part starting around 20 mm after the mag well ends. The other way would be to cut the gearbox but didn't want to do it. That part protects the bottom gear. If you remove it that gear will still stick out of the gun a little. I just hate to think what would happen if you accidentally touched that gear while fireing. I think you don't have to cut 95 mm. You will see how long part should be removed. You have to keep in mind that the hop-up unit has to slide into the gearbox a bit. Also the nozzle from gearbox has to be aligned horizontally and vertically to the hop-up. I found that you have to put 1,5 mm thick spacing to both sides of the top part of the GB (where the cylinder and the piston is). I took the cartboard again, cut long, around 10 mm wide stripes sliced them to half (remember my cartboard is 3 mm thick that meas I had 2 x 1.5 mm stripes) and duck taped them to the GB. At the back part, I also put a piece from the cutted plastic body onto the top of the GB. You don't have to put that onto the top of it on the front part, since there is the little thing that is used to screw the the SUSAT into. So you made sure it will not move to the left or to the right and the end part will not move upward. To make sure it will not move back and forth I used a screw again that went through the marked spot. If you did this right then the GB will surely not move downward or backward. On the other hand this screw is not 100% necessary since the body itself holds the GB pretty tightly. And now the ugliest part: The Motor is too wide for the body. In its normal form you would be unabe to tighten the screws. As I think I should not chop parts of the motor away I had to cut the body. Since I run out of ideas here I cut 2 windows into the body. It doesn't look soo nice but anyway. If anyone has a better idea to rasp away 1.5 mm of plastic from the 2 mm in a 55 x 20 mm area on both sides of the body then don't hold it to yoursef! I thought maybe a small sandpaper piece at the end of a drilling machine would do the trick, but since I'm not familiar with drilling machines I don't know. So I cut!

 

Finally about the fireing. In the HFC version the safety switch and the trigger is made of painted metal. I used that as an advantage. The safety switch is encapsulated into a plastic thing. You need to take the plastic apart. Remove the paint from the switch where the trigger would hit it. Also remove the paint from the back side. Cut a hole into the top part of the plastic thing so a wire can go in. Lay down the front part of the thing, put in an amount of wire, then add the safety switch, then the back part of the thing and push it together. If there is no way to push it together because of the wire then cut a bigger hole and stuff in less wire. Make sure thou that it holds thight enough that the wire will not slide out. The body is made in a way that it will hold the plastic thing together on both sides. I used a thicker wire, but if you decide to use a narrow one, then you may consider to circle it around the metal safety switch a few times, just to make sure. The other wire will go to the trigger. I removed the paint from the top part. Actually remove the paint from everywhere where wire hits the trigger or the safety switch and where the trigger hits the safety switch. Otherwise the paint will act as an insulation thus no electric circuit. So get the other wire and circle it around the top part of the trigger. You can put it anywhere as long as it doesn't fall down.

 

You have to cut down the original fire switch on ther GB and connect the wires that were cut. Now the small connector works without the switch. if you plug a battery to the connector then it would fire endlessy. Now you have to use the large connector. 1 thing before proceeding: MAKE SURE THE RIGHT WIRE GOES TO THE RIGHT PART OF THE CONNECTOR else the fuse or the motor will blow. I have a simple method for this: On the connectors there is a round part and a squared part. The wire from the round part goes to the squared part and the wire from the squared part goes to the round part. Squared=>Squared or Round=>Round= problem! I got a wire that was thich enough to firmly fit into the small connector. So I pushed 1 wire into the round part on the Small connector and connected it into the wire which comes from the squared part of the Large connector. Then connected the wire which comes from the round part of the Large connector to the trigger wire. Finally I plugged the safety switch wire into the suqared part of the Small connector.

Finished! You should be a happy owner of an L85 AEG 8)

 

Some additional things: The most crucial screw is the one at the bottom end of the body. That HAS to hold. If it is not good then you have to put a screw through the body there! Mine holds so far.

The SUSAT is so-so. You may get someone to make you a flat rail and fix it with the given screws. Also I made the original SUSAT more useable with a piece of duck tape. You need to cut 2 small stripes 1 long and 1 short. First stick the long stripe horizontally to the center of the back lens. You don't have to be dead accurate since you can set the susat up and down. As you guessed the other is the vertical part. You have to be really carefull with this one! While in use you will focus on things that are far away therefore these lines will be pretty blury. However if you align the top _|_ with the bottom | then you will see a blury + and you will hit around the center. A G&G replica sight is way more accuarte, of course .

Right now I tape the battery to the side of the gun. I just don't bother to cut and carve the foregrip, rip the battery apart and wire the cells up.

The barrel does not fit perfectly to the outer barrel, so I circled some layers of tape to the end part of the inner barrel to fill the space.

 

The weird part is that it snaps together like it was ment to be. If TM made an Academy style body and make the back part 10 mm higher then the V6 would fit perfectly. The only thing that they would have to engineer is a shorther tappet plate. The semi fire switch could be solved by using SIG550-551 style burst electronics fixed to 1 shot.

 

PS.: Excuse my grammar and spelling

[Lance Jackass]

DUDE great guide mate. +1

[Megalomaniac]

Very cool and extensive guide. Should help anyone wanting to make an L85, if you got more pictures and less illustrations It would be a bigger and better help.

[Pendra]

I will do some pics as soon as I can get hold of a digital camera. Meanwhile it turned out that the piston was to be blamed for the inconsistent power I experienced (the piston did not push it through the sealing rubber). I made a VERY LONG piston using the one from the P90 gearbox and super gluing a piece of a pen to its end. I guess the standard M16A2 piston is long enough so it should work but I made my piston cos I didn't want to wait a week for a geniue piece. Anyway the gun works great ! Now I can hit a helmet 4 out of 5 from around 25 m with 0 hop-up.

As I had fun while building it I think I will do an other gun (for sale since my monetary funds are not unlimited ) as soon as I find another V6. I want to use an Academy because its inside is supposed to be a few mm wider so I don't have to cut the "Windows" onto the sides.

If someone is interested in that L85 or have a WORKING V6 for sale PM me! My guess that it will be around 500$+shipping payable only when I have it ready and tested (I'm not AirsoftClub ). The price is made up of these stuff:Academy L85 110$, HOP-UP 25$, Systema Barrel 25$, cylinder+nozzle 25$, gearbox 100$, around 160$ shipping from HK to Hungary+VAT, and hopefully 100$ for my custom work.

[Clastyclay]

Nice work mate.

 

But I have a few probs by reading the tutorial.

I'm german and the technical stuff confuse me a bit.

 

If you have a digicam ... could you snap every step that you made?

I know ... many pics ... but I will give you webspace for it

And you will get a big smack from me.

Just think about it

[Pendra]

A few pix as promised

http://invitel.hu/corsair1/L85P.ZIP

It is actually faster and easier to take apart and put back together than the M16. I will take it to a day long skirmish and will test it in battle also I will try to chrono it there.

[Clastyclay]

Ahhh great.

Nice work.

Thx.

[Hissing_Sid]

Academy AEG all the way IMO.

 

Least it is designed to fit AEG internals including stuff like batteries.

 

[edit]

Saw pic's. Sorry but what an abortion. Insulation tape is not the item of choice for holding gearboxes together.

 

Why would anybody want to do all that rather than just bunging a new spring and a couple of other bits into an Academy AEG?

[Fanatic]

Nice work mate, never heard of someone converting a springer to an aeg The inside looks very adventuresome

[Pendra]

The insulation tape is there to act as a spacer or hold the spacers in position. Screws hold the GB together. The reason for this? Well because it is V6. It could fire at and over 400 FPS without the slightest problem. You can easily get parts for it (should I mention FAMAS Nozzle), there is an FTK for it etc. Better yet if you have a M16A2 or equal, since then you can swap parts and use lefovers from tuning. I'm sure academy would be better but the academy would cost me 180$ with shipping and this HFC was lying around for free. The bottom part of the body has to be cut in any way. I saw the same thing on the royalmarines pix. Right now the whole stuff costed me only the gearbox and a hop-up unit since all other parts were leftovers. 160$ with shipping is not bad for an AEG I guess.

[Hissing_Sid]

160$ with shipping is not bad for an AEG I guess.

<{POST_SNAPBACK}>

Erm, whatever floats your boat but your own cost breakdown says it costs you $240. An Academy AEG costs £100 and comes with stuff like a purpose-built battery compartment and a gearbox which fits inside the shell.

 

The HFC springer L85 is also about £70 in the Uk rather than the $30 you reckon it costs in the UK.

 

Up to you but I'd rather have a gun where the internal parts stay inside it.

 

Have you figured out how to make it fire in semi yet?

[Clastyclay]

http://royalmarines.mine.nu/engineer.php

 

The Academy Sa80 has a low quality material.

Don't go with Academy.

[Pendra]

Trust me I calculated all possibilities.

1. Get a A L85 for 110+70$ despite all the horror stories I've read thoroug the web and from my freinds (one was about a shattered gearbox). It will shoot 220 FPS, no hop, and may get killed within a few thousand shots. The total cost is 180$

2. Tune it up. Add a stronger spring and a TM motor and a M16 hop-up and an M16 barrel. That is 180 +15 spring +35 motor and use the leftover. With that I may reach the M100 but I risk breaking the GB itself. Also the EG560 is not swappable with the EG700. I'm at 230$ (about the price of a stock FAMAS) and I have a gun which has the same power but less reliable than a FAMAS.

3. Get a FAMAS for 170$+40$ and swap the whole thing. Trusty TM quality but still lacks the power the upgradeability and the available parts. That would go somewhere around 380$. Add to the thing that it is just not that fun to fight against M120 with a M100 gun.

4. Get a full size L85 and not necesseraly Academy. You can get a HFC at around 100$ (Airsoft128 listed it for 40$) no matter if you order or get it from a shop (mine was a gift so costed 0$ ). I never handed an Academy L85 but this HFC one is pretty good quality with metal parts (including the full outer barrel) and very thick and rigid plastic shell. Using a V6 costed 100+30$. For this price I got one of the most advanced gearbox instead of an almost antiquated one. It is TM quality. I got the chance to upgrade its power it to my liking with a good selection of quality parts. I have interchangeable parts (including the motor). And the price for this is a cut at the bottom 2 cuts at the side and a battery compartment.

1st version 180$, Underpowered, Unreliable, little replacement part support, intact body, Semi Fire

2nd version 230$, max M100 power, improved reliability, little replacement part support, intact body, Semi Fire

3rd version 380$, max M100 power, TM quality, little replacement part support, intact body, Auto only

4th version 230$, max M130 power, TM quality, wide variety of part available, Slightly modified body, Auto only. Add +80$ for less cuts and a battery compartment (Academy).

(the price above does not include the hop-up and the barrel or any other part that may be needed for example cylinder and nozzle)

From these options ppl can chose which are the important factors. For me it is Price, Reliability, Power, Authentic Looks. Hey most of the time I see the barrel and the top of the gun (which are intact). If I went with price looks power reliability then the 2. version would still be tied with the 4.

Full auto and I'm not planning any semi auto thing, I think the semi auto is about as important as having a side arm while you have the most reliable and perfectly CQB AEG with a 2000 auto winding mag in your hand.

[Hissing_Sid]

Like I said, whatever floats your boat.

 

I dunno how you can say you prefer the "authencicity" of a HFC based gun when it's got lumps of gearbox hanging out of it.

[Clastyclay]

Compare his custom work and the HK one ... it looks similar(except the motor window and the bottom cut)

The cut at the bottom of the body can be solve, if he cut out a bit from the gearbox(then you can see one of the gears)

The royal marines used the same method.

 

But why did you cut out a window for the motor? It should fit in the shell very well.

[Pendra]

Well I had hard time fitting the shell together so I chose the easy way. Rather than removing 70% of the bottom part plastic I just took a rough measure and cut. I was in a hurry and I was more interested in seeing the internals in work than to pay more attention to trivial details like the shell . Now that I know how to make the intenals work I can pay more attention to the outer side. Since than I made a computer modell so I can see more accurate measurement and things that is hard to notice in another way. Consider this gun a beta version.

About the bottom of the gearbox, well I don't want to remove it. The running bottom gear would very very dangerous without the cover. So I decided that I rather have 10 mm metal sticking out at the bottom than having serious deep cuts on my hand. Black insulation tape or black paint would do the trick for me.

The field test today went flawless. It chronoed at around 280 FPS and I had no problem whatsoever with the cycling. The only problem was the hop-up. It seems that the rubber is not totally centered so the bullets went a little to the right, but it wasn't too serious.

Finally this is not the only way to get a L85 AEG. That is just one option out of many.

[Clastyclay]

Don't worry about the bottom gear(if you cut the bottom)

Look at the pictures of the HK Royal Marines.

 

 

It works

[Pendra]

I think the whole thing sits higher in their version. They have very little space between the top of the shell and the GB. In my version the position of the GB is determined by the length of the hop-up feeder. I think they extended the feeder so they could lift the GB higher. In their pic, the bottom left screwhole is just over the plastic body while on my pic that screwhole is in the body line.

[Pendra]

I disassembled the gun and I have some more findings. I don't know what the RoyalMarines did, but even if I rise it all the way up the bottom gear is still in line with the outer side of the shell.

I also made a battery compartment. I just rigged up the battery to the forward grip. I had to do some cutting that took about 30 mins but it fits great. I sliced a 8.4V large battery into 2 piece. One has 4 cells and the connector, the other has 3 cells. I connected them with 2 pieces of wire. That is all. The batteries are still in the shrink wrap, and they can be used in other AEGs.

[Pendra]

Final thoughts

After measuring very carefully I found the following:

The outside of the lower part is 30 mm wide. A wall is around 2.5 mm. The max width of the motor is 28 mm so it can positively fit into the shell, you just have to remove 1.5 mm from both sides. The gearbox will still stick out at the bottom. I would either use another HFC L85 bottom to extend the height or make a simple piece of metal to cover the GB. A 2nd HFC body is on the way to improve the looks . So everyone will be happy at the end!

[Pendra]

Last version:

Battery in the foregrip. The safety switch is not in its place, cos I need some more wire to add. Also the green triangular thingy at the bottom end is missing because I lost it somewhere and I'm not happy about it. I glued the spacers to the inside of the body so no need to tape it to the gearbox any more. I will add 1 more screw go through behind the mag well to hold that part together as the original screw hole there got wasted.

[Clastyclay]

Man ... that's a good job(except the motor window)

But the bottom is still looking ugly

 

I will try to get more informations, that you don't have to cut the bottom.

It is possible.

 

Why have you cut the bottom of the butt plate?

 

Nevertheless ... great work!

[Pendra]

I didn't cut the but plate, that thing at the bottom just fell off on its own accord. And I lost it during the process of the assembly. I still think that the best way would be to use a 2. body and some glue to add the missing height to the body. Raising the internals would make the whole thing more complicated and less reliable. I've read at an other forum (UKAN I think), that a guy went though a very similar process, but had serious and persistent feeding problems and he just gave up at the end.

[Hissing_Sid]

Doesn't look too bad in the end. As long as it works OK and is reliable I bet it'll attract interest at skirmish sites.

 

One thing: How much work did you have to do on the mag-well to get M16 mags to fit?

Are the HFC mags just a tiny bit smaller and more rounded, like Academy ones?

[Pendra]

About 1-1.5 mm on each and every side. The most annoying is the _||_ part at the back side of the mag. It is fairly easy to remove big pieces of plastic on the left and right sides. The complicated parts are the front and the back side as they are small and hard to hold the body and the knife firmly.