CETME Wood Furniture Modification Guide

[James Kelly]

CETME Furniture Modification Guide

 

In this guide, I will be walking you through the steps necessary to fit a set of wooden CETME furniture to a G3 of the airsoft variety, as well as providing a few tips and tricks to get the most out of your new setup.

 

Over the course of the modification, we will be going from this:

 

To this:

 

I've been very reluctant to post this, mainly because of the uniqueness that I've enjoyed, being one of the few U.S. players with such an uncommon setup. The reception that I've recieved with this build has been overwhelmingly positive, and I've had a number of people ask me for assistance with similar projects, which has helped me to realize that it's long past time to share my techniques and methods with other players interested in doing the same modification.

 

And so we begin.

 

The first step is to acquire the necessary materials.

 

The two options for G3 compatible wood furniture are the sets designed for the real steel G3 and CETME, both of which require some modification for use with airsoft guns. The G3 furniture is extremely rare at the moment, and a set in good condition, if found, will run you at least $50. However, I have not seen any complete sets for sale in over a year, and their availability in the future is not something that I'll be counting on.

 

In contrast, CETME furniture is available at a number of retailers for approximately $20, up from $10 only a few months ago. CheaperThanDirt is my source for the sets that I use in my builds, the furniture being made by Tapco, and of acceptable quality. Another bonus is that the furniture is commonly sold in sets, which include two stocks in addition to the forearm, which allows you a bit of leniency in the event that you bodge the job on one of the stocks.

 

http://www.cheaperthandirt.com/MGR300-1.html

 

Due to the relative scarcity of G3 furniture, and low cost of the CETME sets, this guide will be meant to cater to those who plan to use the CETME furniture. Additionally, guides for the fitment of G3 kits already exist, an excellent one having been written by a friend on Arnies: "LiquidFlorian", a link to which will be included at the end of this guide for any interested parties.

 

The next required item is the rifle itself. This guide will address fitting the furniture to both the Classic Army and Tokyo Marui G3's, which differ in only minor respects in regards to fitment.

 

In the way of tools and working materials: A drill and drill bits, vice and sandpaper are necessities, as is a Dremel tool with a cutting wheel and sanding drum. A bench grinder, Japanese handsaw and file are recommended, but are not absolutely necessary.

 

I will be covering the fitting and modification of the stock first, moving forward to the forearm later in the guide.

 

the first step is to remove the plastic stock and mounting hardware from the gun, and to disassemble it, breaking it down until you have the endcap sitting by itself, unattached to anything. This piece is the most important part of the stock for our purposes. Take the rest of the stock and place it to the side, out of the way. We have no more use for this.

 

This photo shows the unmodified CETME stock and the mounting cap. As can be seen, when we try to insert the stock into the cap, it will not fit properly: Something is blocking the fit.

 

 

As shown below, the stock cap has a number of protrusions meant to properly secure the plastic stock to the endcap, however, these protrusions are simply an obstacle to fitting the wood stock, as it is shaped differently than the plastic stock. The two options are to remove them entirely, or modify the stock to bypass them. If you choose to remove them, simply grind them down with your Dremel and cutting wheel, and test the fit with the wood stock, removing material from the stock until you achieve a proper fit. As I wish to retain the option of reversing the conversion, we'll be taking the avoidance route.

 

Here you can see the protrusions that are preventing the stock from fitting into the mounting cap.

 

At this point, we need to scribe in a few lines on the front of the stock to show where it will be passing through the rectangular hole in the endcap. The wood outside the scribed rectangle will be removed. Place the cap over the stock and trace the outline with a pencil or marker.

 

 

The next step is to measure the inset depth of the protrusions from the edge of the mounting cap. This depth will be scribed onto the stock. One easy way to do this is to insert the stock into the cap until it hits the obstructing pieces, and to trace a line around the stock. This will be the depth to which you will be making your cuts down the long axis of the stock. You should then make the cuts, going first down the long axis, and then down the short axis, to remove the wood surrounding the rectangle that you have just extruded. If you have a file or sandpaper, use it now to clean up the cuts, making it as smooth and regular as possible. The final product should appear as shown below.

 

Compared to the original: Note how the cut goes only halfway down.

 

From above:

 

The stock should be able to slide right into the endcap and mount flush, without an undue amount of movement.

 

If you've gotten the stock to fit to your satisfaction, the next step is to secure it to the endcap. One questionable benefit of the CETME kit is that it doesn't have the metal screw anchors that the G3 stock does, meaning that it can be attached with simple coarse threaded wood screws. It's a much easier solution, but the long term durability is questionable, However, after a good deal of use with my personal build, I have yet to see any wear or feel any looseness.

 

After getting this far, it would be a shame to have to start over because you've split the stock, so we're going to drill a pair of pilot holes for the screws to follow into the stock. It's worth noting that you need to pick a bit diameter for the holes that's a bit smaller than the diameter of your screws. If you make the hole diameter too wide, then the screws won't have anything to grab onto.

 

Place the stock cap over the wood stock, and use an awl or pencil point to mark where the screw holes pass through the endcap onto the stock itself. An easy way to do this is to simply stick the point of your instrument through the two holes above and below the rectangular opening to make your marks. Then, take your drill with your selected bit and drill the pilot holes, making sure to keep your angle as close to 90 degrees as possible.

 

 

Now that you have your holes, and your stock is cut to fit, you can screw in the endcap. We're starting to get somewhere now.

[James Kelly]

Moving backwards now, we need to attach the buttplate. This part is exceedingly easy. The stock might require a bit of sanding, but for the most part, the buttplate is a drop on fit. The buttplate should have a pair of screw holes in it as well. We're going to drill another set of pilot holes to mount this as well, so make your marks as you did the previous time, select your bit, and drill the next set of holes. You shouldn't need to go much deeper than 1-1.5", shorter screws will hold this piece in just fine.

 

"But wait! I can't fit my battery in the stock anymore! there's no place to put it!"

 

Here we come to the one main shortfall of the CETME furniture. The stock is solid, rather than hollow as with the G3 wood furniture or the plastic stock, and as such, we cannot store a pack in the stock as we could before. There are two ways in which we can surmount this problem.

 

The first is to run the battery externally, either with a sling mounted battery, or with a battery in a battery bag mounted directly to the stock. Both ways will require a small hole to be carved in the buttplate, to run the wiring through. By this point, you should have notices that the CETME stock comes with a hole drilled through the body from front to back, which we will make use of as a means of running the wires though. The hole in the buttplate can be made with a knife, any sort will do. The material is soft enough that you can simply scrape it away until you have a hole big enough for two wires to pass through. The only thing to note at this point is to make sure that you make the hole on the side that will be facing away from your face when you shoulder the rife, as it will keep the wires and battery out of the way.

 

 

 

 

You can either use the wiring that you took from the old plastic stock, or you can make yourself a new wiring extension. I initially used the wiring from the stock gun, but later put together a new set with some better quality wiring and deans connectors. This part is pretty much personal preference, and depends on how much motivation you happen to have at the time, as well as your skill with a soldering iron.

 

The second way is to utilize a custom pack stored in the stock, though this will require a bit more work on your part. The way to do it is to bore out the top hole in the stock with a drill or drill press, as well as drilling the lower hole deeper. You then have to build a battery pack, split down the middle, with as many cells as you can fit in the top tube, and the remainder in the lower tube, connected by a set of wires. It should look like a lopsided nunchuck pack. I have not gone this route, as large type cells will be extremely difficult to fit, and I enjoy the higher discharge rate that they can provide. A LiPo battery is another option, and one that is designed to fit in the buffer tube of an M4 would likely fit without too much difficulty.

 

This choice is dictated by user preference, and whichever way you choose to go about it, give yourself a pat on the back after completing it. If you've done it properly, you've gotten past the hardest part of the project. If you've mucked it up somehow, don't fret too much. You've got a second stock with which to do it properly.

[James Kelly]

We're now going to move forward to the foregrip. This part requires a good deal more trial and error, and is a bit more time consuming, as a tight fit is extremely important for this part. If you remove too much material, your foregrip will wobble, something that will detract significantly from the overall look and feel of your rifle.

 

The first step is to attach the front endpiece to the foregrip. The fit will be exceedingly tight, and will likely require the use of a mallet to force it to seat as far back as is needed. It should be self explanatory as to how far it needs to go, as the foregrip is shaped to accommodate it only to a certain point.

 

We also need to remove some material from the inside of the front cap, as there is not enough space to accommodate the front sight lug inside of it. For this, you need to use the cutting wheel on your Dremel, and by means of some fancy maneuvering, you want to remove the two side mounting prongs, and remove some material from the bottom, to give you something that looks like the piece on the left.

 

This is one of the trial and error portions of the process, in that you need to continually remove material and test the fit to the gun periodically until you get it to fit properly.

 

We need to leave the rear endpiece for a bit, and work on the wooden portion of the foregrip now. If you look at the barrel and the area where it mounts to the receiver, you will notice that the interior of the foregrip is too narrow to fit over it, being hung up on the barrel reinforcement tabs and the horizontal reinforcement panels running immediately below the barrel. We need to remove material from the foregrip to accommodate them, as the structural integrity of the rifle should remain intact.

 

Reinforcement tabs:

 

Because a tight fit of the foregrip is crucial to prevent wobbling, I hand sanded the sides of the foregrip, removing approximately 1mm from each side. This part is trial and error as well. You will need to remove material and constantly test the fit, taking pains not to remove too much.

 

Additionally, to accomodate the prongs of the barrel, it is necessary to remove some material from the lower portion of the foregrip, as well as from the sides. For this, the dremel and sanding drum can be used, as hand sanding is excessively difficult in this area. As always, be careful not to remove too much.

 

Note the modified foregrip compared to the original foregrip, namely the amount of material removed. The rearmost lip was removed, and on the inside of the foregrip, just enough was removed to accommodate the reinforcement tabs.

 

Now, for the final piece of the puzzle.

 

The rear endpiece is designed to mate to the real steel receiver, which is shaped in a way to be able to accept more of the endcap. The airsoft receiver is somewhat different, having tabs on the sides for barrel reinforcement, and as such, we need to remove some material on the rear endpiece to accommodate them.

 

On the left, we can see the original endpiece, and on the right, we can see the modified endpiece.

 

We need to remove material from both the front and the interior, leaving only a band that will wrap around the exterior of the foregrip. This is where the bench grinder and the Dremel tool with the cutting wheel come into play.

 

You can see in the second photo that the rear endpiece has what we could describe as two bumps: one wider bump on the bottom, and a second atop it, somewhat narrower, a lip meant to mount inside the receiver of the real steel CETME. Because our foregrip is too long for the space provided, we need to remove some material from the foregrip, the ideal location being the rear endcap.

 

First we will remove the material from the front, the topmost layer. I used a bench grinder for this, holding the endcap with gloves against the grinding wheel until I had removed the first bump entirely. The Dremel cutting wheel can be used for this as well, so long as the same result is achieved. Test the fit on the foregrip, and reshape it if need be, as the heat can deform it somewhat.

 

The next step is to take your cutting wheel and cut out the inside of the endpiece. It should only be held on by two small pieces at this point, so two quick cuts will do it. I recommend mounting it in the vice while making the cuts, as the vibration from the cutting will more than likely cause you to lose your grip.

 

At this point, you should have a pretty good idea of what needs to be removed. You want the metal to wrap around just enough to reach the top on each side, to create the illusion that it wraps all the way around. Bend it to shape, and if you feel the need, place a few drops of glue on the inside of the band to secure it.

 

At this point, you should have something that looks like this:

 

You can then mount it to the rifle, and secure it with the pin that was used to secure the old foregrip. The front is secured with the pin, and the rear is friction fit with the reciever. So long as you didn't remove too much material, the fit should be tight enough that you don't have any wobble at all.

 

One little trick that you can use to make it a bit more solid is to put a small piece of padding between the foregrip and the receiver tabs. This serves to tighten up the fit, and prevent creaking.

 

Now that you have everything shaped and screwed, all you need to do is stain and seal the wood. The CETME furniture comes unfinished and unsanded, both of which are left up to the user to take care of.

 

At this point, use painters tape to wrap up all the metal parts, and give the wood furniture a thorough sanding with 200 and 400 grit sandpaper. A rubdown with a cloth scrap would be a good finishing touch as well to get some of those last burrs out, as well as to remove some of the dust that has certainly been produced.

 

Now that it's sufficiently smooth, apply your choice of finish. I myself used a base coat of mixed walnut, cherry and red stains, with two coats of shellac applied over it, but the choice of finish is of course left up to you, depending on what appeals to you, as well as what may be available. Allow it time to dry, and give it another buffing with 400 grit sandpaper and a cloth, and you're finished with it.

 

You're done, and you've created something unique and pretty damn beautiful. A battle rifle that can kick butt, take names and look good while doing it.

 

 

Links of Note:

 

LiquidFlorian's G3 guide: http://www.arniesairsoft.co.uk/forums/inde...howtopic=153152

CheaperThanDirt's CETME Furniture: http://www.cheaperthandirt.com/MGR300-1.html

 

I spent a good deal of time on both the modification and guide, and I'd appreciate it immensely if this was not reposted without my permission, be it attributed to me or not.

[Ahab]

Very nicely done, a lot cleaner job than mine. Anyways, a note on the battery, you can bore out the tube that runs through the length of the stock to accept a regular mini style stick battery. I modified a CETME stock to accept a 1500mAh stick based on 2/3A Elite cells.

[liquidflorian]

Very nicely done, a lot cleaner job than mine. Anyways, a note on the battery, you can bore out the tube that runs through the length of the stock to accept a regular mini style stick battery. I modified a CETME stock to accept a 1500mAh stick based on 2/3A Elite cells.

 

I would think a Lipo would be fairly easy to get into a modified stock...

 

 

Great write up James!

[The Crunchy Bunny]

Really Great guide. Makes me want a G3 again.

[Cliffor]

Wow, this pretty much decided what rifle I'm buying next

Thanks a ton for the guide! Though I was wondering, is there enough space in the foregrip to put in a stick or mini battery?

[James Kelly]

Wow, this pretty much decided what rifle I'm buying next

Thanks a ton for the guide! Though I was wondering, is there enough space in the foregrip to put in a stick or mini battery?

 

Nope.

 

Your options for battery storage are:

1. Inside the stock

2. On the stock

3. On a sling

[yuanshi23]

You my friend, are a G3 god...props to you for the amazing modification

 

Just wondering, is it possible to mod the CETME stock to fit a large type 9.6?

[James Kelly]

You my friend, are a G3 god...props to you for the amazing modification

 

Just wondering, is it possible to mod the CETME stock to fit a large type 9.6?

 

Simply put, the stock isn't wide enough for that.

 

If you need high discharge rates comparable to a large 9.6, a good quality 7.2v LiPo would be the best option.

 

Sub-C cells are just too wide to fit inside the stock, and to make them fit, you would have to hollow out the stock to the point that a strong breeze could crack it.

[uscmCorps]

I write quite a lot of tutorials. THIS... what you have here... is a GREAT tutorial. Well written and concise. Very nicely done. And your G3 is spectacular!!!

[Pariah_WP]

11.1v LiIon or LiPoly stick/bar batteries are not becoming available that can fit into the CETME stock furniture with little modification, so people might want to consider that as an option to running an external battery. All the usual caveats apply, so make sure your gun can run a LiPo before considering this battery option.

 

Nice tut!

[Maple-Leaf]

WOW! Awesome project, and GREAT step-by-step guide. You sir are THE MAN.

[chas]

Very nice! Kudos on that beauty!

 

But.... you NEED the triangular rear sight. World of a difference, IMO:

 

 

Some spanish dudes took the time to make it, seemed hard. The link is in spanish, so if you want to make the rear sight and need help with the translation, PM me. Or get in touch with H_U_M, the guy who made the mock sight; I think he has an account on arnie's.

 

http://www.airsoftbarcelona.com/ldu/forums...;q=6327&d=0

[James Kelly]

I understand enough Spanish to understand the general gist of what is being said. Thanks for the offer though.

 

I'll do what I can to work out a way of making the rear sight, but if it comes down to it, I think that I'd prefer to have a clean looking incorrect sight over a shoddy recreation.

[10percentcharlie]

I wish I found this guide before I did mine, but it came out fine all the same. I wasn't sure if I could put the endcap on the foregrip or not, but I'll try it with part cut off like you did. I was wondering, did your wood come stained like it shows in your pics, because the wood I got is very lightly stained.

[James Kelly]

I wish I found this guide before I did mine, but it came out fine all the same. I wasn't sure if I could put the endcap on the foregrip or not, but I'll try it with part cut off like you did. I was wondering, did your wood come stained like it shows in your pics, because the wood I got is very lightly stained.

 

No, mine came unfinished and sticky with what was probably cosmoline.

 

I washed it with water and alcohol, and got most of it out before I sanded, stained and shellac'd it.