Cetme Build Tutorial (Take 2)

[pjm204]

If you're reading this thread you may have been following my build tutorial before the old forum hit the dirt. If so, you will be glad to know that I am continuing the tutorial here and saved all the images from the old thread. I didn't save the text but will try to fill it back in as best as I can. Alright, here we go.

I started out by ordering my Cetme kit from Centerfiresystems for the great price of $100. I had heard that some of the kits were in rough shape but mine turned out to be quite nice. It had a cracked pistol grip but the internals showed very little wear and of course the barrel is new. Below is a picture of my kit.

I started my build by disassembling everything, mainly to familiarize myself with the functions of the parts and try to get a good grasp of how they all fit together. I removed the selector lever, then pulled out the FCG box. The ejector spring was removed next, followed by the ejector pivot pin, and then the ejector. I then drove out the pins holding in the rest of the FCG, and was left with the empty box. I stored these parts with exception to the ones not needed(shown below) in a bag and made sure I wouldn't lose them.

Next I went on to press out the pin which holds in the charging lever, this is done by bringing it back to the charged position and lining it up with the holes on top and bottom, it pressed out very easily, could be done with a punch and hammer too. Be careful not to loose the spring.

I was now ready to remove the trunnion and cocking tube. This was done by grinding away all the spot welds. Most of the spot welds are easily identified by depressions in the metal but there are 3 or so(one on top of the cocking tube, and two on the trunnion) which are only seen by discoloration in the finish, they appear darker. The cocking tube can be separated from the rest of the receiver scrap by following the seam between the upper(smaller) and lower(larger) "tubes" of the receiver. Once they are separated they can be tackled one at a time. Once, you have ground the welds flush, you can peel away the receiver scrap from the cocking tube. Be careful not to deform or removed metal from the cocking tube sleeve. Next peel the receiver away from the trunnion, I found the trunnion to be quite easy since you are less worried about damaging it. Pictures of these parts are found below.

[pjm204]

Modifying the FCG and FCG box to fire semi-only was the next step I took in the process.

You will need to completely remove where the third pin would go by cutting the front lower corner out of the box. This is shown "clearly" in a picture below. The measurements are roughly .4" up and .5" back, I just tried to match mine as closely to the pictures I've seen of other modified boxes. Once this is done a small peice of sheet metal needs to be welded in and then ground flush, this is also shown below.

Certain tails and trips are ground away on the FCG which was done easily with a bench grinder and took less than 10 minutes.

[pjm204]

The previous posts were from my original thread. Since then I have received my CIA stamped receiver(its no JLD I know) and some of my compliance parts. Had a few things slow me down, the package with my US forearm was stolen off my porch, and my US pistol grip wasn't in the package in my order from CFS. I think I have resolved both problems now but no parts yet. On a brighter note, I bought a bead blast cabinet at HF for 45 bucks so I blasted my cocking tube, box, and some other parts. I need to grind some parts on the receiver so that the stock fits on and the holes line up, also need to grind a bit so the mag fits better and the trunnion slides in better. Other than that I should be able to turn a heatsink to weld my cocking tube in today, and I should be able to cut the "ears" off of my lower, possibly make my shelf. I hope to have this thing done in the next couple of weeks.

[Schultz]

Keep the info coming, Great work!

[Smokehouse69]

I was wondering when you were gonna re-post the info. You were able to get a "stamped" receiver from CIA?? I thought all they had left was cast receivers!

[pjm204]

My dealer didn't seem to have any trouble getting a stamped receiver. So far it seems to be pretty "in spec". I had to grind the weld in the rear to get the stock on and some other minor issues. I got the ears cut off tonight so I can post pics of that soon, probably after I make a shelf and weld it in.

[Smokehouse69]

Thanx for the information, I'm going to stop by my dealer tomorrow (if I get off work early enough) and see if he can order me one! I wanna get started on this thing!

[pjm204]

Let me know how much your dealer charges, I know they cost 139 but thats definitely not what my dealer charged me, but sadly I don't have an FFL so I was at his mercy.

[Smokehouse69]

Well, I don't know for sure, but if it is much more than, $139 +$25 transfer + $11.50 tax + $8.00 shipping, or $185.00, I'm gonna check with a different dealer!

[pjm204]

mine was 200 bucks out the door, I was going to ask why they charged so much but it wasn't worth it, they were nice and they did have to call century several times. Supply and demand I guess

[vista461]

The guy I used was great.
I called my century rep(I have a C&R) she told me to have the FFL call her and fax his license. He did. I paid century their money and I paid him the transfer money. 139+8+20=167. I found the FFL on the Gunbroker search area and he's like 5 min from my house:woohoo-1:

[Seattlefungus]

I just went on the Century site. (I'm a dealer). The Stamped receiver for the CETME is not listed. Just the cast. I'll have to talk to my sales rep. (I have to make an order any way) to get the scuttlebutt...

[Otis61]

pjm204 thanx for all the good info. I just put one together a couple weeks ago. Mostly I used material for a g3 build, but didn't know what to do about the triger pack until I saw your thread on the old forum. I'm glad to see everything coming back.And thanks for your help.

[pjm204]

Otis, is yours finished, if so, post pics, and a range report. I still have a bit of work to do but last night was the first time I was able to slide everything into the receiver and make it look like a gun, which was cool. I still need to check the bolt gap and everything.

[bubbamauser]

PJM,

Thanks for trying to recreate the post Perro, took me through to completion on CetmeRifles.com,(I got an centerfire systems CETME parts kit now what) Funny I don't remember any of your posts on that thread though. if you need any of more of the originals ask and I'll send them over.

Thanks Perro for making my and PJM's builds possible and thanks for the grip screw rusty
http://i21.photobucket.com/albums/b290/bubbamauser/cetme%20before/cetmebefore2.jpg

http://i21.photobucket.com/albums/b290/bubbamauser/cetme%20before/Triggermods1.jpg

http://i21.photobucket.com/albums/b290/bubbamauser/cetme%20before/Receiver1.jpg

http://i21.photobucket.com/albums/b290/bubbamauser/cetme%20before/Modedboxandpawl.jpg

http://i21.photobucket.com/albums/b290/bubbamauser/cetme%20before/cetmetrunionwelded.jpg

http://i21.photobucket.com/albums/b290/bubbamauser/cetme%20before/cetmecomplete3.jpg

[pjm204]

Bubba, I had actually started a tutorial back on cetmerifles, so I am recreating that thread. I only got to look at the thread you are referring to briefly before the site crashed.

Update: I have the trunnion welded in and the barrel pressed and pinned. I decided to leave the receiver undrilled for the barrel pin as I don't plan to wear out the barrel ever, if I do, then I will drill it then. I'm still trying to locate a piece of copper or aluminum big enough to use as a heatsink, I had turned down a copper nipple but it squashed as I was finishing it in the lathe(too thin anyway). I will probably work on the shelf tonight and possibly weld it in.

[grifter95]

Where are ya'll getting the shelf that is welded into the grip housing (not in the trigger box)? Are ya'll fabricating them yourselves?

[pjm204]

FAC used to sell them but to the best of my knowledge, no one currently sells one. So making it is the only option, oh, or having someone else make it for you. It shouldn't be too difficult.

[vista461]

Any new progress PJM?:D

[roland3]

hey pjm, am i correct in saying you have to discard the hammer and get a different one? if so are there other parts you have to buy to convert the fcg to semi auto?. and could you post a couple pics of the shelf welded in and where it goes, i dont quite understand how that works. thanks!

[pjm204]

no, you do not need to discard the hammer, the picture I posted on the previous page shows the parts you discard. I haven't made my shelf yet, I should be able to do that tonight, hopefully. I'm still trying to locate a peice of copper or aluminum rod, I started to turn down a copper rod only to find steel in the middle. Otherwise my cocking tube would be on, i'm thinking about drilling through 50 pennies and then screwing them together.

[hulygan]

PJM, if you go the penny route you need to use older ones i think pre 1980. any of the newer pennies are 98% zinc with a copper cladding. why not go to the hardware storem buy a peice of copper pipe and stuff an aluminum rod into it.

[roland3]

im confused, your making the shelf out of copper or alum? how do you weld it in then?

[roland3]

century rand out of parts kits yesterday and I got the second to last one from a different supplier. I ordered my cast reciever today and my dealer said that century had only 10 recievers left.

[hulygan]

Roland, the shelf is made out of steel, the copper and aluminum are for making a heat sink to put in the cocking tube and reciever for when you weld it. THe heat sink help to keep you from burning through the cocking tube when welding it to the reciever

[roland3]

oh got it.

[remauto1100]

Newbie questions ALERT!

Should trunion be welded into receiver first...then install cocking tube and weld?

When trunion is welded in receiver should barrel be pressed into trunion first?

Press barrel in from muzzle or chamber end of trunion? How far into trunion should barrel be to end up to safely measure bolt gap and end up with a "correct reading"?

Anything else I should be concerned with at this point?

I am using a JLD PTR91 receiver with all Cetme parts including new cetme barrel. Receiver is getting true HK91 front and rear sight.

Thank-you for any help you have to offer!
Appreciate it!

Mike

[KMURPHY]

The guy I used was great.
I called my century rep(I have a C&R) she told me to have the FFL call her and fax his license. He did. I paid century their money and I paid him the transfer money. 139+8+20=167. I found the FFL on the Gunbroker search area and he's like 5 min from my house:woohoo-1:

you from west allis? BCM screenname rocketpower? Its kevin (murphyslaw88gt)

[rustypirate]

Newbie questions ALERT!

Should trunion be welded into receiver first...then install cocking tube and weld?

When trunion is welded in receiver should barrel be pressed into trunion first?

Press barrel in from muzzle or chamber end of trunion? How far into trunion should barrel be to end up to safely measure bolt gap and end up with a "correct reading"?

Anything else I should be concerned with at this point?

I am using a JLD PTR91 receiver with all Cetme parts including new cetme barrel. Receiver is getting true HK91 front and rear sight.

Thank-you for any help you have to offer!
Appreciate it!

Mike

Mike,

In answer to your questions....

You must install the trunion before welding the cocking tube because the cocking tube interferes with the fit of the trunion.

If your trunion already has the barrel installed AND the measured bolt gap is acceptable to you, you can install the trunion with the barrel pre-installed. However if your barrel and trunion are not already mated, it is advised to install the trunion first, then pressin the barrel, set the bolt gap, and pin it.

It is better to press the barrel in fron the rear to front. This uses the taper on the profile of the barrel to keep it centered in the trunion as it is started into the trunion.

As for how far to press the barrel, search this forum for bolt gap or barrel press to find the correct procedure.

The only other thing to be concerned about is the correct length of the cocking tube in relatin to to the bolt carrier. If the tube is too short, then the bolt carrier will collide with the charging handle support when the bolt tries to go into battery. this can cause damage to the cocking tube, but more importantly it will prevent the bolt from locking into the trunion correctly. (UNSAFE) If the tube is too long, then the charging handle will not have enough contact to lever the bolt carrier to the rear to unock the bolt.

You should have between .010" and .020" of space between the charging handle support and the plug at the end of the cocking tube with the bolt locked into battery.

I hope that this helps.

rusty

[remauto1100]

Great Info and I really appreciate it.

I am however not sure where to make my measurements on your last setup procedure. The .010 to .020 gap.

I believe you are tlaking about the cocking tube gap where it almost goes up against the face of the trunion. (This is the weld that has to be ground off of a parts kit to remove the cocking tube)...right?

I saw the procedure for putting the spacer inside the cocking tube but I am not 100% sure I fully understand that part to get the cocking tube in place to weld to the trunion. ( I assume with a mig welder?)

Told ya I was a newbie to HK/Cetme's :bash:

[texlurch]

Great Info and I really appreciate it.

I am however not sure where to make my measurements on your last setup procedure. The .010 to .020 gap.

I believe you are tlaking about the cocking tube gap where it almost goes up against the face of the trunion. (This is the weld that has to be ground off of a parts kit to remove the cocking tube)...right?
Told ya I was a newbie to HK/Cetme's :bash:

NO, he is referring to the front of the cocking tube (muzzle end). With the bolt locked up, cocking handle installed, and good bolt gap measurement, you should have a .010-.020 gap between the front of the handle support and the end of the tube.

[rustypirate]

Tex is correct.

the easiest way to measure this is to install the cocking tube, then insert the charging handle support without the charging handle. Last insert the bolt carrier assembly and lock it into the trunion. You can now measure the distance from the forward end of the charging handle support to the plug in the forward end of the cocking tube.

I found a sewing needle works best.

If you can fit it without drag, then you have at least the minimum gap.

If a thick paper clip wire will fit, then it is out too far.

[vista461]

you from west allis? BCM screenname rocketpower? Its kevin (murphyslaw88gt)
Woops have checked this thread in a while, yep it's me

[remauto1100]

When pressing barrel into trunion, does the gace of the barrel(chamber) sit flush with the trunion face or ???? This is a new Cetme barrel I am dealing with. (Centerfiresystems kit).

Heat trunion up and stick barrel in freezer before pressing?

Mike

[Otis61]

No. Check the bolt gap threads. Press the barrel until the barrel protrudes uot the back of the trunion sevrel thousands of an inch. Then check gap. Adjust acordingly. athen drill, and pin.Start with the origina pin relief in the barrel on top, so that you drill a completly new one.