PDA

View Full Version : original fal receiver blueprints


praff
November 02, 2017, 09:19
Ok so just to set the record straight before anyone asks, yes I am a manufacturer and have a current 07/02 license. Rafferty Custom Guns, LLC for anyone that wants to look. I have been gunsmithing for a few years under an 01 and just received a new 07/02 and am going to make a few post dealer samples. One of those is gonna be an FAL.

I have all parts and have a good understanding of what needs to be done, but, i can't wrap my head around how the safety sear operates properly in a full auto cut receiver. It appears as if the ears on the lower would want to "pinch" the safety sear and not allow it to function properly. This is due to the clearance cut on the receiver and how the two halves mate up when connected. It just seems as if the sear would rub on the ear of the lower, but maybe I'm missing something or not seeing a shoulder or bushing somewhere.

So looking for a little better understanding here and a proper drawing would be a great help. I can't seem to find a good drawing anywhere that details the width dimensions of the lug on the upper receiver for milling.

Any help would be greatly appreciated

Pat


also...edited to add pic and maybe ask for info on this particular flash hider/thread pitch. Would like to change the muzzle device and curious if anyone knows whether this is rh or lh threads and maybe if these were permanently attached or not. Looks like it is a early tapco muzzle break and the rifle is on an embel gear logo receiver. I don't know history on this other than it had the black plastic furniture and I added the izzy light barrel stuff a couple years ago.

http://i65.tinypic.com/dcu2o9.jpg

4markk
November 02, 2017, 10:09
You got it .... the "safety sear" is held in place by the hinge pin. The relief cut on the receiver allows the long leg of the safety sear to go up through the ejector block so that it can engage the carrier.

As for the muzzle device, the one in your pic is a TAPCO version of an Austrian Stoll Device (LH Thread). In my opinion the REAL Stoll is the best one for the FAL. It not only reduces flash, but dampen barrel harmonics and disrupts transitional ballistics.

praff
November 02, 2017, 10:18
just seems like it is kind of a shitty design as the ears aren't supported then (well the safety sear side anyway). Seems like it would induce a little slop, but maybe i just need to cut it and see.

:biggrin::biggrin::biggrin:

notfrommt
November 02, 2017, 10:25
Congrats on the 07! :fal:

Safe to assume you also paid your SOT and ITAR?

praff
November 02, 2017, 10:32
Congrats on the 07! :fal:

Safe to assume you also paid your SOT and ITAR?

i am completely compliant with all federal and local laws as i stated in the original post....this is one reason i was hesitant to post here. I stated i had my 07/02....the 02 part is the sot and if you would read the original post and not assume someone is trolling and or trying to break the law, you would see that i am compliant. i even put my business name in the op so you could look me up, but I'm sure you didn't take the time to do that either. All i am looking for is accurate information and trying to learn a little more in my journey as a gunsmith and manufacturer

and sorry for the crass reply, but its hard enough complying with the government, then getting fingers pointed at you on the internet just kind of is like pouring salt on the wounds

notfrommt
November 02, 2017, 10:42
No worries and I understand. The congratulations were sincere!

praff
November 02, 2017, 11:09
No worries and I understand. The congratulations were sincere!

Thank you sir!!!

I even moved my residence as the county i was living in wouldn't allow me to get my 07 or do sales/transfers. Thats why I started with an 01 rather than an 07 to begin with. We now have moved into a new home with my shop in the walkout basement. The whole thing has been a blessing as we couldn't be happier with the new home and a little land in the country.

lew
November 02, 2017, 11:42
The muzzle threads- assuming they are unaltered- will be 9/16-24 LH. I'd take that one off and get one of DSA's titanium combo devices. You will notice a considerable change in the feel of the rifle with all that weight off the muzzle end. I have one on of of my R1 clones.

4markk
November 02, 2017, 12:34
just seems like it is kind of a shitty design as the ears aren't supported then (well the safety sear side anyway). Seems like it would induce a little slop, but maybe i just need to cut it and see.


The ones I have, have a pretty good fit on the hinge pin, not really any slop. Side to side movement is limited by the "ears" of the lower which are pretty strong, not to mention being held by the hinge pin. So all in all, it is more stout than you may realize.

Archilochus
November 02, 2017, 14:52
just seems like it is kind of a shitty design as the ears aren't supported then (well the safety sear side anyway). Seems like it would induce a little slop, but maybe i just need to cut it and see.


Check the third pic down in this link:
http://www.falfiles.com/forums/showthread.php?s=&threadid=262315

There are partial 'shoulders' top & bottom to support the trigger housing's 'ear's on the sear side.

praff
November 02, 2017, 16:45
Check the third pic down in this link:
http://www.falfiles.com/forums/showthread.php?s=&threadid=262315

There are partial 'shoulders' top & bottom to support the trigger housing's 'ear's on the sear side.

Ahhhhhh....now i see

I think ive seen that thread and just never noticed that detail. So now i really nead a copy of the drawing or print. I think i saw a thread in here with someone that may have had original receiver drawings. I will dig a little more with a couple searches.

Archilochus
November 02, 2017, 17:20
I think i saw a thread in here with someone that may have had original receiver drawings. I will dig a little more with a couple searches.

There were some FN prints for sale in the classifieds a while back. If you can contact one of the people involved in the sale, maybe they'll send you pics of the area you're interested in.

notfrommt
November 02, 2017, 17:23
There were some FN prints for sale in the classifieds a while back. If you can contact one of the people involved in the sale, maybe they'll send you pics of the area you're interested in.

email sent

bigstick61
November 03, 2017, 05:40
The depth of the cut on the upper receiver by my measure is exactly 5mm. If you look at the flat portion of the underside of the receiver to the rear of the hinge pin before it curves upwards and to the rear, everything below that is cut except for a tiny section at the bottom. No other cut is made to the receiver itself.

Using a sear-cut ejector block should eliminate the need for cutting one.

praff
November 03, 2017, 05:49
The depth of the cut on the upper receiver by my measure is exactly 5mm. If you look at the flat portion of the underside of the receiver to the rear of the hinge pin before it curves upwards and to the rear, everything below that is cut except for a tiny section at the bottom. No other cut is made to the receiver itself.

Using a sear-cut ejector block should eliminate the need for cutting one.

5mm sounds about right.....i havent measured the thickness of the sear, but that seems about right with a little clearance on each side of the sear.

I have the correct ejector block to allow the safety sear to function correctly.



Thanks to everyone for the information

bigstick61
November 03, 2017, 06:27
Some pictures:

https://farm5.staticflickr.com/4563/37426433464_2bbed0300a_b.jpg

https://farm5.staticflickr.com/4499/37426433454_2295aba645_b.jpg

https://farm5.staticflickr.com/4575/37426433414_2911a66d24_b.jpg

gunplumber
November 03, 2017, 10:19
The hinge pin is of such length that when fully tightened does not allow pinching of the sear. Additionally, as Archilochus said, there is a shelf top and bottom, indicated by the red arrows on my image.The sear width is appx .005" under the shelf height of .175-.171". I just converted and IMBEL to full auto yesterday and took the measurements off an Enfield for curiosity. But you don't need any measurements. You can totally eye-ball it. Put your FA e-block in first. Cut depth to match e-block. Cut up to same as lowest point of receiver wall. This will leave the top shelf. Cut down to highest point of hing pin head radius. This will leave a long bottom shelf. Then cut down to remove all but a little finger of the bottom shelf. Took me about 10 minutes with a 1/2" end mill.

According to the UK print, height to bottom of cut from centerline is .176-.004 and to top of shelf is .356-.003. 355-172 = 180 This corresponds closely to my measurement of a UB58 that concludes with "cut slot .175 "

FN print says 4.45 +/-.05mm from outside wall to bottom of cut, which, converted to inches, is .175"

On a semiauto, I reduce the height of the hinge pin by .003-.005" to deliberately pinch the ears for tighter lockup.

http://www.arizonaresponsesystems.com/wp/fal/fal-receiver-safetysear-cut.jpg

praff
November 03, 2017, 13:13
The hinge pin is of such length that when fully tightened does not allow pinching of the sear. Additionally, as Archilochus said, there is a shelf top and bottom, indicated by the red arrows on my image.The sear width is appx .005" under the shelf height of .175-.171". I just converted and IMBEL to full auto yesterday and took the measurements off an Enfield for curiosity. But you don't need any measurements. You can totally eye-ball it. Put your FA e-block in first. Cut depth to match e-block. Cut up to same as lowest point of receiver wall. This will leave the top shelf. Cut down to highest point of hing pin head radius. This will leave a long bottom shelf. Then cut down to remove all but a little finger of the bottom shelf. Took me about 10 minutes with a 1/2" end mill.

According to the UK print, height to bottom of cut from centerline is .176-.004 and to top of shelf is .356-.003. 355-172 = 180 This corresponds closely to my measurement of a UB58 that concludes with "cut slot .175 "

FN print says 4.45 +/-.05mm from outside wall to bottom of cut, which, converted to inches, is .175"

On a semiauto, I reduce the height of the hinge pin by .003-.005" to deliberately pinch the ears for tighter lockup.

http://www.arizonaresponsesystems.com/wp/fal/fal-receiver-safetysear-cut.jpg




Great information. All makes sense now after looking at a few pics and seeing it done. I really appreciate all the responses and information. I like the thought of reducing pin height to pinch ears on a semi....great idea.

thanks again
Pat

Thomas
November 03, 2017, 14:40
Just buy some cut up receiver parts on gunbroker for measuring.

praff
November 03, 2017, 16:00
Just buy some cut up receiver parts on gunbroker for measuring.

Thats an idea I never thought of as well!!!!

bigstick61
November 03, 2017, 17:14
Yeah, the sear-cut receiver in my pictures is a cut-up IMBEL one I got in the Marketplace here.