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View Full Version : Lithgow forging, (re)discovered!


gunplumber
September 25, 2017, 14:05
So I had this receeier blank from EAI. I'd assumed was billet, but in the discussion of DSA's false advertising and selling their cast receivers as "forged", I took another look at it. (Part of my extensive research and documentation, donchaknow!)

I noticed the roughness at the bottom of the mag well, and thought to myself, ok, that part is "as cast". But it was an interesting texture. Then I saw the Lithgow steel batch mark on the front web. I guess it's a forging.

I don't know who did the work, but I found the sequence of operations interesting.

I also note the tool marks on the flat an am thinking "blanchard cut", which is unusual for a modern operation. This leads me to believe the cuts are from Lithgow. I also note the LS and hinge pin holes are first; my understanding is that all critical dimensions are referenced from these holes. That makes Coonan's badly drilled & oversize LS hole more curious - what's he using for a reference point?

http://www.arizonaresponsesystems.com/wp/fal/l1a1-receiver-forging-lithgow-01.jpg

http://www.arizonaresponsesystems.com/wp/fal/l1a1-receiver-forging-lithgow-02.jpg

http://www.arizonaresponsesystems.com/wp/fal/l1a1-receiver-forging-lithgow-03.jpg

Thorack
September 25, 2017, 14:21
GP,

Very Nice. I remember seeing an "In Progress" Box that Pat (SLR-5000) used to have that had 8 or 10 Lithgow receivers in a progressing level of finish. Always fascinated me.

Thorack

ActionYobbo
September 25, 2017, 14:32
If you want to sell it (them) I am interested in getting them. They make nice receivers when finished.
These are the same as the armscorp receivers.
There was 10 stages of machining. The reciever you have is at stage 6 and looks like all the other Lithgow forgings I have seen. I have several that came via armscorp that look the same as that.

gunplumber
September 25, 2017, 15:17
Only have one. This was not meant as an ad - I was keeping it as a curiosity, but that doesn't pay the electric bill.

I can just keep the pics for reference. If there are any pics of the other stages, that would be cool to see.

E-mail me gunplumber@arizonaresponsesystems.com with a fair offer. I have no emotional attachment to it, and haven't the skill or equipment to finish it.

kev
September 25, 2017, 16:13
Dealer Showroom used to advertise a complete set of those in various stages of completion in the original box. I'm sure I've got the pics and description stashed away somewhere deep in this computer but haven't been able to locate them. Dealer Showroom website is no longer broadcasting. Always wanted to buy a/the(?) set but never had a spare grand floating around. Can't now remember whether it was eight, ten or twelve in the set. I don't think any of them were as far along in the process as the Entreprise receivers you had strapped into the tombstones. BTW, John required an FFL for shipment of the 'in process' Lithgow receivers. Never really thought that was necessary. What would you put in the A&D? "Box of unfinished receivers,....NSN"?

mountainman
September 28, 2017, 18:01
lower picture of the flat looks like some big indexable cutter decked that and then the one above that I can't make out anything from the scratches on that.

NZ L1A1 Collector
October 01, 2017, 21:07
The photo is from a display at Lithgow SAF Museum, sorry about the quality it was taken a long time ago but does show the initial product before any work starts.

The dash lines are reflections off the carpet onto the glass cabinet

http://i129.photobucket.com/albums/p236/nzl1a1collector/Parts/Receiverblanks_zpsptmwy5gy.jpg

Rudolf
October 02, 2017, 07:15
Pat Jones had a couple of those at the gun shows.

fal762
October 05, 2017, 21:54
I know I'm late to this but is this any help?
http://www.gunsandgunsmiths.com/fal-receiver-machining/

gunplumber
October 06, 2017, 08:07
I know I'm late to this but is this any help?
http://www.gunsandgunsmiths.com/fal-receiver-machining/

Great video. Much better than Johns other AGI disaster.

Just kidding - to his credit, John had no editorial contribution to the AGI video. It was so bad that is was my motivation to make my own - which has helped thousands of home and professional builders. So it was really to my benefit that it was teh Sux.

Archilochus
October 06, 2017, 15:31
If anyone would find it at all interesting, I had finished the machining on one of these forgings. Lots of work for a one-off!
http://www.weaponsguild.com/forum/index.php?topic=55207.0

tdb59
October 06, 2017, 15:57
I know I'm late to this but is this any help?
http://www.gunsandgunsmiths.com/fal-receiver-machining/

I have leaned against that bookcase a few times.





Great video. Much better than Johns other AGI disaster.

Just kidding - to his credit, John had no editorial contribution to the AGI video. It was so bad that is was my motivation to make my own - which has helped thousands of home and professional builders. So it was really to my benefit that it was teh Sux.

I always enjoy visiting with John. His knowledge of military firearms and their operation is astounding.

..............

ActionYobbo
October 06, 2017, 19:37
Nice video but its not correct. He made an assumption that the machining was indexed off the front. It is not. All finishing machining operations are indexed off the locking shoulder hole. The forging is roughed down to basic shape then the locking shoulder hole is bored and from then on it is the index point.
I have several of these receivers and when they are all lined up with a rod through the LS hole the fronts are not even but the rears and all completed internal machining are even.

gunplumber
October 06, 2017, 19:44
Nice video but its not correct. He made an assumption that the machining was indexed off the front. It is not. All finishing machining operations are indexed off the locking shoulder hole. The forging is roughed down to basic shape then the locking shoulder hole is bored and from then on it is the index point.
I have several of these receivers and when they are all lined up with a rod through the LS hole the fronts are not even but the rears and all completed internal machining are even.

Correct!

The prints are made with all dimensions referenced off the LS and hinge holes. Something US manufactures should bear in mind.