T48 CH

[mountainman]

T48 CH. How did that make those without CNC back in the day? Anybody got any idea if they used some sort of pantograph mill or something? Just curious. I plan on roughing on the mill fitting by hand and trying it out against a master form. The feature that I am talking about here is the curved knob part.

[RPBII]

Forged maybe?

[mountainman]

Finish clearly looks machined.

[Raspeguy]

Originally Posted by mountainman

T48 CH. How did that make those without CNC back in the day? Anybody got any idea if they used some sort of pantograph mill or something? Just curious. I plan on roughing on the mill fitting by hand and trying it out against a master form. The feature that I am talking about here is the curved knob part.

Doesn't look like you're getting much feedback, Effendi! Before the time of CNC and NC, there were machines such as the various Cincinnati Hydrotels. These needed a template for the tracer probe to follow for simple stuff or models for 3d parts, although I believe they only profiled in one axis for the big horizontal versions???

Say you were going to rough out the cavity for an automotive floor pan die. You would have the die casting already machined externally of course. A pattern shop would make the plaster model from the master part model. These would both be mounted to a large plate and aligned as needed. Then the plate mounted to large angle plates on the machine's table. The cavity would be machined primarily?? using ball end cutters with the tracer probe having the same spherical size. As the features became more defined and smaller, smaller ball mills with matching probes would be employed. Best I remember, the spindle was moved up and down (Y) on the column while the table moved in and out (Z) as the model was traced. Single line tracing. Cut, move over in (X), and repeat, repeat, repeat. Due to the time that would have been required to make the die near net shape, they were not that far progressed before taken off the machine. It was more economical for it to move to a spotting press and be worked in by die grinders, files, stoning to a model made from the master with the final touches from the similarly finished punch half. I didn't work in the machine shop and this is from memory, not hands on experience. This was in the latter 60s and do believe this equipment was originally WW2 surplus??

FN in the 1950s was old technology. Lots of small, separate operations on parts and cheap female labor (pigs as they were derisively called because of their smell at the end of the shift, as much was due to the odor of cutting oils and summer sweat shop temperatures). And they probably didn't make a lot of T48 charging handles. There isn't much difficult about the "knob". So here's my $.02 and that's all its worth. The front of the "knob" where you would hook your finger around is a simple profile cut made on a arc. For the finished shape you need a special ground form tool or profile cutter. The front part of the "knob" is rotated into the form cutter on its desired arc radius. There would be a fixture to hold and position the part and the means of rotation may as well have been incorporated into the fixture or a rotary table on the machine or part of it.

Conversely, if more sophisticated machinery was available the part could have been stationary and the head swung in any desired arc. Who knows all the special purpose machinery that was designed in the manual heydays, long forgotten if remembered in the first place, eh? A poor boy would just need an expensive form cutter, rotary table and fixture to hold and position correctly the part on the rotary table for the correct arc swing. As described this method and part/cutter motion would satisfy the generation of the small fillet at the front base of the "knob" as well as the small external radius near the outer end of the "knob's" front profile.

Not sure from the T48 images posted about the rear edge of the "knob", "knob" as you called it. It could have be done as described above. Since the pictures are not difinitive in my mind as to show the lay of the finish. The rear edge could have been machined "along" the length of its edge. Assuming this second option and the poor boy method, again using rotab, part fixture, and concave radius cutter (another special item). The rear of the "kanob" has both a concave and convex profile. First you require a concave cutter that has the correct arc radius (whatever is on the orgininal T48 across its thickness) plus the diameter of the cutter has to match the concave portion (arc) on the rear edge of the "knob" AT the "knob's" thickness. With the part properly fixtured and located on the rotab, the mill table advances the cutter into the "knob" to generate the concave feature, advance stopped, then the rotab is rotated to generate the convex feature. Naturally, the fixturing location of the part relative to the rotary table center determines the arc on the convex portion and is of the utmost importance. This "second" option is based on what I can see, or think I see, of the T48 in the Image Galleries forum?

Nowadays with a 2 and 1/2 axis mill (minimum) and a single, appropriate, and basic profiling mill cutter, the complete front and rear of the T48 "kanob" can be machined like the original in one single setup position, with the part either positioned with the "kanob" vertical or horizontal. Naturally, you would have cusps, but these can be quite small to nearly non-existant depending on the number of passes/steps and zipped away quickly on a belt sander, or shoe-shined by hand, if you wanted to take the finish further.

Like I said, you just got 2 pennies worth of thought and a couple proof reads, subject to change . Hopefully, the explanation was adequately presented on my part?

Correction: It occurred to me without rereading my text, that the CNC "single" setup with part positioned horizontally is invalid. The front underside (bottom half of front) would present a big problem to develop the small base fillet and to blend the profile portion near it with any kind of practical cutter. The fillet is quite small. Even in carbide with a small shank (.25" dia. or slightly less) plus the cutting portion would result in a minimum radius far larger than the base fillet on the knob/slide intersection. This part (knob) positioned vertical like a smokestack with proper support and method is the superior choice if one was to employ profile milling. Another 1/2 cent added. I've been out of this **** trade for nearly 4 years and don't miss it or think about it anymore.

[torquemada055]

Dang you machinist guy's are amazing....

[Raspeguy]

Originally Posted by torquemada055

Dang you machinist guy's are amazing....

It may seem amazing to you and I say that with absolutely no hint of derogatory sentiment towards you, ....but taken within the total scope of the metalworking trade I consider the extent of my skills and knowledge to be very underwhelming (miniscule) with a good bit of underdevelopment in potential on my part. However, amongst my peers at any place or point in time I was among the best. Big deal, not. The things that soured me, and certainly not exclusive to the trade alone, was all the C/S politics, backstabbing, and D-sucking, bloated egos, excessive hours, and relatively diminishing wages that went increasingly on as time progressed. Signs of the times everywhere, eh! Like "Temp" once said here to effect, "great hobby, p-poor way to may a living". For a long time, looked forward to the retired hobby aspect, only to arrive essentially devoid of any enthusiasm, coupled with the realization it would have ended up driving me. I remember the high enjoyment and drive of many hobby projects in younger times. Many. Now, am reasonably content to be just a lazy bum and learn more, intellectually speaking, of the world, history, the times of the great african hunters, discover the wonderful music I missed unbeknowgst to me, observe the human circus, and so it goes until the cork pops!

[G_FAL]

The "hook" type charging handle was made by Harrington & Richardson , not FN.

[Raspeguy]

Originally Posted by G_FAL

The "hook" type charging handle was made by Harrington & Richardson , not FN.

Correct for the most part about H&R, along with a handful made by High Standard. However, FN did produce a "hook" type charging handle although it varied slighltly from the T48 style a wee bit that was produced in the H&R trial run. As to how many were made?? If you can make a copy of the one, you can make the other.

I can't post a picture, but if you were to go to the archive website that houses pictures from Springfield Armory it can be seen. At the time I downloaded it a few years back the opening link was http://www.rediscov.com/spring.htm. The site's navigating structure left something to be desired at that time.

"Rifle, Lightweight, Caliber .30, Fabrique Nationale - s/n#37 With Special Operation Slide". Picture is dated 3 March 1954. This one is sufficiently detailed as is another picture with the acceptance marks clearly identifiable on the receiver ring.

There are other pictures of their collection, but their extremely poor size and resolution makes some distinctions somewhat dubious.

[NHBandit]

An absolutely exact copy of the hook type CH also requires the special compatible receiver. It does not use a spring loaded detent anything like the standard metric variety. http://img.photobucket.com/albums/v2...ntico08091.jpg Raspeguy is this what you were looking for ? http://www.falfiles.com/forums/print...t=254976&pp=40 The Springfield Armory Museum also has alot of different T48 versions and I agree, the pictures suck. Someone needs to get access to the "pattern room" on the second floor and spend a day taking detailed pictures. They do have an amazing collection but that section of the museum is closed to the public. How about a .22 caliber T48... http://ww3.rediscov.com/spring/VFPCG...ABASE=41549100, Or if anyone has a lower & buttstock like this I will pay dearly for it.. lol http://ww3.rediscov.com/spring/full/...0548491446.jpg To access most of the small, not very detailed pics of the rifles at the Armory go here... http://ww3.rediscov.com/spring/ Then choose "Object Descriptor" and type in FN T48 & hit search. One of our members with lots of spare time on their hands really should get permission (from the National Park Service) to spend as long as it takes to fully document each variety of T48 in this collection and there would be enough info to write a book. The Armory collection is no longer under the jurisdiction of the military. The ones in Quantico are cool but there is nowhere near the huge variety of different experimental versions, modifications, etc as there are in Springfield. We need someone with the same dedication Pat had when he went to Quantico to go to Springfield and take the same sort of high quality pics. Any volunteers ?

[Raspeguy]

Originally Posted by NHBandit

An absolutely exact copy of the hook type CH also requires the special compatible receiver. It does not use a spring loaded detent anything like the standard metric variety.

Yes, which is why I expect this isn't going anywhere? I see two options with today's receivers. One, if the hook was to remain in the same relative position on the slide as the T48, you have the problem what to do with the plunger that keeps the charging handle in place. Second, if a facsimile hook was moved to a forward position to where the round knob is now it would be possible to incorporate the plunger and lug within the hook. There might be a problem?? with the cavities breaking out into the hook profile thereby requiring a wider hook or the use of at least an offset plunger. Seems the OP went AWOL on his thread. The hook has no appeal for me.

NHBandit, it would be nice if a definitive and high quality photo shoot could be made of all the Fal examples there. I wonder if records of tests, process drawings, anything of an engineering nature exists. There is a person over on the M14 Forum who started toolmaker training at H&R shortly after the T48 program was phased out. He might know something of what became of the paperwork at that facility since the 500 that were produced were toolroom samples. His name is SOCUM42 and the thread in mind is M14 Forum> Gun Forum> Foreign> "Fn fal". The thread is quite recent.

Visited "rediscov". Doesn't appear to be changed any from over 3 years ago.

In reference to an earlier post, the following links show the Fabrique Nationale example with the hook charging handle, serial number 37. For all I know, it may have been the only one. Seems doubtful there were many. Serial number 38 is an example of another prototype charging handle.

s/n 37
http://ww2.rediscov.com/springar/full/10029-SA.A.1.jpg

s/n 37 & 38
http://ww2.rediscov.com/springar/full/10031-SA.1.jpg

On the website exists pictures of some of the tracer mills and NC equipment. Cincinnate Telematics, MagneTRACE profiler, Fosdick Fosmatics, etc. But these date from the early 1960s where captions are provided.

[NHBandit]

Originally Posted by Raspeguy

Yes, which is why I expect this isn't going anywhere? I see two options with today's receivers. One, if the hook was to remain in the same relative position on the slide as the T48, you have the problem what to do with the plunger that keeps the charging handle in place. Second, if a facsimile hook was moved to a forward position to where the round knob is now it would be possible to incorporate the plunger and lug within the hook. There might be a problem?? with the cavities breaking out into the hook profile thereby requiring a wider hook or the use of at least an offset plunger. Seems the OP went AWOL on his thread. The hook has no appeal for me.

NHBandit, it would be nice if a definitive and high quality photo shoot could be made of all the Fal examples there. I wonder if records of tests, process drawings, anything of an engineering nature exists. There is a person over on the M14 Forum who started toolmaker training at H&R shortly after the T48 program was phased out. He might know something of what became of the paperwork at that facility since the 500 that were produced were toolroom samples. His name is SOCUM42 and the thread in mind is M14 Forum> Gun Forum> Foreign> "Fn fal". The thread is quite recent.

Visited "rediscov". Doesn't appear to be changed any from over 3 years ago.

In reference to an earlier post, the following links show the Fabrique Nationale example with the hook charging handle, serial number 37. For all I know, it may have been the only one. Seems doubtful there were many. Serial number 38 is an example of another prototype charging handle.

s/n 37
http://ww2.rediscov.com/springar/full/10029-SA.A.1.jpg

s/n 37 & 38
http://ww2.rediscov.com/springar/full/10031-SA.1.jpg

On the website exists pictures of some of the tracer mills and NC equipment. Cincinnate Telematics, MagneTRACE profiler, Fosdick Fosmatics, etc. But these date from the early 1960s where captions are provided.

Agreed that the hook type is actually not very common. Why guys keep wanting those for their T48 clones is beyond me unless it's just for the "cool" factor or because it's unique. The majority of T48 variations I've seen in person & in pictures use the normal knob type with the aluminum knob just like every G1 kit I've owned. Some were left bare Aluminum & some were painted black. I suppose if the demand for a "hook type" CH is there and mountainman wants to make up a batch, the old Tapco version would be the one to copy. At least those will work with the current "normal" uppers. The Armory Museum has changed alot since the first time I went there on a Cub Scout field trip in the 60s. Back in those days it was still run by the Army & IIRC they even sold brand new surplus 03 Springfield & trapdoor parts in the lobby in bins. I remember 1 scout campout where the scoutmaster brought a burlap bag of brand new stocks that had been cut in half to burn in the campfire.. I surely hope they were "seconds" at least. We also burned up a couple bags of wooden golf club heads he got from the Spalding factory. Growing up in that area of Mass was cool. Walking along the riverbank we would occasionally find rusty swords as well near the location of the old Ames Sword factory. For reference here is the T48 at the museum that's on public display. The total number of different variations they have on the second floor hidden from public view is a mystery but judging from the pics on "rediscov" there are ALOT.

[mountainman]

Detent is not the only problem. I have also come across problems with teh lug. Either way I have lowered teh detent area down to .302 and teh lug has to remain the same. Basically when I originally posted all I was intersted in was how it was made originally. Only a curious ?. I'll post teh pics when I am done. Clearly this is only for teh coolness factor and maybe that without any aluminum or delrin knobs this thing will be more durable. 1 solid pc of 4140, think of that. No rivet, no knob, no flimsy stem. One he!! of a pogo stick.

[mountainman]

Will be working on better prints. Is there anyone out there with an original or high quality reproduction. I want good blue prints of these so I can plot the curve out for machining. Marketplace WTS soon to follow

[NHBandit]

Nicely done. Finding an "original" will be next to impossible since I don't know of any T48s that got into civilian hands other than a handfull that were not cut up as "kits". And there would still be the issue of them not working with a normal upper reciever. Your best bet would be to locate an old Tapco style to copy but you might want to make sure they don't own that design. Not that Tapco cares one bit anymore about making FAL parts..

[SmokeEater2]

Originally Posted by NHBandit

Nicely done. Finding an "original" will be next to impossible since I don't know of any T48s that got into civilian hands other than a handfull that were not cut up as "kits". And there would still be the issue of them not working with a normal upper reciever. Your best bet would be to locate an old Tapco style to copy but you might want to make sure they don't own that design. Not that Tapco cares one bit anymore about making FAL parts..

Bandit, Are you talking about the fairly sharply hooked CH's from years ago? If so I've still got one of those on my STG.

[NHBandit]

Originally Posted by SmokeEater2

Bandit, Are you talking about the fairly sharply hooked CH's from years ago? If so I've still got one of those on my STG.

Yep. A real T48 hook type CH won't work on any FAL uppers that are in production today. Metric or Inch. The way they latch in the forward position is totally unlike anything else you've ever seen. Look here at T48 serial #37. Note how the CH rails on the upper have 2 raised "ramps" near the front. The pin sticking through the CH from side to side is the detent that acts as the forward latch mechanism. http://ww2.rediscov.com/springar/full/10029-SA.A.1.jpg This would be nearly impossible to duplicate without also modifying the reciever extensively. The early Tapco version like you have, I believe, is what mountainman is trying to duplicate.

[mountainman]

Only thing I am concerned with is getting an accurate curve on that hook. I was wondering if there were people out there willing to have their recvrs modified to fit a forward assist T48 CH.

Ya know have some slots EDM'ed in the recvr so little ramps can be press fit/silver soldered in there.

[Abominog]

Anybody ask Lee or EX1? If they don't have one, nobody does.

[mountainman]

Originally Posted by Abominog

Anybody ask Lee or EX1? If they don't have one, nobody does.

You know what, I completely forgot about those two. I think It was EX1 that sent me a belgian C clip to copy a very long time ago.

[jeffrey]

I still have 2 of hook type bought for compliance parts from Tapco back in their FAL parts heyday. Not using them now.

They got around the locking lug problem by simply using a screw .Highly recommend using locktite on that screw. Fit Imbel receivers just fine.

[mountainman]

Jeefrey, got close up pics? Anyone know if Tapco patterend teh hook off of an original, or if they didn't care about that?