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Thread: Springfield and A machinist

  1. #21
    Boolit Master



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    Nice 03 action for sale in S&S section. It's about 1/20th the cost of having one made.

    http://castboolits.gunloads.com/show...ngfield-action

  2. #22
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    There's a saying that really fit this thread. Speed costs money,,, how fast do you want to go?

    I have the drawings for the M14 receiver, all 7 pages of them. I couldn't make that part if my life depended on it.

    Mauser type receivers like Rugers are investment cast, ones that are machined form bar stock are very expensive

    The biggest problem with making any Mauser type bolt action receiver is cutting the bolt races. They generally are broached which requires first a broach that will cost a fortune and then a machine to stuff it thru the receiver,,, which will cost a bigger fortune. This is the reason why virtually all of the newest inexpensive bolt gun receivers are made out of round bar stock and are designed so that they don't have to have those complicated machining processes in them.

    Those actions could easily be made by many more machinists than any of the earlier designs.

    One last point,,, if you are planning on trying something like this I would suggest a copy of Jerry Kuhnhausen's book on Mauser Rifles simply because there is a bunch of little things about those actions that isn't immediately apparent. Lots of stuff going on in there, and all of it matters.

    Randy
    Last edited by W.R.Buchanan; 06-16-2017 at 02:17 PM.
    "It's not how well you do what you know how to do,,,It's how well you do what you DON'T know how to do!"
    www.buchananprecisionmachine.com

  3. #23
    Traditional actions, including the Springfield, started from a drop-forging. I'm not a professional anything in the gunsmithing or related fields, but I might have been one of the first people to say that we would one day be able to design things on 3D CAD programs, or buy them in digital form, and electrolytically erode or deposit them in quality steel at the press of a button. We have come and pretty close. But what beats me is why, with techniques such as repetition investment casting, EDM and CAD-CAM machining available, manufacturers are still so desperate to avoid complex shapes in steel.

    The trouble with investment casting is that the metal shrinks.. I have seen a figure of 4% from the wax model mentioned, and if we simply have a perfect wax receiver, it is going to shrink unevenly. I don't think a receiver with the bolt way and full-length locking-lug slots could be investment cast to sufficient straightness and consistency of diameter.

    I have always imagined that the round bolt way was drilled and reamed separately, and then each bolt lug way broached with something resembling a standard keyway broach. That wouldn't be cheap, but a lot cheaper than one which does the whole interior in one pass. I wonder if EDM could be done long enough to create those two slots from a round hole? This item, in my future projects collection so far, will one day be a thick sided small Martini action. It is in D2 air hardening steel, and the mortice is extremely accurate and sharp-cornered.


    Click image for larger version. 

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  4. #24
    Boolit Master
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    Manufacturers are not desperate to avoid complex shapes if it is truly necessary. But if it is not necessary it just represents added cost for nothing.

    Investment casting issues 1. The wax has to be injected into a mold. Upon cooling after being removed from the mold the wax warps, twists due to differential shrinkage. More sophisticated foundries will use a rack or form to help control distortion of the wax before it is dipped into the shell slurry. Then of course the wax is burned out of the shell. Remember the shell cavity was made with a warped piece of wax before it was poured full of molten steel. Then the steel warps and twists and shrinks as it cools. So you have 2 different distortion factors in the cast steel. One from the wax and one from the molten steel. Some companies "straighten" the castings with press operations. Some companies have guys with big forearms and a BF hammer to beat the heXX out of the castings in order to straighten them.

    EDM is used is many or most industries as a tool and die making process. I worked in an industry where wire EDM was an actual production process. One of our suppliers in Ohio had 30 wire EDMs slicing parts but they were parts for surgical instruments. Those parts were much more expensive and much more profitable than mere gun parts. After all you are paying for the instruments through your insurance premiums. The insurance companies don't care how much they cost because they can just raise your premium cost.

    Multiaxis DNC machining using CAD-CAM data off a network is capable of sculpting parts from a block of steel with very little hard tooling. However those machines run about a quarter million and up. When those machines are in operation the manufacturer will do everything possible to make the most money. That means semiconductor, medical or other very high cost products.

    One of the ways you deal with warped and twisted castings is leave extra stock on the part and then finish machine more of the part or even all surfaces. You have added costs back into the product by doing that but you can control the part geometry and surface texture more easily. But will the customer pay for it?

    There are already receivers used in benchrest and other custom rifle actions that are wire EDM cut to make the bolt lug raceways. But you know they are expensive. You also get a hard recast layer on the surface of the steel. Some parts can be used as is. For highly stressed orthopedic implants we had to remove the hard recast layer.

    Nearly 50 decades ago I worked at a contractor that manufactured jet engine and helicopter transmission parts. One of the jobs that green weenies did was run their broach.
    This was a 20 ton horizontal broach made by a company named Colonial.
    It looked like this one Click image for larger version. 

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    The broaches were any where from 18" long to 4 feet long. Those that I ran cut internal splines and gear teeth into transmission parts. Small parts could be stacked 4 at a time for broaching. Larger parts were broached in pairs or singles. One pull and return cycle for the broach was about 1.5 minutes. So it is a cheap process other than the cost of the new broaches and keeping them sharp. It is cheap but only if the volume is high.


    Quote Originally Posted by Ballistics in Scotland View Post
    Traditional actions, including the Springfield, started from a drop-forging. I'm not a professional anything in the gunsmithing or related fields, but I might have been one of the first people to say that we would one day be able to design things on 3D CAD programs, or buy them in digital form, and electrolytically erode or deposit them in quality steel at the press of a button. We have come and pretty close. But what beats me is why, with techniques such as repetition investment casting, EDM and CAD-CAM machining available, manufacturers are still so desperate to avoid complex shapes in steel.

    The trouble with investment casting is that the metal shrinks.. I have seen a figure of 4% from the wax model mentioned, and if we simply have a perfect wax receiver, it is going to shrink unevenly. I don't think a receiver with the bolt way and full-length locking-lug slots could be investment cast to sufficient straightness and consistency of diameter.

    I have always imagined that the round bolt way was drilled and reamed separately, and then each bolt lug way broached with something resembling a standard keyway broach. That wouldn't be cheap, but a lot cheaper than one which does the whole interior in one pass. I wonder if EDM could be done long enough to create those two slots from a round hole? This item, in my future projects collection so far, will one day be a thick sided small Martini action. It is in D2 air hardening steel, and the mortice is extremely accurate and sharp-cornered.


    Click image for larger version. 

Name:	Cadet receiver.jpg 
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    EDG

  5. #25
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    Quote Originally Posted by EDG View Post
    Manufacturers are not desperate to avoid complex shapes if it is truly necessary. But if it is not necessary it just represents added cost for nothing.

    Investment casting issues 1. The wax has to be injected into a mold. Upon cooling after being removed from the mold the wax warps, twists due to differential shrinkage. More sophisticated foundries will use a rack or form to help control distortion of the wax before it is dipped into the shell slurry. Then of course the wax is burned out of the shell. Remember the shell cavity was made with a warped piece of wax before it was poured full of molten steel. Then the steel warps and twists and shrinks as it cools. So you have 2 different distortion factors in the cast steel. One from the wax and one from the molten steel. Some companies "straighten" the castings with press operations. Some companies have guys with big forearms and a BF hammer to beat the heXX out of the castings in order to straighten them.

    Nearly 50 decades ago I worked at a contractor that manufactured jet engine and helicopter transmission parts.
    Your first statement is 100% correct.

    Investment Casting trueness is mostly contingent on the actual design of the part. A 2" cube will NOT be distorted in any way. Long skinny parts probably will be. I have a shop in Port Hueneme that makes the Receivers for M134 Mini guns. They are very complex and only receive a very small amount of machining after they cool. These guys are very good!

    50 Decades is along time to be working.

    Randy
    "It's not how well you do what you know how to do,,,It's how well you do what you DON'T know how to do!"
    www.buchananprecisionmachine.com

  6. #26
    Boolit Master
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    The investment castings I worked with always warped and they always needed straightening. That included A356 aluminum, 6AL4V Titanium and ASTM F 75 which is a cobalt chrome alloy similar to Stellite 21.

    Quote Originally Posted by W.R.Buchanan View Post
    Your first statement is 100% correct.

    Investment Casting trueness is mostly contingent on the actual design of the part. A 2" cube will NOT be distorted in any way. Long skinny parts probably will be. I have a shop in Port Hueneme that makes the Receivers for M134 Mini guns. They are very complex and only receive a very small amount of machining after they cool. These guys are very good!

    50 Decades is along time to be working.

    Randy
    Last edited by EDG; 06-18-2017 at 11:19 PM.
    EDG

  7. #27
    Boolit Master woodbutcher's Avatar
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    Hi minuteshaver.Maybe one day you will luck out like a friend of mine did in about 1964.He bought 6 O3A3 never touched actions for $200.00 bucks out the door.
    Good luck.Have fun.Be safe.
    Leo
    People never lie so much as after a hunt,during a war,or before an election.
    Otto von Bismarck

  8. #28
    Boolit Master

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    Almost 40 years ago I was helping a shop build 50 BMG single shot bolt action rifles. The first ones were investment cast out of 4140. We had to anneal them twice to get them soft enough to straiten out with a hydraulic press. The actions were 2&1/4" diameter and 13" long. Bolt was 1&5/16" diameter with a section turned down behind the four locking lugs, Like a Weatherby. All the trouble we had with the castings the boss finally went to solid bar stock and machined the whole action.
    John Taylor, Taylor Machine, gunsmith

  9. #29
    Quote Originally Posted by W.R.Buchanan View Post
    Your first statement is 100% correct.

    Investment Casting trueness is mostly contingent on the actual design of the part. A 2" cube will NOT be distorted in any way. Long skinny parts probably will be. I have a shop in Port Hueneme that makes the Receivers for M134 Mini guns. They are very complex and only receive a very small amount of machining after they cool. These guys are very good!

    50 Decades is along time to be working.

    Randy
    They are complex, but perhaps more symmetrical than some. Cubes are totally so, and may indeed experience no appreciable shape distortion, although I wouldn't have excluded possibly negligible convexity of the surfaces. But it is a physical impossibility to investment cast 2in. steel from 2in. wax. You would have to start larger.

    I used to know John Slough of London who made a stainless adaptation of the CZ pistol, and, oddly enough, cast-iron replica garrison carriages for some of the cannon in Gibraltar. I forget the shrinkage rate from wax to steel he mentioned, but it was easily enough to cause distortion if one side of a bolt-action ejection port and magazine was bulkier than the other. I am not surprised many have gone over to machining from the solid. I had to investment cast such a receiver, I think drilling the bolt way or milling down one of two identical sides would work best, and that cuts the benefits of the system.

  10. #30
    Boolit Man TRX's Avatar
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    The book has all the required drawings of the tools and setups. The problem is, most of the operations depend on horizontal mills, and almost all of the cutters are custom-made. Back then, every shop had at least one toolmaker who did nothing but make, heat treat, and resharpen custom cutters.

    The design of the Springfield is based on that sort of tooling. You could duplicate it with a modern CNC vertical mill, but it would take a *lot* of tool passes to approximate the shapes of the hollow-curved horizontal mill's cutters, and you'd probably still need some custom cutters for odd shapes.

    You can pick up an old horizontal mill for cheap enough. Cutter grinding machinery can be found on eBay and on used machinery sites, but you'd also need most of the accessories, which were generally stripped when the machines were sold. And you'd need a heat treat oven and quenching materials.

    Back when the Springfield was designed, it was intended that it be hard to make, more or less as a propaganda measure. Colvin commented that many of the features of the bolt and receiver seemed to serve no purpose other than to be a hassle to machinists. In any case, manufacture of the Springfield was so tedious that the US Government decided to concentrate war production efforts on building a variant of the British Pattern 14 Enfield adapted to the US .30-06 cartridge. The Enfield was not just a superior design, but vastly easier to make. The Enfield was designed to be made with the same type of equipment as the Springfield, but it wasn't nearly so ornately complex.

    There's still a ton of useful information in "US Rifles & Machine Guns" if you spend some time studying it. Materials, heat treat, locking lug design, opening and closing cam angles, and so forth. You just don't find much of that sort of detail on rifle design commonly available.

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BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
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