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Quote: The question wasn't whether or not it would be cheaper, it was whether or not the part could be machined, and or it is ever done. The answer is yes, to a point. As Fjold has pointed out with some intersesting techinicalities, while the contour section of impellers, which I've had the misfortune of working with out of aluminum sand castings, not titanium are feasible, the turbine blades that have internal cooling would not permit a part of that nature to be machined. The important part that most people forget about whether a part can be machined, or it must be casted is the fact that 9 times out of 10 the mold must be machined to near net shape, only to finished off with a variety of different methods, namely EDM. Nevertheless, once you see what the potential a CNC machining center has, and what it can accomplish, your mind is usually your biggest limitation. | |||
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Quote: Their receivers were being forged in Rhode Island, but that company has since went out of business and they've moved their operation to another facility. The 94 receiver is still being forged and machined and that goes for the Marlin receivers as well. | |||
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Quote:Quote: I was the purchasing manager of a large mfg co in CT from the mid 1960's thru the mid 1980's. I bought castings, forgings and most other forms of metal. For instance some of my suppliers were Sturm Rugers Pine Tree facility and Thompson Centers foundry as well. Another type of casting that we bought were sand castings that used ductile iron along with alloy steel, aluminum and magnesium sand castings. One of these ductile iron foundries is quite local to our plant and I had the opportunity to visit the plant many times. I even took a course on metallurgy there given by the foundries metallurgist. During some of those plant visits I saw drums and drums of ductile iron sand castings of the M 94 Winchester receivers. As I said I brought a gold plated one home with me. Perhaps the ductile iron castings were not a production item. But I think I am right as why else would they have made a finished receiver out of them? I got mine out of the returned scrap barrel. We used the ductile iron castings to make tools. One example would be the base, handle and trunnion for a manual steel strapping tensioning tool. These castings were purchased in the annealed condition in ductile iron and not heat treated afterwards. I don't know what grade of ducile iron Winchester used but I was told it was ductile iron by the foundrys metallurgist. For tools that used HT (high tensile) strapping alloy steel sand castings were used for the base of the tool. The company that I worked at for many decades had a laboratory there with 44 employees! I grew up in that neighborhood and used to play sandlot football where the new lab was built. | |||
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Their receivers were being forged in Rhode Island, but that company has since went out of business and they've moved their operation to another facility. The 94 receiver is still being forged and machined and that goes for the Marlin receivers as well. Maybe now, but my 1967 M94 was probably cast, either that or the machining was something awful, the channel for the locking bolt is way over size for the bolt, and the trigger assembly underneath fairly rattles. . . Come to think of it. . . it's really bad for a casting, anyway. John L. | |||
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JAL, A ductile iron sand casting would have at least 3 mm oversize for machining stock removal. Put another way, your M94 is simply sloppy machining. The comments about red bluing my be true then as my M94 (circa 1970) is red on almost all the internal surfaces, but a nice deep high luster blue on the external. Any idea why that is? The machined surfaces of my M94 still appear to be steel to me not ductile iron, though. There is a visible difference between the two materials. Thanks for the information it is interesting. ASS_CLOWN | |||
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Their machining lacks a lot to be desired, but that's mainly due to the fact that they're still using equipment that was state-of-art in 1950. Rhode Island Tool Company had barrels of forgings for Winchester and Marlin, not to mention all of Starret's forgings were done there, as well as Berretta's slides for the Model 92's. Their shop was built during the Civil War, and to say it was a step back in time was an understatement. Quite an impressive facility to say the least. There machines had been retrofited many times, and had originally been ran with leather belts, then steam, and finally hydraulics. The general manager had said that under the big hammer forge they had 3 bundles of telephone poles stacked on end, 24 to the bundle, directly under the press. Within those bundles was rock and concrete. This all sat on top of a granite mountain side, so ridgitity was quite impressive. This was not a place to enter without hearing protection. About two hits from the hammer and your ears were ringing like you'd been shooting a 2" Smith&Wesson 357 with magnaporting. Not the place you'd want to be with a hangover on Monday.  | |||
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Matt, I have not been to that RI facility but I have been in Storts in Mass and Cape Ann Tool on the Mass. coast. The bunch that ran and sold for Cape Ann were as tough a bunch of characters as one could imagine. These guys should have been used for the fight in Giant. Your description of the inside of a forge shop is quite on. The ground shakes under your feet, it's dark in there with smoke everywhere. Your shouting at the person with you to try to understand. The men running those hammers must really take a beating with the red hot steel flying all over the place. | |||
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Quote: Yeah, I'm sure it must do wonders for the arrangement of internal organs. When you can feel the ground shake 4 city blocks away.......that's a pounding. | |||
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Savage99, The Kimber 84 and 8400 bolts are not cast. They are machined from bar stock as well as the bolt handle. The handle is then screwed into the bolt body. Headache | |||
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Matt, Good to hear from you. (Thanks for your vote of confidence!) I do not know the exact reasons behind the red effect on bluing investment parts, but every time we had a problem with "red" parts the metalurgist used to tell me that it was because of the silicon. I also believe that it required the bluing tank temperatures to be held more closely. ASS_CLOWN, I appologize if I do not get my terminoligy correct Also spelling . I believe it is the grain structure and not the molecular structure.I believe investment casting has a course cell (grain) structure (porosity) as compaired to bar stock. Yes bar stock is cast, but it is then eather hot rolled or cold rolled to shape which changes its cell (grain) structure. You are correct that many of the parts in an airplane are investment cast. These parts are usually very complex shapes and would be very difficult to machine. Usually they are cast one piece at a time. They are x-rayed to check for porosity. The rejection rate can be high driving up the cost of the finished accepted parts. They are also designed to compensate for the cast material strength. Have a great day, Headache | |||
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Savage 99, that reminds me of the time I was on Cape Ann with a group of artists .They were complaining about the noise and vibration. I said that was from the Cape Ann Tool Works I should have visited them. | |||
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Headache, Quote: NO apology necessary! It was mete not I that got his shorts in a bunch about your terminology.  Quote: There is nothing that can be done about the grain structure then? It is set in stone? Quote: Is there NOTHING that can be done to minimize or even eliminate porosity in the casting? Quote: Cannot the firearm components be designed likewise? Do you know if USRAC and/or Marlin use ductile iron for the receivers in their lever action rifles? Also, could you shed some light on the effects of grain flow for me? Seems a casting would possess better grain flow than a billet (bar stock) part would. Is this a good thing or a bad thing? Thanks for all the help on this one. ASS_CLOWN | |||
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ASS_CLOWN, You ask many good questions. With my limited experience I will stick my neck out again. (I hope someone with more investment casting experience will chime in!!) 1. As far as grain structure is concerned I don't think anything is set in stone. I think there is a process called 'hipping' (My old head is trying) where pressure is applied while the metal is still molten to compress the grain structure. (This is costly) 2. There are many things done to try and eliminate porosity. How/where you gate (feed) the material. Placement of sprews (pockets) to give the air some place to go which you would cut off later. Design of part as far as wall thickness variations and sharp corners which interfears with the flow of the material. 3. Firearms components can be designed for investment casting (and have been - look at Ruger) but, to maintain a high degree of material integrity is costly. It has been my experience that the ammount of rejects due to internal porosity and the cost to rework parts due to surface porosity that shows up during finishing is high. Ruger (Pinetree Casting) does a great job in controling their process and they get good results. I do not know if anyone uses investment cast bolts and receivers for the large 'African' calibers. 4. I believe USRAC and Marlin use forgings of high quality heat treatable steel somewhere in the 4140 range. 5. Grain flow helps, but it works in conjunction with cell structure. Even though you are cutting into the grain flow, with bar stock the cell structure is still stronger. When using a forging you have bent the grain structure while maintaining a tight cell structure. This will increase the strenght of the finished part. My limited knowledge will get me in trouble. Once again, have a great day, Headache | |||
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If you heat treat the steel you will change the grain size.The as cast grain size will vary according to cooling rate , cooling rate [this is also dependent on thickness ], alloy.Proper casting techniques will minimize or eliminate porosity.Investment casting in itself is expensive . It's competitive if it eliminates some machining operations .Proper investment casting then includes designing it from the beginning to be cast.The grain flow benefit is with forgings , not so much with bar stock.But there are many variables so sometimes there is benefit sometimes none. | |||
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Nice to see you made it back Pete. These guys have been chomping at the bit for some more info. I figured you could shed some light on the subject. By the way, have you talked to Bill lately?? I've sent him a few emails about replacing his One-Piece Bottom Metal with one of the newer models, but haven't heard anything back from him for a long time. Are you going to be making it to the shot show this year? If so, we should meet up and share some ideas over an appropriate beverage. | |||
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I have to agree with Mete. If a part is designed as an investment part and it is designed correctly, then there should be no reason to use said part. Ruger has perfected the casting process in the firearm industry, but only with many dollars thrown at the process, hence they have learned about the process. Having said that and all things considered I would use investment parts without hesitation. | |||
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The Accurate Reloading Forums THE ACCURATE RELOADING.COM FORUMS Guns, Politics, Gunsmithing & Reloading Gunsmithing Re: Investment cast recievers?
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