From: [g--y] at [ke4zv.atl.ga.us] (Gary Coffman) Newsgroups: rec.guns Subject: Re: Making Magazines in a Machine Shop Date: 12 May 1994 11:44:55 -0400 In article <2qgpai$[3--0] at [senator-bedfellow.MIT.EDU]> [s--b--k] at [athena.mit.edu] (The Rifleman) writes: #I would like to start a new thread for those interested, for informational #purposes only of course, in how magazines might be manufactured by #an individual in a machine shop. # #What materials are necessary? I would guess: # #(1) Spring steel of approx. 1/16" diameter, approx. 1-2 yards per mag. Annealed music wire, available at any hobby shop. Wind to spec and heat treat in homemade furnace. You can make a suitable furnace from some firebrick, a 20 lb gas grill propane bottle, and a homemade burner. Or you can get a ready made unit (intended for hobby casting) from Kansas City Specialties for a couple hundred dollars. A good smith can judge temperature by color, but pyro cones are available cheaply for use in casting furnaces. Heat until they slump, and you're at the right temperature. Quench in brine or oil depending on the desired temper. #(2) Sheet metal, ordinary or stainless steel, approx 1 square foot per mag. Available at any metals shop, or salvage from old refrigerators or autos. #(3) small bar of steel out of which follower may be fashioned, or # plastic mold out of which to fashion follower. What types of # plastics should be used and where are they available? Injection molded nylon would work, but it's a pain to work with. Better is to just form the follower out of sheet metal. Cold forming over the horn of the anvil should work well enough. #(4) If ordinary rather than stainless steel in (2), a cold bluing kit, # probably available from Brownell's. Or ordinary spray paint. #What tools are necessary? I would guess: # #(1) Precision calipers and measuring devices. Calipers would be useful, but ordinary transfer calipers are sufficient. You'd make a wooden or steel pattern block as a guide and just transfer the measurements off of it. #(2) Scratch awl. Useful for layout, as well as some machinist's blue. #(3) sheet metal punch for punching witness holes in mag, and or lettering If you want to get fancy. #(4) sheet metal folder--large device for folding sheet metal according to # specified dimensions (How much would this device cost?) Little Giant sheetmetal brake, about $100 from Morthern Handyman. You can make your own from a couple of pieces of 2x2x1/8 angle iron and a couple of C clamps though. (Sheetmetal work isn't rocket science.) #(5) a vice or specialized tool for bending the spring steel sharply into # a single, square helix so it can be used as the magazine spring. No, you'd form the annealed music wire quite easily with ordinary pliers around a steel mandrel and then heat treat as above. (Note, you *can* wind springs from hard music wire, but they won't be as strong, and it's a pain to do. Spring tools, actually just a specially shaped pair of pliers, are available from many sources including Brookstone, about $15.) #(6) Protective equipment--respirator, fan, etc. necessary for using # cold bluing kit. Necessary for *hot* bluing processes, but not for cold blue. #*Heat Treatment* # #What additional heat treatment would the feed lips require? What temperatures #are required? Would a stoked blacksmith's furnace with a belows be #capable of generating this kind of heat? How must the heat treatment #be applied? Ordinary sheetmetal cannot be hardened by heat treatment, too low a carbon content. Magazines aren't normally heat treated, the sheetmetal is thick enough to retain it's shape against spring pressure without it. (A blacksmith's forge can melt steel, it's considerably hotter than would be needed for heat treatment. For spring steels, heating to a light straw color is sufficient, about 1800 degrees F.) #*Recursive Error Analysis* # #During the first run, magazines would be made in a set differing several #1/100's of an inch in each crucial dimension. (Both dimensions other than #up and down the magazine.) When finished they would be tested for #ease of fit, tightness of locking in place, and ease of ejection. The #best set of dimensions would be chosen. Next, the follower design would #be varied once the dimensions of the mag were settled upon to maximize #flawless feeding of factory ammo. # #Recurse as necessary to approach ideal specs. Start with a wooden pattern block. Whittle it roughly to shape then sand and fit until it locks in place with the proper fit. Then transfer it's dimensions to the sheetmetal. Copy the lips and follower from a crippled mag. Form with a hammer and cold rolled rods as mandrels. Should take all of a half an hour to produce your first working magazine. After that, production rates would increase rapidly to about one every 5 minutes or so. (Sheetmetal work *really* isn't rocket science.) Gary -- Gary Coffman KE4ZV | You make it, | gatech!wa4mei!ke4zv!gary Destructive Testing Systems | we break it. | uunet!rsiatl!ke4zv!gary 534 Shannon Way | Guaranteed! | emory!kd4nc!ke4zv!gary Lawrenceville, GA 30244 | |