General News and Events
On the August 17th meeting we had ten members and two guests attending. A vote was taken amending the bylaws to allow the use of a personal checking account for the club treasury. J.D. Wise was elected as our new secretary. Alan showed us a wobble center he built. George Edwards gave a presentation on a Ajax (Tiny Power) steam engine kit he built. George discussed many of the trials and tribulations he went through in building the engine. I think everyone would agree that he did a fine job. J.D. Wise showed us a collet adapter he made for his 9x20 lathe. This was a very interesting device that used standard spring collets to hold material. Good work J.D.
Of Special Interest or HELP!
As always, we are desperately needing articles to publish in this Journal. ( I am running out of ideas.) If you would like to submit an article, idea, or photograph there are several ways this can be done. The best way to submit an article in machine readable form. A plain text file is the easiest to work with. It can be placed on a floppy and mailed to my home, or, attached to an Email and sent via the Internet. Articles and other ideas can also be faxed to my office at (713) 251-3860. This is a Spring number, and will be a toll call for most of you. If you have any photographs of projects, I would like to try to publish them here. If you have a scanner, send me the scanned image file in JPG or TIFF format over the Internet or via US mail. If you don't have a scanner, send the photo in the mail, or hand it to me at a meeting. I don't think the FAX will work well enough. If you don't have a usable photo of your project, give me a call and we'll shoot it on 4x5 Poloroid and make it look pretty. Also, mechanical drawings in DXF, WMF, CGM, or AutoCAD DWG are easy to put into the newsletter.
Putting the Shop to Work
We have a very unique hobby. This is the only hobby I can think of that can provide so much support for other hobbies and interests. I've been involved in many pastimes over the years, but it seems that I always end-up relying on the skills I developed in metalworking to get me out of a jam. In the last few years I have trued and barreled actions, made scope rings, and built rifle and pistol rests for my shooting activities. I have built various antenna mounts and chassis for amateur radio. I am building an 8x10 camera from scratch, and the accessories to go along with it. Also print washers and other darkroom apparatus. For other people, I have built wood-working equipment; airplane, race car, show car, and boat parts. Repaired numerous pieces of lawn equipment, mostly edger shafts for extinct brands of edgers. And pool parts, lots of strange fittings for repairing broken valves and pumps. At Christmas a couple of years ago, I was somewhat of a local hero for fabricating fittings for copper pipe. Many pipes in the neighborhood had burst, and the hardware suppliers were all out of fittings. We were able to get the water running in several houses much sooner because of a little brass bar stock and a lathe. In short, your talents and equipment can be a valuable resource to your community. Another interesting thing about this hobby is that it is very easy to make it pay for itself. Unlike wood-working and other craft activities, there is a demand for your products outside of the consumer/end-user market. Once you become fairly competent in metal-working, start looking for small jobs that will improve you skills and pay for some new tooling. To set-up a small business is simple. It is a good idea to apply for an assumed name for your enterprise. This is done at a courthouse annex. It costs a few bucks, but gives you a more professional image. Next visit the comptroller's office. Explain what type of work you plan to do. Since the volume will be so low, they will probally wave any deposits, and give you a Sales Tax I.D. Number. It is necessary to have a tax number because you are required to collect sale tax on most sales. It does allow you to purchase tooling and material that go into your finished product tax free. The state now also exempts production equipment from sales tax. Check it out before you buy a lathe or mill. Get some business cards, and your off to the races.
Finding customers is not as hard as you would imagine. Since your over head is low, you don't need to spend a lot of effort marketing. If you run across a job that you would like to do, then take it. Otherwise, keep working on your own projects and sharpen your skills.
The home shop has a few unique traits that make it very competitive in a couple of areas. Most machine shops need volume production to make things pay well. For them, set-up, tear-down, and clean-up, cost money. Therefore, it is difficult for even small full-time shops to do one piece jobs for a reasonable price. The biggest advantage you have is the fact that most shops don't work on week-ends. If something comes up on Friday afternoon, it can be a very expensive proposition to get it done be Monday morning. Also, since you will not keep a backlog of work, you can get to the job right away. Many times a quick job, such as a special bushing or shaft, can be delivered the same day as it is requested, this makes customers very happy.
Customers can be found in all areas of commerce. Take business cards and brochures to area merchants and shops. Almost any business that manufactures a product may need your help at one time or another. Donut shops, dry cleaners, lawnmower shops, car repair shops, even restaurants and bars have equipment that breaks from time to time. Do them a favor, drop off your card, maybe you can help get them out of a jam. Don't be afraid to turn down a job if it is beyond your skill level, or it appears that it may result in an unsafe condition. ( Don't take a job cutting the guards off a piece of equipment. ) Start by taking the type of job where you make a part from a piece of stock. If you mess it up, you can keep working on it until it is right. Don't take a job modifying specialty pistons for a Porsche until you are sure you can accomplish the job and not destroy the workpiece. And last but not least, don't be afraid to charge for your services. Good-luck, and start making all that cast iron pay it's way.
Properties of Metals for Use in the Home Shop
The following is a list of some of the common metals used in the home shop. Much of the information comes from experience, and a Ducommun Metals Stock List catalog I got back in 1974. They may still be available, I'm not sure.
Common Steels -
Mild Steel, This usually refers to steels with carbon contents lower then 0.3%. Steels with carbon content in this range cannot be heat treated to improve hardness. They can be case hardened, however, for greater strength. Mild Steel is available as hot rolled angle, channel, flats, and round bar. Hot rolled steel has a dark crust, is not as dimensionally accurate as cold rolled, but, has lower internal stress. Cold rolled steel is available as rounds, tube, and flats. Trident sells 1018 ( 0.18% carbon), this steel is very good for high precision work because it has a very fine grain and machines easy. These steel will weld, braze, and solder very well. 12L14, This is a mild steel designed for use with screw machines. It contains about 0.15 to 0.35% lead to aid in machineability. 12L14 is only available in rounds and hexagons. This material is very easy to machine and produces a beautiful finish.
4130 and 4140 are both chrome-moly alloys with high strength. 4130 is easy to machine and weld but can only be hardened to about RC35. 4140 contains more carbon and can be hardened to about RC50. Both are most commonly seen as seamless tubing and is used for race car frames and aircraft. O1 and W1 are high carbon tool steels that can be hardened to about RC60. Drill rod is available as either O1 or W1, O1 being designed for use with oil quenching, W1 with water. Both steels contain 1% carbon which makes them somewhat difficult to machine, but allows for the high degree of hardening.
Common Stainless Steels
Stainless steels are generally grouped into two types. The 300 series stainless is alloyed with Chromium and Nickel. The 300 series is non-magnetic and can not be heat treated to increase hardness. The 400 series is alloyed with Chromium. Stainless steel in this group in usually magnetic, and can be heat treated. All stainless steels are subject to work-harding. When cutting stainless it is important to use slow speeds and high cutting pressure to prevent the tool "sliding" across the surface of the work-piece and work-hardening the stainless. It is also important to use a centerpunch with a sharp tip when center-punching stainless steel.
303 Stainless, This is a SS available as rounds, hexes, or rectangles. It is designed for screw machine use and therefore, is free machining. 303 is the best SS to use for general machined parts made of stainless.
304 Stainless, Most often found as tubes and sheet, this stainless is harder to work than 303 but welds nicely.
316 Stainless, This is the most corrosion resistant SS. It is also difficult to machine because it acts "gummy" yet work-hardens in an instant. Available as sheet, tubes, and solids.
416 Stainless, This stainless machines quite well and is heat treatable to about RC35.
440C Stainless, Tough to machine but very strong. This is the alloy used by most gun makers.
Aluminum comes in a variety of alloys that are all optimized for specific applications. There is really no such thing as "aircraft" aluminum. Almost all aluminum alloys find their way aboard aircraft in one form or another. I am outlining on those alloys that are of interest to home machinists.
2024 - This is a high priced alloy designed for high strength solid parts. It does not hold up well to corrosion. It can not be welded with normal fusion methods, and does not anodize cleanly.
3003 - This is almost always found in sheet form. It is very easy to bend and shape into complex forms. Although, like most non-ferrous metals, 3003 work hardens, it does so relatively slowly. This makes it ideal for shaping complex curves, etc. 3003 welds and anodizes very well. It is soft and gummy when machining.
5052 - This is a sheet material that is a good bit stronger than 3003, but still can be bent with zero-radius bends to 1/16 thick. It also welds and anodizes quite well. It is a little gummy to machine.
6061 - Probably the most common alloy for solid parts. This alloy is strong yet easy to machine. Usually found as 6061-T6 or T651 heat treated. It is available in all common forms. It welds easy and anodizes well. 6061 is available in sheet and plate. Since it is harder than the 3000 of 5000 series, it is difficult to bend without fracturing.
6063 - Designed primarily for architectural extrusions, 6063 welds and anodizes very well. It is a little gummy to machine. A rule-of-thumb is: Angle aluminum with a radius web on the inside corner is probably 6061, if the inside corner is square, then it is 6063.
7075 - This alloy is usually found in sheet form. It is a very high strength material but suffers from many of the same problems 2024 has. Non-weldable, anodizes poorly, and has poor corrosion resistance. On aircraft skin, 7075 is usually clad with pure aluminum to improve appearance and corrosion resistance.
Copper - Pure copper is very difficult to machine because it is soft and gummy. All copper alloys solder nicely.
Brass - Most brass is about 70% copper and 30% zinc. There are variations, but most any brass machines beautifully. Some free machining brasses have 2 or 3% lead added for lubrication.
Bronze - The terms brass and bronze seem to be swapped around a bit. The general rule is; if it contains copper, zinc, and tin, it is a bronze. The tin in place of zinc improves corrosion resistance considerably. Brass tends the lose it's zinc content, and turn into copper sponge, when placed in salt water for long periods. Even .075% tin will do much to improve the corrosion resistance.
HSMC Member Library
There are several ways for the Club to be of benefit to members. We have already had meetings where ideas are shared and advice given. Another program that may be helpful, is the sharing of publications between members. This is what I propose: All members wishing to participate would generate a list of the books and other publications that they would be willing to lend to other members. The list could be consolidated and redistributed to the membership. If a person wished to borrow a certain item, he would contact the owner and work out the details. Owners should keep a list of the items that have been borrowed and the individual that he lent the item to. I know I have several books published in the very early 70's in England that would be of interest to other members. I'm sure that these would be very hard to find on a store shelf today. A few titles are Using the Small Lathe by L.C. Mason, The Beginners Guide to the Lathe by Percival Marshal, and The Novice's Workshop by "Duplex". I also have Home Shop Machinist for the last twelve years. If you would like to get involved with this program bring a list of the items you would like to make available to the next meeting.