ComputerHunter.org

 

Repairing Your Own Machine Components


Many industrial concerns have workshops of their own. For the repair of worn shafts, the lathe machine is excellent. Keyway slots can be machined by using a milling machine, while a shaping machine can do machining of large flat areas. A drilling machine does drilling of holes.

A skilled Maintenance Engineer should know how to use all these machines in order to make his own repairs in a safe manner. Very often he has to supervise machinists. The information below should be useful for that purpose.

Lathe Machine

The lathe machine uses a single-point-cutting tool for a variety of turning, facing, and drilling jobs. Excess metal is removed by rotating the work piece over the fixed cutting tool to form straight or tapered cylindrical shapes, grooves, shoulders and screw threads. It can also be used for facing flat surfaces on the ends of cylindrical parts.

The work piece is clamped onto a horizontal rotating shaft by a 3-jaw or 4-jaw chuck. The latter chuck can be used to cut off-centered cylinders. The rotating horizontal spindle to which the chuck is attached is usually driven at speeds that can be varied.

The cutting tool is fixed onto a tool rest and manipulated by hand. It can also be power driven on straight paths parallel or perpendicular to the work axis. This is useful for screw cutting.

Internal turning known as boring results in the enlargement of an already existing hole. The holes are more accurate in roundness, concentricity, and parallelism than drilled holes. A hole is bored with a single-point-cutting tool that feeds along the inside of the work piece.

Shaping Machine

The shaping machine is used to machine flat surfaces, grooves, shoulders, T-slots, and angular surfaces with single-point tools. The cutting tool on the shaper oscillates, cutting on the forward stroke, with the work piece feeding automatically toward the tool during each return stroke.

Drilling Machine

The drilling machine is used to cut holes in metal with a twist drill. By changing the cutting tool, they can be used to do reaming, boring, counter boring, countersinking, and threading.

Milling Machine

The milling machine uses a rotating cutting tool to cut flat surfaces, grooves, and shoulders, inclined surfaces, dovetails, and T-slots. Cutters of many shapes are changed to cut different grooves.

Cutting Tools

Metal-cutting tools are classified as single point or multiple point. The lathe and shaping machine use single point cutting tool while the milling and drilling machines use multiple-point-cutting tools.

Metal is cut either by moving the work piece like in the lathe or by moving the tool like in the shaping machine, drilling or milling machine. Clearance angles must be provided to prevent the tool surface below the cutting edge from rubbing against the work piece. Rake angles are often provided on cutting tools to cause a wedging action in the formation of chips and to reduce friction and heat.

Tool Materials

In order to remove chips from a work piece, a cutting tool must be harder than the work piece and must maintain a cutting edge at the temperature produced by the friction of the cutting action.

Carbon Steel

Carbon steel tools even though comparatively inexpensive tend to lose cutting ability at temperatures around 400 degree F (205 degree C).

High-Speed Steel

High-speed steel, containing 18 percent tungsten, 4 percent chromium, 1 percent vanadium, and only 0.5 to 0.8 percent carbon, permits the operation of tools twice or three times the speeds allowable with carbon steel

Cast Alloys

Cast-alloy cutting-tool materials containing cobalt, chromium, and tungsten are effective in cutting cast iron and retaining their cutting ability even when red hot.

Cemented Tungsten Carbide

The hardness of Tungsten Carbide approaches that of a diamond. Tungsten carbide tools can be operated at cutting speeds many times higher than those used with high-speed steel.

Oxides

Ceramic, or oxide, tool tips consist primarily of fine aluminum oxide grains, which are bonded together. These are very hard.

Cutting fluids

An overheated tool can become blunt and soft very fast. Therefore very often, cooling fluids cools the cutting points of the tool. This serves to lubricate and cool.

Water is an excellent cooling medium, but it corrodes ferrous materials. Sulfurized mineral oil is one of the most popular coolants as it can both cool as well as lubricate. The sulfur prevents chips from the work from melting on to the tip of the tool.

Move Closer To Financial Freedom!

Best selling author of the megahits Nothing Down and Creating Wealth, shares the secret of success. Generate wealth and profit over $100,000 a year - on a part time basis, working from your home, on found money - using little or none of your own money. http://www.free-marine.com/linkoneminmillionaire.htm

Many years of working experience in Marine, Facilities, Construction has given the author material for writing e-books and articles related to engineering, and management. Subscribe to facworld ezine at mailto:facworld-subscribe@yahoogroups.com More information at http://www.free-marine.com and http://www.free-engineering.com







Google News - Top Stories

Washington Post

Alaska Inquiry Concludes Palin Abused Powers
New York Times - 1 hour ago
By SERGE F. KOVALESKI Gov. Sarah Palin abused the powers of her office by pressuring subordinates to try to get her former brother-in-law, a state trooper, fired, an investigation by the Alaska Legislature has concluded.
Video: Alaska Panel Finds Palin Abused Power AssociatedPress
Palin abused her power, legislative inquiry finds Los Angeles Times
CNN International - Washington Post - San Jose Mercury News - Houston Chronicle
all 3,646 news articles


New York Times

Panicky Sellers Darken Afternoon on Wall Street
New York Times - 33 minutes ago
By VIKAS BAJAJ Until 3 pm on Thursday, it seemed as if the stock market might escape another dark day. Richard Drew/Associated Press Thursday was the busiest day in the history of the New York Stock Exchange, starting quietly before a 90-minute free ...
Video: US Stocks Extend Huge Losses AssociatedPress
UPDATE 1-Wall St Week Ahead: For stocks, high anxiety rules Reuters
guardian.co.uk - The Associated Press - KHON2 - Computerworld
all 3,171 news articles


Calgary Herald

G-7 Commit to `All Necessary Steps' to Stem Global Meltdown
Bloomberg - 35 minutes ago
By Simon Kennedy Oct. 11 (Bloomberg) -- Group of Seven finance chiefs, meeting after stocks plunged and as a global recession looms, vowed to prevent the failure of vital banks while failing to unveil new initiatives for thawing credit markets.
Group of 7 Nations Seek Coordination in Rescue New York Times
A Global Strategy Washington Post
The Miami Herald - CNNMoney.com - The Associated Press - San Francisco Chronicle
all 1,001 news articles


Active Napa County brush fire consumes 150 acres
San Jose Mercury News - 1 hour ago
AP ST. HELENA, Calif.—State fire officials say a brush fire has consumed 150 acres and has led to the evacuations of homes east of St.
Active Napa County brush fire consumes 200 acres KSWT-TV
2 homes burned in Napa Co. wildfire ABC30.com
Examiner.com - Santa Rosa Press Democrat - KTVU.com - CBS 5
all 28 news articles


ABC News

Gay Marriage Is Ruled Legal in Connecticut
New York Times - 33 minutes ago
In Hartford, Crystal Pretzman of Willimantic, Conn., celebrated the State Supreme Court's decision to legalize same-sex marriage.
Gay marriage upheld in Connecticut by state high court San Jose Mercury News
Connecticut court overturns gay marriage ban Reuters
International Herald Tribune - The Associated Press - Boston Herald - BBC News
all 1,477 news articles

Google
 

Copyright © 2006 Computer Hunter - A Division of Arthur´s Job Base