Metalworking
Practical Action
Quality control
When working in a small workshop there are certain principles that will help in producing a
good product.
Plan the sequence of manufacturing
So that all the accurate surfaces are machined at one setting
The finished surfaces are not held in a vice or chuck
Take care over marking out and measuring
Parts that accurately made add quality to a product. Measuring at every stage of
manufacture ensures that errors are seen early on when they can be put right. Time
spent marking out is not a waste of time.
Remove all Burs
Burs are the rough edges created when metal is cut. These should be removed from
edges and holes
Don’t use emery cloth to hide inaccurate work
If the surface finish of a product is bad it means the tool is in bad condition, it is
blunt, the wrong shape or being used at the wrong speed.
Lean to weld properly and make strong welds
A good weld will be strong and will not need dressing. Dressing a poorly welded joint
can hide the weakness of the join and can cause problems later on.
Finishing
Finishing is very important and a good finish will help sell the product but it should
not be used to hide bad work. No amount of paint can make a bad product look good.
Product development and design
The products need to be attractive to potential customers.
This can be achieved by making items of high quality, that
are attractive, that are affordable and address customers
needs. Practical Action has developed a range of products,
for example Practical Action Southern Africa has developed
the following items.
Peanut Butter Machines
Peanut Roasters, Shellers
Manual and Automatic Freezit Machines
Bag Sealers, Beehives
Manual, Electric Oil Press Machines
Electric Gravity Maize Mills
Cyclone Maize Mills, Diesel or Electric
Dehullers, Diesel or Electric
21hp Diesel Engines
Electric Motors
Star Delta Starters
Double Cavity Brick Press
M C Roof Tile Machines
Brick Moulds, Block Moulds
Candle Moulds
Four Colour Screen Printers
Welding Machines 110, 140, 225amp
Figure 5: A large hand grinder
produced by Practical Action
Southern Africa. Photo credit:
Practical Action / Zul
Practical Action Southern Africa
P.O. Box 1744
Harare
Zimbabwe
Tel: (+263 4) 776107, 788157
Fax: 788157
Email: zimbabwe@practicalaction.org.zw
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