CHAPTER 1
Introduction
The simple specifications for hand tools and equipment contained in this publication and the various notes relating to them were developed in connection with the Kenya Rural Access Roads Programme. This programme is a Government of Kenya (Ministry of Works) project supported by the World Bank, the British Government, USAID, and certain other Governments. Started in 1975, the plan was to build some 15,000 kilometres of simple unsealed roads in remote parts of the country using labour intensive methods during an approximate 10 year period. It is anticipated that over 10,000 people will be employed at the peak. Besides helping to reduce unemployment the programme has socio/economic merits in opening up remote areas, thus stimulating agricultural production and aiding education and medical care.
It will be appreciated that such a project calls for the use of very large quantities of hand tools such as shovels, jembes, etc., and simple equipment such as wheelbarrows. At the outset of the RARP the quality of these items was, in general, very poor leading to breakages, supply difficulties, and low productivity in the field. The basic reason for this very unsatisfactory situation was the practice of buying tools and equipment by tender at the lowest quoted price, resulting in the provision of tools of poor design which lacked strength and durability.
Regrettably this same policy of buying at lowest tender price is common in many developing countries, and results in similar unsatisfactory performances when the tools and equipment are put to work in the field.
Attached to the Kenya MOW in Nairobi was a Technology Unit which among other functions worked intensively on the upgrading of tool and equipment quality. By the end of 1978 this work had drawn to a successful conclusion and the simple specifications and other data in this book record the information developed, so that it is now available for labour intensive projects of many types in other countries.
It may be added that insofar as the Kenya RARP is concerned, work done on tool and equipment improvement and the use of these specifications when buying has been a major factor in eliminating shortages, reducing wear and breakages in the field, and increasing productivity. Thus the work has been cost effective and hand tools and equipment are no longer a delaying factor in the programme.
CHAPTER 2
Specifications
The full list of simple specifications 1 05-118 is given in the contents section at the beginning of the book.
It should be emphasised that these simple specifications are not intended to replace the more detailed national or international specifications such as BSS, SAE, etc, nor do they cut across the work performed by any Bureau of Standards. Rather, they represent practical and manageable information (together with simple drawings) which can be used commercially for buying, inspection, and testing, thus ensuring that the various items procured will be durable and give good productivity in service.
In order to obtain good quality durable hand tools the use of steel to reasonably controlled specifications is essential. The strength and behaviour of steel depends on its chemical composition (and heat treatment where relevant), and for this reason the required chemical composition of the steel forms part of each hand tool specification.
In the absence of a local steel industry much of the steel will have to be imported, a situation which applies particularly to the special alloy steel needed, for example, for axe manufacture (Specification 115).
At first sight the inclusion of chemical compositions in the specifications might appear to involve complications in the form of analysis for inspection purposes. Fortunately, however, there is a good correlation between the strength of steel and its hardness, and it is for this reason that hardness figures are included in each hand tool specification. The equipment needed for hardness checking (covering only 0.2% of items received – see section 6) is fairly simple and inexpensive and may be located in the store's facilities. Briefly, the checking process consists of pressing a diamond or hardened ball into the steel with a definite load. The diameter of the indentation gives the required correlation with the strength of the steel, based on standard tables.
Thus the need for chemical analysis can be reduced to occasional random checks, probably carried out at the local university, or similar institution.
It will be noted that each specification calls for the tool to be marked clearly with the specification number and the manufacturer's name and/or trademark. These points are important for keeping track of tools in the field and discouraging the introduction of low grade non-specified items.
CHAPTER 3
Tool Handles
Experience in several developing countries has indicated that a very large proportion of the problems encountered with hand tools in the field (on road, irrigation, and construction projects, for example) arise from the use of handles made from cheap unseasoned softwood, coupled with poor manufacturing quality. Breakages, loose tool heads, and unsatisfactory grips are typical problems, leading to poor productivity and waste of time.
This is surprising since suitable hardwoods are widely available, seasoning can be carried out naturally if kilns are not in use, and there appears generally to be adequate manufacturing capability either by machine, or, in rural areas, by manual methods.
Thus the manufacture of tool handles to specification is a vital and relatively easy step in the upgrading of hand tool quality and productivity in the field. The cost increase for a "specified" handle as compared with a "cheap" handle is modest, and no other single step can return such high dividends in terms of cost effectiveness and productivity as the manufacture of tool handles to specification from seasoned hardwood.
It is for this reason that specifications 113, 114A, 114B, 114C, 114E, covering handles for various types of tools are included in this publication.
Suitable hardwoods will have specific gravity 0.66-0.80 after seasoning and will preferably be long grained. Seasoning should be to a moisture content of 20% maximum, either by kiln or natural means. Natural seasoning may take about seven weeks. In view of the very large variety of hardwoods in different parts of the world it is recommended that the selection of appropriate types for tool handles be discussed and agreed with the Government Forestry Department (or similar official body) in each particular country.
In some countries manufacturing industries may have special profile turning lathes available on which tool handles can readily be manufactured. However, rural skills should not be overlooked and satisfactory handles can usually be produced by hand in rural areas. It is important that seasoned wood of the appropriate type be used – not just a branch cut off a convenient tree! To this end it may be desirable to supply the rural workers with standardised blocks of seasoned hardwood from some central (probably Government) source. For example for the jembe (hoe) handle, specification 114A, the standardised blocks would need to be 950mm x 62mm x 50mm.
A word of caution about axe handles, specification 114C. The attachment to the axe, specification 115, is vitally important and includes a wedge for assembly. The manufacture of axe handles and fitting them to the axe heads is preferably a job for experienced specialists.
CHAPTER 4
Wheelbarrows
It is difficult to visualise any labour intensive project which does not involve wheelbarrows to a considerable extent. In the course of the tool and equipment upgrading work for the Kenya RAR Programme it proved impossible to find a wheelbarrow in East Africa with satisfactory strength and life expectancy, apart from one or two very expensive imported items.
Accordingly the T U wheel barrow was designed and tested, using readily available hardwood for the handles and paying particular attention to the wheel/axle/tyre assembly – a major weakness in most designs.
The field tests proved satisfactory, the costs were economic (though higher than some local-poor quality wheelbarrows) and the item was put into quantity production with local commercial organisations.
All this formed the background of specification 107 (including drawings TF5 and TF7), which shows the design and construction of the TU wheelbarrow in sufficient detail to enable it to be manufactured in any part of the world.
The tyre was made extra wide to give a good "footprint", and of solid rubber for ease of production and elimination of field maintenance (inflation) problems.
The two nylon/molybdenum disulphide plain bearings will almost certainly be imported (as in Kenya), but as they amount to only 1% of the overall cost this can be considered a very advantageous trade-off for the much easier "wheeling" when fully laden, and the greatly increased (maintenance free) life which results from their inclusion in the design.
Wheelbarrows with crude wheel/axle arrangements are difficult to push due to excessive bearing friction, particularly with a full load. This usually results in the operator only partially filling the barrow with consequent loss of productivity.
CHAPTER 5
Trailers and Tractors
Many labour intensive projects, particularly in rural areas, involve the moving of earth, gravel, etc, in bulk over considerable distances.
Specification 110 covers a five tonne (hydraulic) tipping trailer developed in connection with the Kenya Rural Access Roads Programme. The specification is detailed and thorough yet the trailer involves no extraordinary skills as regards manufacture, although it is likely that the hydraulic rams and the tyres (with tubes) will have to be imported.
This development was an interesting and most constructive exercise with cooperation between the Kenya MOW, the Technology Unit attached to it, and certain commercial enterprises. The design proved very satisfactory on test and the trailer has been produced in quantity by three commercial firms. Field experience has shown that trailers built to specification 110 can be relied upon for good performance and durability under arduous operating conditions.
The appendix to specification 110 covers various matters which are important when trailers are being bought in quantity.
Since the use of the above trailers clearly involves tractors a few notes regarding the tractor/trailer combination may not be out of place.
a. Compatability
An important aspect of the combination involving attention to towing hitch, hydraulic reservoir capacity, load transfer (particularly on steep down grades), power to weight ratios, etc.
b. Tractor Power
Adequate power (including allowance for power drop-off if working at altitude) is a fairly obvious essential. Nevertheless it is also possible to overdo the tractor size with a consequent penalty by way of increased costs.
c. Tyres and Tubes
Tubeless tyres are completely unsatisfactory owing to air leakage following inevitable wheel rim distortion damage in service, hence the inclusion of tyres and tubes in specification 110.
d. Hitch
The hitch must be made from good quality heat treated steel, otherwise rapid wear will take place in service.
e. Hydraulic Hoses
Hose and pipe lengths and runs should be checked and any sharp bends or sharp radii should be corrected. Suitable clips and supports should be provided for hoses. Any sharp edges on which the hoses might chafe must be eliminated.
Leaking joints are an obvious but oft-neglected cause of hydraulic system problems.
f. Hydraulic Disconnect Coupling
This device automatically seals off the two sides of the hydraulic system when the tractor and trailer are separated. Per se the coupling is usually satisfactory but the danger of dirt getting into the hydraulic system is self-evident, particularly since the hose attached to the stationary trailer is often simply dropped on to the ground after being disconnected.
The drawing below indicates in schematic form a design to overcome this problem. It is, of course, essential that all components in the arrangement are robust, and also that operators are instructed to make use of the correct procedures!
CHAPTER 6
6. Procurement, Stores, and Inspection
Although this publication sets out to deal principally with specifications for simple hand tools and equipment a few comments on the above subjects will be relevant.
Indeed, the initial function of the simple specifications is to accompany all requests for supply quotations from manufacturers (or importers).
If quotations are requested, for example for "1000 Shovels", there is every chance that the articles bought will be at the cheapest price – and quite unsuitable for service in the field!
If, however, the quotation requests go out as "1000 Shovels to specification 105 attached" the manufacturer (or importer) will have to ensure that the shovels are made from good quality steel of correct thickness, that the dimensions are in line with the drawing, and that quality in general is sufficiently good to pass the inspection tests.
Shovels bought in this manner will be more expensive (maybe 30%) than the unspecified articles, but will have an operating life probably 500% longer besides considerably increasing productivity in service.
Thus the principle of "buying to specification" can be regarded as very cost effective.
As regards stores, the efficiency of any labour intensive project will be greatly increased by the provision of proper tool storage facilities and effective systems for the control of receiving (including inspection) and issuing to the field.
Before tools are put into stores it is, of course, essential that they be inspected to ensure that they are in line with the drawings and to specification generally. Thus the use of the simple specifications at "receiving inspection" becomes a second major aspect of their value. It will be noted that each specification has a drawing attached and includes a simple mechanical test procedure. In the case of hand tools a hardness checking figure is also indicated, to which reference was made earlier in Section 2.
It is felt that the following percentage checks at stores receiving will generally be adequate:
Hardness 0.2%
Strength 0.2%
Dimensional 0.4%
Thus taking a batch of 1000 shovels or jembes the quantities for checking, selected at random, would be two for strength, two for hardness, and four for dimensions. This checking will (or should be) virtually non-destructive.
CHAPTER 7
7. Maintenance in the Field
Although this subject is not directly related to the matter of specifications a few notes may be useful.
Assuming the specifications have been used for procurement and inspection into central stores there will be available for the particular project (road construction, irrigation, etc) a supply of good quality durable tools and simple equipment.
The field performance (life and productivity) will, as pointed out earlier, be greatly superior to that of unspecified "cheap" tools and equipment. This performance can be extended by the provision of elementary maintenance and repair facilities at field camps under the general control and supervision of the foreman. The basic equipment involved is simple and low priced, although the type will depend on the availability or otherwise of a supply of electricity.
Such "self-help" jobs as sharpening of jembes using honing stones, fitting of new handles to shovels etc, repairs to wheelbarrows, riveting of new panga handles, and similar elementary maintenance work should be well within the capacity of field camp personnel, and will be very worthwhile (cost effective) in extending the life and productivity of the good quality items which the project management has provided in the first place, i.e. has bought to specification.
A note of warning regarding welding. This is a job for operators who have had specialised training.
