MODERN METHODS OF RESTORING COMPONENTS.
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Some of the Interesting Processes Employed by Barimar, Ltd.
O(-AWING TO the loss of time and the cost involved in obtaining an entirely IA part to replace one which has broken in service, the practice of getting the component repaired has become increasingly popular with those responsible for the running and maintenance of fleets of vehicles. During recent years several concerns in this country have become prominent in connection with welding and other repair work, and of these the firm of , Barimar, Ltd., holds a prominent place. This concern has recently opened branch factories in Scotland, Ireland, and many parts of the world, and undertakes the repan of parts, such as broken or cracked cylinders, crankcases and crankshafts, damaged radiators, and, indeed, any other metal f omponent. of a motorcar chassis. The art of welding has been developed to such an extent that this process can be successfully applied to cast-iroe, steel, aluminium or bronze.
Two Methods are used, viz., oxy-acetylene welding a n d electrical arc welding. In the former case an intensely hot flame is produced by the mingling and burning of oxygen and acetylene in a blow-pipe, and this process has been found suitable for the repair of castiron or aluminium. For steel parts, such as crankshafts, the arc welding
process has proved superior. In this case, the part to be welded forms the negative pole of an electrical circuit, the welding rod constituting the positive• pole. An arc is struck between the two, the intense heat of which melts together the part to be welded and the welding rod applied for the purpose of adding metal.
We were recently able to watch these welding processes in operation at the London works of Barimar, Ltd., and were also shown the machining, inspection and testing of partsewhich had been repaired. The very thorough system employed ensures that when a part is returned to the owner it can be replaced in position with a minimum of trouble.
To enable components of all shapes and sizes to be emceesfully dealt with, a large number of up-to-date machine tools. has been installed, including lathe s, drilling machines, grinders, etc. There is, in addition, an hydraulic testing apparatus, which is used for applying pressure to the bores and jackets of repaired cylinder blocks.
The welding processes are extremely interesting to watch and deserve a Tittle further de scription. In the case of a crack, a strip of metal along the length of the fracture is first melted out by the application of the oxy-acetylene flame. The space-produced is then filled in with new metal, -which is melted off the welding rod and firmly welded to the part concerned. In order to avoid distortion troubles and to ensure a good joint, the part is brought to a red heat before welding, and is annealed after the operation has been completed.
When a piece has actually been broken away from, say, a cylinder block, the piece is trimmed on a grinding wheel, so that when replaced there is a marginal space between it and the surrounding metal. This space is then filled in with new metal, which welds the piece into position. By this method apparently hopeless wrecks can be built up, and, if some pieces are missing, similar ones are specially east and welded into place.
In the case of a' fractured crankshaft, broken, say, clean across a journal, the fractured ends are first reduced to a conical shape by grinding. A small portion of each is left untouched, so thatthe welder can put the pieces together intheir correct location. New metal is then built into the space between the two cones, and, finally, the journal is
ground to its original shape and size. Another interesting process consists in
filling up long and deep scores in cylinder bores, such as those produced by loose gudgeon pins. Needless to say, this filling process obviates the need for regrinding the cylinders, and so saves the cost of new pistons and rings. The damaged part of the bore is cleaned, and
is then surrounded by a copper bath filled with acid. The passage of an electrical current suffices to cause a deposition of the copper upon the cast-iron surface, and the deposit affords a firm and secure grip to the special alloy which is sulasequently melted into the seoies. Finally, trimming with a scraper or grinding wheel results in the return of the bore to its original shape.
Radiators are repaired by tinsmiths, who cut out the damaged tubes and replace them with new ones. In this way effective and permanent repairs can rapidly be made.
Needless to say, with Se many parts continually passing through the works, a very careful system of control has stion had to be instituted. When a ders. damaged component arrives, an
inspection is at once made and a report sent to the owner.
This report states whether the repair can be executed under the Barimar guarantee, which involves a return of the money paid if the repair is not satisfactory, or whether the repair must be
done at the customer's risk. Ninetyeight per cent, of the cases received come under the former category. Ab the same time,, the cost of the job is estimated, and a label is made out which follows the part into the works, and states the precise repairs required and the method by which they are to be carried out.
The employees who actually under take the welding operations are all highly skilled workmen, and have been with the firm for a considerable period. The speed and certainty with which they
carry out intricate repairs are well worth watching. Incidentally, the personnel for the branch factories was trained at the London. works. Special guards and tinted glasses are used by the welders, as the glare of the flame or arc is very damaging to the eyes.
In addition to repairing motor chassis components, work is carried out for the railways, electricity undertakings, shipbuilders, etc. While we were at the works an extensive repair was in progress on the turbine pump of one of the London County Council fireengines, and many other types of machinery have been repaired from time to .time. Motor vehicle components are, nevertheless, the speciality of the concern.