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Aiming at the Ideal Garage

23rd September 1938
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Page 68, 23rd September 1938 — Aiming at the Ideal Garage
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A Foreman-mechanic Expresses His Views on the Type of Equipment Which the Good Garage Should Contain to Ease Repairs and Maintenance

MANY changes have taken place during the past 30 years in the treatment of commercial-vehicle repairs. and I think all practical mechanics will admit their indebtedness to modern repair equipment, in simplifying their work and rendering it far more agreeable than hitherto. Perhaps some of my readers have never used anything else but modern equipment, whilst others, still struggling along in poorly equipped workshops, wish their employers would spend a little more money to provide them with better tools. Be that as it may, a good deal can be learned by studying the advantages of modern repair equipment, from the perspective of the men who use it.

My own experience of repair work dates back to the time when we had to help manufacturers, by correcting inherent defects in early types. We had to make spare parts by

hand and, generally, agitate our brains to solve operating problems. Repair mechanics had to be real engineers in those days, able to operate all kinds of machine tool, and perform intricate fitting, sheet-metal work, forging and smithing; in fact, anything that came along when brokendown, vehicles needed to be put right.

Matters have changed now, partly because vehicle design is so much better, but principally by reason of the first-class tools and equipment, which simplify repair work in every way. Years of practical experience have given me decided views on the subject of workshop equipment, either for maintaining users' fleets in their own shops, or for dealing with trade repairs for vehicle owners generally.

Sound Planning Essential.

In the first place, the repair shop must be designed and built for the job. You cannot expect to do good work or to use modern equipment properly, if obliged to work in dark, cramped or•generally inconvenient workshops.

Next, we have to deal with the question of dirt and grease, the greatest of all repair bugbears. The workshop must be clean and orderly, whilst all dismantled parts must be cleaned quickly and effectively. Chemical degreasing plants appear to me as the best solution in this case, although I am not averse to modern paraffin-washers or caustic-soda tanks. I plump for chemical degreasing, because once a lorry has been dismantled, all the components can be put into a caged container and handed to a labourer who has, then, nothing more to do than immerse the whole lot in the tank and afterwards brush away residual rust, to leave all the parts clean and ready for inspection.

To savehand-labour for this work, and assist in other operations involving the movement of heavy parts, the workshop should be served by an overhead travelling crane, for which many uses are found in the chassis-repair shop.

It is essential, before proceeding far with repair work, to inspect all dismantled parts thoroughly. For this, a well equipped view-bench is necessary. Such instruments as micrometer gauges, verniers, depth gauges and other precision measuring tools are desirable, to enable one to give instructions to the mechanics about subsequent jobs, or to

issue clear orders about work to be done by outside firms. This applies more particularly to crankshaft grinding, where a universal crank-grinder is not installed on the premises. Engine-bearing work must be regarded as the most important phase of chassis overhauling and demands special attention. Few people, nowadays, indulge in the laborious practice of scraping bearings by hand, except, of course, when big-ends or " mains" require nothing more than a mere " nip-up." Many repair mechanics have, at some time or another, attempted to construct home-made boring bars, but few have succeeded in producing tools of the kind capable of affording the necessary precision to ensure long and reliable bearing life. I would, therefore, recommend the purchase of a really good instrument, capable of dealing with various sizes of crankcase. By that means, first-class results can be guaranteed, if we start with a crankshaft reground to predetermined journal dimensions.

The operation of reboring a set of crankshaft main bearings can then be entrusted to a good mechanic-improver, with the result that the crankshaft can be reassembled in the crankcase with no more work than " motoring " the bearings to ease off any initial stiffness. The same principle can be applied, to good effect, for dealing with connectingrod bearings and many good tools, for the purpose, are on the market. So far as re-metalling worn bearings is concerned, I am not sure whether one needs to bother about installing plant for the purpose, although, in some respects, a whitemetalling outfit is a useful addition to the equipment. As a rule, replacement bearings are so inexpensive that it generally pays to buy new sets from the manufacturers when a complete engine overhaul is in progress.

That is in accordance with my general views on repairshop equipment, for it is false economy to purchase tools for which regular use cannot be found, or those designed to recondition component parts which can be replaced, cheaper, by new ones purchased direct from the vehicle makers.

Cylinder-bore Grinding by Luck.

In the old days it was a frequent practice, for want of better facilities, to mount cylinder castings (usually formed in pairs at the time) on a large face-plate and attempt bore-correction with the aid of a grinding attachment mounted on the lathe saddle. One had to be clever, or rather, lucky, to make a good job of it that way.

To-day cylinder-bore boners have put quite a different complexion on the process and no workshop is now considered complete unless one be available. If things be arranged properly, the main reconditioning operations can be done simultaneously, in a well-equipped repair shop, thus reducing the time required to complete a thorough overhaul. Cylinder reconditioning plant is always a valuable acquisition for the repair shop and my firm, for example, have worked up a good connection, amongst local commercialvehicle users, by reboring worn cylinders and fitting new pistons at attractive prices. The apparatus is, thus, in almost constant use. Having completed the engine bearings and cylinder bores to a high standard of workmanship, it would be a great pity if the valves and their seatings were to he denied similar care. We must, accordingly, make use of a good set of valveseating and valve-facing tools. Hand-grinding of valves is far too slow a process to be worthy of consideration, especially when so many vehicles are equipped with six-cylindered engines, to say nothing of the eight-cylinderecl units.

The system of line assembly of repaired components calls for special attention to equipment designed to support the main chassis units while the work is in progress. Nothing is more conducive to bad workmanship than attempts to assemble engines. gearboxes and the like, without the aid of suitable stands. These useful adjuncts to the fitting department must be of sub stantial construction and adaptable to support units of

varying dimensions. Personally, I prefer -those which enable the engine to be turned upside down, for work on the bearings, and then righted for completion of the erecting processes,

Continuing my selection of useful repair equipment as now marketed, I must refer to the latest forms of brake-servicing appliances, having in mind those which facilitate removal of old facings and the riveting on of new ones. Mechanical truing of the facings while on the shoes is a great timesaver, and, as all commercial vehicles are, more or less, subject to heavy brake wear, the cost of installing this form of plant is soon justified. Furthermore, a smart lad will soon become adept at fitting new brake facings by the use of such a machine, thus leaving the skilled mechanics free to get on with work of a more difficult nature.

I am quite aware that heavy brake wear may also affect the drums themselves, but the item is not sufficiently important to warrant the employment of special drum-grinders, except in large workshops.

Since brake-testing plant has loomed to the foreground so much, of late, I cannot well avoid the subject altogether. I will admit quite freely that it is a fine thing to test a vehicle's brakes, on completing repairs but would hesitate to recommend installing this expensive plant in anything but a large repair department.

My own preference, for brake testing, is the simple combination offered by one maker, conc sisting of a band affixed to the tyre and a block engaging the head of an hydraulic jack. With the brakes applied, one operates the jack and reads the pressure at which the wheel begins to move. By that means one has a useful guide in making the final adjustments and can set the brakes to come into action exactly as required.

No repair shop can be considered complete unless a power press of about 50-tons capacity be installed. There is no end to the useful applications for this item on repair work, ranging from the removal of tight ballraces to the straight. ening of such parts as cardan shafts and steering links. Of modern bench tools, it may be said that their name is legion, so I will not attempt to enumerate them. The best way to tackle the business of equipping your workshop with modern bench and other tools, as distinct from equipment, is to walk around and notice how much time is being wasted when old-fashioned implements are in use! You will be surprised. Finally, I would urge the wider adoption of modern ideas on pit construction. Many general repair jobs need not entail the dismantling of chassis components, if suitable pit arrangements exist.

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