For DRIVERS, MECHANICS & FOREMEN.
Page 21
If you've noticed an error in this article please click here to report it so we can fix it.
A PRIZE OF TEN SHILLINGS is awarded each week to the sender of the best letter which we publish on this page ; all others are paid for at the rate of a penny a. line, with an allowance for photographs. All notes are edited before being published. Mention your employer's name, in confidence, as evidence of good faith, Address, D., M. and F., "The Commercial Motor," 7-15, Rosebery Avenue, Landon, E.G. 1.
Lamps Alight— Light your lamps at 4.49 in London, 6.15 in Edinburgh, 4.43 in -Newcastle, 4.64 in Liverpool, 4.55 in Birmingham, 5.0 in Bristol, and 5.34 in Dublin.
An Improved Ball-race Housing.
The sender of the following communication has been awarded the Ws. prize this week.
[1797] " H.M." (West Bromwich) writes :—" For some time the ball-race housings on the transmission shaft of an electric motorbus chassis aused a lot of trouble. As shown in the sketch herewith [We have had it re-drawn.—En.] each ball bearing is carried in a, shell. The shell is screwed into the end of a caststeel bracket and adjustment of the position of the ball bearings along the shaft is effected by screwing this housing a little further in or out of the bracket, as the case may be. The inner end of the housing is castellated, and it may be locked in any desired position by means of a pin, which is caused to enter one of the slots of the castellated pistons. "Trouble develops very quickly at the threaded portion and the threads wear down n a very short time. After i r a few replacements had been made, and as it appeared that each new housing lasted a little less time than its predecessor, I set out to discover, if possible, the cause for this apparently abnormal wear, and, later, to devise some means of circumventing it.
"After a little consideration, it became clear to me that the defect was inherent to the design of the part, and that our troubles were clue to the fact that there was no direct support under the actual ball-race, and that the load, therefore, had a leverage about the threaded support of about in. Owing to the fact that adjustment had to be allowed for, it was not possible to screw the housing tight against a shoulder, consequently the' whole of the load fell upon the thread. Havingjound the source of the trouble, the remedy soon sgested itself, and I altered the arrangement as follows :— " I bored the bracket for the housing to a depth which would cover the innermost possible position of the ball-race, and extending just beyond the inner face of the ball bearing. The diameter of the hole I made as large as possible without touching the threads of the screwed portion. The outside of the housing I trued up in the lathe, and on to it I shrunk a steel collar. The collar was then turned up in its place on
the housing, and made a good fit in the newly-bored hole in the bracket..
"The ball bearing now has a saiisfactory support, which is in the direct line of the load, and this support does not in any way interfere with the adjustment of the housing, nor with its accessibility."
Repairing, not Renewing, Gudgeon-pin Bushes.
, [1798] " J.K.O." (Scotstoun) writes :—" Recently, in the course of the general overhaul of a commercialvehicle engine, it was discovered that the small-end bushes of the connecting rod were rather badly worn. This defect was only discovered at a late stage of the overhaul, when the delay which the preparation of new bushes would have entailed could net possibly be entertained. It therefore became necessary to devise some means of taking up the wear in the existing ones. This was accomplished in the following .manner.
"The two bushes affected were removed from their respective rods, and a lonqitudinal saw-cut was made in each. A piece of steel foil, three thousandths of an inch thick, was then wrapped once round each bush, and the latter was then replaced. The effect of the foil was, of course, to close up the saw-cut, and thus to reduce the bore of the bushes. They were scraped to fit the gudgeon pins, and the job was completed."
A Temporary Road Wheel Repair.
[1799] " A.E.S." (Northampton) writes I suf fered a nasty skid recently on some slippery roads near Warwick. The front wheels of the Albion which I was driving commenced to go first, then the rear swept round, and before I knew where I was the near side rear wheel hit the curb and was badly smashed. "Being, in a manner of speaking, three miles from anywhere, I thought my job was settled for the weekend, as a wheel with most of the spokes splintered does not easily lend itself to a wayside repair. How
ever, I found a village wheelwright within a short walk, and got him to assist me.
• " We first of all removed the wheel, and then straightened it on a plate. Some bar-iron, 14 in. by I in., was cut into convenient lengths and drilled so that one end of each could be secured by one of the hub bolts, and the other end bolted to the felloe of the wheel, With three of these plates on each side of the wheel I was able to get home."