FOR MEASURING CYLINDER BORES.
If you've noticed an error in this article please click here to report it so we can fix it.
A New Tool Devised for the Fleet Engineer and the Repair Shop Foreman.
AA NEAT and accurate tool for measur_Ming the bores of cylinders is now being handled in this country by Mr. A. E. Menuge, Worplesdon, Surrey. It will be seen from the illustration that this consists of a rod provided with a convenient grip at the upper end of which • a sensitive dial indicator is Wed. At present this dial is calibrated in hundredths of a millimetre, but a, conversion table giving inch equivalents is provided with the instrument. At a later date dials will be available marked in thousandths of an inch.
A spindle running down the centre of the rod connects the dial at the top with a transverse plunger at the bottom. At the opposite side is a recess and knurled nut for the reception of rods of various lengths. The provision of a set-of these rods enables a large range of bores to be measured with the one tool.
The modus operandi is as follows:— The tool is first placed in a pair of callipers or a ring gauge, the size of which is equal to the nominal .bore of the cylinder to be measured. The face of the dial is then turned until the
pointer gives a zero reading. If the instrument be then placed in the cylinder variations in the bore will be indicated by movements of the needle to one side or other of the zero mark, according to whether the diameter is larger or smaller than the correct size.
B34 If it, is merely desired to check the bore for parallelism or oval wear, it 'is, of course, unnecessary to set the instramerit by means of callipers. It can simply be placed in the bore, and moved up and down to show the variations.
A useful feature is the provision of a tee-piece at, the lower end, slidably mounted and pressed outwards by a light spring against the cylinder bore. This has the effect of steadying the instru ment when in use. Some people prefer an instrument in which there are three prongs in place of two,. but we are informed that an ample steadying effect is obtained by means of the sprung teepiece. For motorcar work two sizes are available, with setting rods covering a range of 60 mm. to 1e0 mm., and 100 mm. to 160 mm. respectively These are retailed at £6 10s. each. Other sizes are available, front 20 mm. up to a maximum of 400 mm.
The instrument is handy to use, easy to read, and extremely well made. There is no back-lash in the mechanism, and we should imagine that it will be capable of withstanding prolonged usage vithout wear. "