Tools to Speed Engine Reconditioning
Page 35
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First-published Details of the New Cuthbert Motorized Connecting-rod Borer and of a Motor-driven Rough-boring and Oil-grooving Machine,
AGREAT part in developing machine tools of a reasonably simple but highly effective nature for
. the reconditioning of engines is being played by Warner Engineering Equipment, Ltd., By-Pass Road, Guildford. This company is the sole concessionnaire for the Cuthbert range, which is manufactured by it, and references to several machines of various types, such as the main-bearing line-hour, have already appeared in our pages.
A recent addition to the number is the Cuthbert motordriven connecting-rod borer, which is believed to be the only power-operated specialized equipment of this type manufactured in this country.. The essential details of this new tool can easily be seen frofn the accompanying illustration.
Engineers who have to deal with the class of work for which it is intended will realise that the principal requirements of a boring machine for soft metals are rigidity and ability to perform the work at high speeds. Additionally,. there must be some really sound method of holding rods ef different dimensions and covering a fairly wide range. Accuracy is, of course, a sine qua non.
The bed, which is short, is sturdy, and the end of the boring bar is spigoted into a white-metal bearing in the short part of the bar extension carried by the tailstock. It engages with a No. 4 Morse taper in the headstock mans drel, which itself runs in a pair of white-metal-lined tubular bearings. The drive from the reversible motor is through a +-in. V belt, and three speeds, of approximately WO, 950 and 1,400 r,p.m., are provided. Four suitably spaced holes in the boring bar accommodate the toff's, which perform the operations of rough boring, finish boring, and both right-hand and left-hand facing and radiusing. The tools can quickly be set to fine limits by means of a special micrometer. A diamond cutter can be supplied for finish boring when desired.
The capacity is for rods up to 18-in. centres and about 64-in, overall width of big-ends. Bores up to 4 ins, can easily' be tackled.
a It is obvious that mach study has been given to the design of the holding jig for the rods. The requirements here were speed, accuracy of set-up, and rigidity of grip without distortion, and these appear to have been met in an able manner,
When setting-up a rod, the bolts of the little-end clamping jig must be loOse. The rod, without its cap, is then placed upon the appropriate littleend mandrel and lightly clamped. A setting-up half cone is then placed in contact with the bar, and the rod drawn up until the flat face of this half cone is in contact with the half bearing. Thus the.rod is adjusted for centre height, moving the little-end jig to its correct position for a whole set of similar rods. For up and down position, the rod is set by moving the half cone along the bar and adjusting the rod until the sloping sides of the half cone simultaneously engage the two big-end bolts.
If any doubt be felt regarding the machining accuracy of these bolts, a check is provided by observing where the joint between steel and white metal intersects the edge of the half cone in relation to engraved lines on the lastnamed, which constitute an important feature of this device. The lines enable the setter-up to ascertain at once whether the rod is on centre or not.
The two shoulder-clamp vice-jaws are then, adjusted to a suitable position an the rod and securely clamped. 'These jaws have universal mountings; they cannot, therefore, wring the rod. The cap may then be mounted and securely bolted-up without any danger of straining the rod or of moving it. Finally, a cap-clamp bridge with appropriate distance pieces in position (a range of these is supplied with the machine) is then slid on to the big-end bolts, and the cap-clamp brought into position by means of a handwheel, when the distance pieces automatically take up their correct positions and may be locked. They constitute, together with the cap-clamp, an outboard steady and a guide for further rods of a set; consequently, there is no need to use the setting-up device after the first rod has been dealt with.
When removing all rods, or when setting up after the first rod of a set, there is no need to remove the caps, as the complete rod may be passed between the, boring bar and the tailstock after the bar extension has been slid back in the tailstock.
The approximate price of this machine is 1.50, Further to this, the company is making an additional tool, which is known as the Cuthbert motorized roughboring and oil-grooving machine. It is securely mounted on a cast-iron bedplate, and will rough-bore main bearings, covering the same range as the line-boring machine to which we have already referred. It will also take care of all oil-grooving which may be required.
The need for such a tool has been indicated after investigations in the trade, where it has been found that the pafticular jobs which will be tackled by this machine are often a bugbear, " The maker of these and other types of machine-tool equipment has gained an excellent reputation and an increasing sale by reason of the sheer practical and efficient nature of the products from this factory. Originally, some of the tools of the types concerned were imported, often with great difficulty and at high cost, and for a time the company had difficulty. in obtaining the necessary material, but the demand, in some cases from Ministries, has forced the issue, much to the advantage of those concerned with the repair and maintenance of motor vehicles, who find that their Work can be speeded up,, whilst being performed more accurately.