ROAD AND WORKSHOP by HANDYMAN
Page 36
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The Garage Lathe-3
APART from straightforward turning in the centre lathe, and using the tools previously described, the ability to bore accurately is of considerable value in the repair shop. This is not, however, just a simple task of pushing a parallelshank twist drill into a self-centre chuck and boring a hole, but one of using either the larger Morse taper drill and socket or, for really large bushes, housings, and so on, a boring-bar and cutter.
Time and money can be saved during
vehicle overhaul where the boring bar can be applied, and many items can be recovered by welding, brazing and boring that otherwise would need replacing or
sending to an outside repairer. Items such as detachable housings for gearbox, diff, or centre carrier can be built up and returned to original size in the hands of a keen operator.
The Simplest Type
The simplest form of boring-bar can work either open ended from the chuck, or between chuck and centre where the work will permit; it is a round, parallel bar. slotted through to take the doubleedge tool,. the tool being self centred on its own lips and locked in this position by a wedge. See Fig. I.
A variety of tools can be used to cover a range of sizes, and each will self centre on being placed in the slot and moved forward on to the lips. The bar should be as large as possible to ensure stiffness, and the largest tool used in a 1 in.diameter bar should not exceed 2 in,
Where larger apertures are to he bored, a larger bar should be used to avoid
vibration problems. With a range o tools suitable for the main " fit " sizes o bearing apertures and the like, this forn of boring out can provide 100 per cen accuracy. It is, of course, necessary tha the lathe saddle should be the borink type.
A very useful boring bar with a widt range of applications is the Nulok. Thi has a simple form of tool lock in thai the bar is drilled through its length and the tool locked by a centre bolt. Brown Bros. can supply.