As mentioned earlier, if you have one of the smaller lathes then the 75mm long body
will present a problem if attempting to mount it onto the lathes faceplate as suggested.
If though the body is made in two parts, as shown in Sk. 3, then there should be
no problem. The machining method will be essentially the same and I will therefore
only detail where they differ.
The body should now be held in the four jaw chuck and bored for the cutter holder
(the operation shown in photograph 4). However, the presence of the four jaws will
make it very difficult to position the workpiece using the line scribed on the end
and a square off the chucks face. This can though be easily be overcome by making
the part at this stage out of 30mm square steel. The machining process will then
follow very closely the sequence already described with just one exception, being
the method of moving the body forward by 11mm for drilling the 6mm diameter hole.
The change to the method in this respect should be to loosen the appropriate jaw
and wind it back about 12mm. Now place an 11mm spacer, noting that the accuracy of
this is important, and close the jaw just opened onto this. Loosen the opposite jaw
and one of the side jaws, remove the spacer, move the workpiece forward by the 11mm
and re-tighten the two jaws just released. This will have moved the workpiece forward
by the required 11mm and the process then reverts to that already described.
Making the separate shank is straight forward and needs no explanation, do though
when making the thread in the top of the body make sure that this does not break
into the 6mm hole in which the feed screw rotates.
Having made the body from square material, machining the assembled parts as in Photograph
12 will be more time consuming, but otherwise not that much more difficult.
A Final thought
Having made the boring head you will no doubt feel a real satisfaction in having
made something apparently so complex but with relative ease. More important, you
will have acquired a piece of workshop equipment of a size that is difficult to obtain
commercially and that will open up scope for working on more complex projects on