Harold Hall

First Page

The Vee grove

The main method for using the device is for it to be mounted on the lathe's top slide with the drill in a drill chuck in the lathe's mandrel, more about that later. Because of this it is essential that the vee is exactly at centre height. If a conventional vee was attempted this would be difficult to machine and even more difficult to ensure it was at the correct height. Making a stepped vee with progressively smaller end mills and whilst mounted on the lathe's top slide, results in the accuracy required and also being an easy process. If like me you use metric end mills the increments will be in 2 mm steps, 16, 14, 12, etc. and at 1 mm depth increments. Not 2 mm increments as the photograph show that I did.

Photograph 4 shows that the top slide was rotated 90 degrees for this operation. The reason for this was that the traverse of the cross slide was just insufficient for the cutters to reach the right hand edge. As will be seen moving the top slide is not necessary when the finished item is put to use. If your lathe needs this extra reach but the top slide cannot be rotated a full 90 degrees all is not lost. All that is required is that the face being machined is at right angles to the lathe's axis. This can still be achieved even if the top slide is set at 45 degrees. As a last resort, temporary spacers could be placed between the cross slide table and the leadscrew mounting bracket to increase the traverse. If using the method shown in the photograph the actual machining is carried out traversing the cross slide only, the top slide only lets the jig start that much further back.

The final task on the body at this stage is to produce the groove that positions the bush holder assembly, Photograph 5. The set-up seen in the photograph uses a toolmaker's type vice though this is not essential. However, note how its mounting provides considerable freedom on its mounting position, very beneficial when working on the vertical slide with limited travel. It also enables a vice with a larger capacity to be used, also very worthwhile. I would therefore strongly advise the viewer who does at least some milling on the lathe to obtain such a vice. See my pages for modifying a economy drilling vice to produce a suitable toolmakers vice for the purpose, and doing this also on the lathe.

Bush holder assembly, Bar Clamp, Collar clamp.

These are made from rectangular stock and with the vertical slide and vice still set up from the above skim the ends of these to the quoted dimensions. Grip the part in the vice just projecting from the ends of the jaws and machine by traversing the vertical slide.

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