Harold Hall

First Page

Yet another version, having continuous adjustment for the height of the packing, and again one that I use frequently, is for the clamp bar itself to have a tapped hole and for a screw added to act as a built in jack, Photograph 6. This method is particularly good for low packing heights. Again, machine away the raised lettering on the head of the screw. To prevent the drill hitting the worktable note how in this example a clamp bar has also been placed under the workpiece to raise it from the machine table.

Using a stud to provide the adjustable packing is equally at home for mounting items onto an angle plate as Photograph 7 shows. In this case though, the packing stud can be firmly anchored in the slot of the angle plate before the height of the clamp bar is set. A major advantage of this method if multiple parts are being made is that the clamp will remain firmly in place between removing the finished part and fitting another. It will only be necessary to loosen clamping nut as flexibility in the set-up will be sufficient to permit parts to be removed and replaced with ease.

In this set-up it is worth taking notice of the fact that the clamping stud is also being used to hold in place a fence for setting the angle of the part being machined. The angle of the fence can be accurately set even before the angle plate is brought to the machine table making it an easier operation. I think that this example clearly illustrates the advantage of using an angle plate, rather than a vice, for such operations. If the task is other than a light one, a second clamp should also be fitted .

Additional Supports

Working with a single clamp should normally be taboo, certainly when the part being held does not provide for easy and secure clamping. In some cases though, access can be limited and getting more than one in place difficult. In this case, providing the part is not over complex and the machining operation not too arduous, additional support around the part will ensure a sufficiently secure mounting is achieved. Photograph 8 shows an example.

The Photograph shows the slot in a small clamp bar being made and illustrates another possibility, that is, sometimes holes in the component itself can be used for securing it. Actually, in this case, the two supports have added benefits in that further parts can be positioned so that the groove can be made without the need for measurement or reference to the leadscrew dials. All that is required is that the table stops, seen lower part of the Photograph, are suitably set, the process then is quick and easy. You see, there is no reason why you should not make a quantity of each size of clamp made.

Metalworking

Workshop Processes