Harold Hall
Rotary Table Using. Harold Hall
Workshop Processes
A rotary table is probably amongst the least likely items of workshop equipment to be found in the average home workshop, due in part to its relatively high cost but also its limited use. However, even though its uses are limited alternative methods of carrying out these tasks are often far from satisfactory as invariably they call for a lot of manual activity. Typically, when producing a curved slot, by drilling a series of holes and finishing the slot by filing.
One way of limiting the cost and at the same time providing an interesting project would have been at one time to make those seen in Photograph 1. However, unfortunately , “College Engineering Supply” who supplied the castings no longer list them. They are 150mm and 100mm tables and appear in many of the photographs that follow.
Photograph 2 shows a commercially available 150mm table and as can be seen is more robust than the CES table of the same size. Many commercial tables do though have the added advantage of being able to be fitted with dividing attachments, Photograph 3, though usually these are purchased separately. These will make some tasks easier to carry out whilst also increasing the accuracy of the finished result, placing holes on a PCD for example.
If you are also equipping your workshop with a comparable sized dividing head, not necessarily carrying the same supplier's name, it is possible that the dividing plate accessories will fit both the rotary table and the dividing head. A few minor modifications may be necessary but even so it is worth checking before purchasing two sets of plates, etc.
Also available with many commercial tables is a tailstock, seen in photograph 2. This shows that the height of the centre above its base is adjustable. Just why this is I am not sure but it certainly avoids the need for accuracy in matching its centre height to the rotary tables centre height at the manufacturing stage. Another advantage of this is that if you have a similar sized dividing head, one tailstock will provide for both items.
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All pictures can be clicked on to provide a larger view