email: tony@lathes.co.uk
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Robblak Shaper


Made by Roberts, Black & Co. Ltd., of 19/21 Brazennose Street, Manchester, England the Robblak shaper, was advertised until the mid 1950s. Its table was a useful 10" x 9", the tool slide could be adjusted through a range of 1.5", the cross-feed travel of the ram head  was  6" and the ram travel 7". It could machine material up to a maximum thickness of 3.5". It weighed some 70 lbs and was, therefore, substantially built in terms of a machine intended for amateur use. In design it was almost identical to the French "Rapide-Lime" (built between 1900 and 1926) and also the "Alexander" a very similar model, made in the UK and patented by the inventor, Mr. Alfred Hindley Alexander on 27th May, 1909 as No. 27,663. All versions suffered from the same intractable problem -  the table was an extension of the machine's bed plate. While most contemporary machines of the same class were arranged with their table formed as a simple angle bracket that could be slid up and down a machined surface on the front of the bed, that on the Robblak, Rapide-Lime and Alexander was fixed and, as a consequence, any coarse setting of work height was impossible. In addition, with limited room under the cutter, there was only just enough space to fit a small vice. Even so, on all machines, the table was of a generous size and provided with heavy-duty T-slots that would have allowed most jobs to be clamped in place.
It seems likely that the Robblak would have been fitted with a copy of the automatic, reversible table feed that had been patented on the Alexander. This mechanism consisted of a star wheel, mounted on and keyed to the hand-feed screw, that engaged with a pawl that turned it tooth by tooth. A stop was provided, in the form of a pin that could be inserted at either side of the pawl, and so reverse the feed direction.
One might imagine that using a hand-operated shaper is hard work, but this is not the case - though there are three basic points to get right: the first is tool sharpness, the closer to razor-sharp the better, with frequent attention to the top edge by an oil stone to maintain it; the second is to resist the temptation to move the handle too quickly while also taking time taken to establish the best rate for the job in hand. For example, fifty to sixty strokes a minute by hand on a 5 to 6-inch stroke machine might feel comfortable but, allowing for lost time at the end of each half stroke, this gives at tool speed of over 60 feet/minute - which is 30% greater than that recommended for high speed steel on cast iron. Experimenting with slower strokes will, surprisingly, often produce better results. Finally, the third consideration, which is actually two rolled into one, cutting depth and feed rate: it is possible, if you have the patience, to obtain an almost mirror finish with a very fine cut and the slowest possible feed. But it does take time…..


Auto feed mechanism: the knurled-headed stop pin could be inserted into one of two side-by-side holes in order to reverse the feed direction


email: tony@lathes.co.uk
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Robblak Shaper