email: tony@lathes.co.uk
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Polygon Hand-operated
Shaping Machine

The Large Polygon Shaper - Page 2

Made by Messrs Hunters Ltd. of 16-18 St. Bride Street, London, EC4 and looking rather like the swing-head "Bradley", the Polygon may have been in production circa 1900 to 1930. Thought to have been purchased by a previous owner in 1919, the first example shown below has unusually pleasing and clean lines with the crank assembly (normally just prosaic lengths of rod or flat bar), elegantly waisted and the operating arm having the maker's name cast in and its outer end formed into a curved hand grip.
Two versions have been discovered: a smaller model with a stroke of 6 inches and a robust 10-inch by 9-inch table with three T-slots, this offering just sufficient capacity for most model engineering jobs - and a very much larger version with an enormous stroke of 11.5 inches, a cross travel of 10.5 inches and a table 12 inches wide and 8.25 inches across. The latter version was claimed by the makers to be the largest hand-operated machine made in the UK - and must have required weight-lifting and endurance training to operate..
On both types, the tool slide could be pivoted on the end of the ram - and was held in place by a long through-bolt--power cross feed being provided by a snail cam and ratchet assembly, the amount of indexing being adjustable by varying the position of the pivoting arm carrying the striker pin.
George Adams, the London-based agent for Pittler lathes, also sold a version of the Polygon (his advert is shown at the bottom of this page) though he failed to mention its name in the descriptive text and instead called it his "No,2". Different from any other Polygon seen by the writer, the GA version was machined with a cylindrical base that fitted into a cast-iron socket bolted to the bench. The arrangement allowed the complete head unit to be swivelled - which may or may not have proved to be a useful function. It also appears that two forms of the table were available for the Adams version: one with standard T-slots of the type shown in the pictures below - but of a much larger section -  while the other had ones that resembled the shape of a pear. If the shaper in this form was made by the makers of Polygon machine tools, or modified by George Adams himself is not known. One version of the Polygon offered by GAwas more unusual still and, probably uniquely, combined the ram assembly with an ordinary bench vice; in 1903 it was listed at 10 : 10s : 0d and described as the, "
Shaper and fitter's vice combined"
Although today largely replaced by the small vertical milling machine, there is still a place in the enthusiast's workshop for a small shaper. As the writer never tires of pointing out, in the hands of a more knowledgeable and skilful enthusiast and, with sharp tools, it is quite astonishing what a variety of useful work these little machines can do.  One might imagine that using a hand-operated shaper, even a little one like the Polygon, 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 a 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 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.
Other Polygon shapers also though to have been offered and, if you have one, the writer would be interested to hear from you..
Other small hand-operated shapers available during the 20th century included the AdeptAlexanderArrowBensonBoyntonBradleyE.W.CowellDrummondFlexispeeedGeorge-Adams-Pittler, GravesLiverpool Castings & Tool SupplyOmerodPerfectoPolygonPortassRapid-LimeRobblak, and Tom Senior.





The very similar though more sophisticated swing head Bradley. With a conventional elevating knee on one side, the base was formed into a large socket at the back to accept the swivelling-head unit. At each side of the main cylindrical boss were elevating "V" pads, the function of which is unclear. The ram travel was 6" and the side movement of the head, which carried an automatic ratchet feed, a remarkable 10". One interesting point about the Bradley was the availability of a separate head for cutting internal keyways that interchanged with the standard clapper box.




Polygon Page 2 - The Large Polygon

Polygon Hand-operated
Shaping Machine

email: tony@lathes.co.uk
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