Ideal for the smaller workshop the Selig Sonnenthal branded open-sided shaper by Gebrüder Heinemann had a 19?quot; X 8?quot; table - and must have endeared itself to several generations of amateur engineers once its professional working days were over.
Fitted with dovetail instead of the more normal rectangular T-slots (the former appear to have been a short-lived, Victorian fashion) the 19?quot; X 8?quot; table had 15 inches of travel, was 36 inches from the floor, the height to the top of the tool-slide handle was 54 inches and the flywheel 15?inches in diameter - the latter doubling as the drive pulley and stamped 100 revs on some examples and 80 revs on others.
With its underside finished in a very harsh scraping pattern, presumably a method of holding pockets of oil, the table was equipped with a power-feed mechanism that incorporated several of the patented mechanisms - automatic feed-reversal, a soft take-up of the drive and an instant stop/start mechanism that left the drive system running but the table stopped.
Amazingly, the shaper was fitted for hand, belt and (almost certainly) treadle operation of the flywheel. The possibility of the latter system being used (though admittedly not fitted to any machine yet discovered) is evidenced by a pair of tapped holes in the base and corresponding fitting points that all align perfectly to hold that sort of mechanism. In operation, the flywheel turned a shaft connected to spur gears that in turn caused two parallel shafts to run in opposite directions. Each shaft carried a loose pinion (gear) that could be engaged by a dog-clutch controlled by a tumbler mechanism tripped by adjustable stops running in a T-slot along the front edge of the table. Both pinions engaged with a single, spring-loaded rack on the underside of the table (another part of the patent); while one pinion drove, the other idled - the shaft driving the cutting stroke being arranged to run more slowly than the one responsible for the return movement.
One serious problem with any reciprocating motion involving a heavy sliding table is the sudden impact imposed on the drive mechanism as it slams to a stop at the end of its travel (and was one of the reason for the adoption of hydraulic drive on grinding machines from the late 1930s onwards). To brake the table and then accelerate it in the other direction without undue mayhem - or concussion as the patent so aptly described it - the Selig employed a clever refinement. The mechanism involved a very powerful C-shaped flat spring - a "brake spring" - wrapped around and pinned to each of the dog clutches, their action being to cushion the drive until a positive stop was reached. One other effect of the mechanism was to allow an instant disengagement and re-engagement of the table motion - yet at the same time leave the drive system running so that an immediate restart was possible -so reducing the time when the tool was just cutting air - or "dead time" in the parlance of the day. A further refinement, used to smooth the drive take-up even further, was the method of attaching (or rather, not attaching) the rack to the table: the underside of the table was machined away to leave a hollow into which was attached, though its centre, a very powerful, long, flat, wave-form spring. The rack, instead of being bolted rigidly in place, was arranged to press up against the underside of the spring and had a pin through each end, the pins reaching up to catch on the ends of the spring and so allow the rack some slight cushioning movement as the drive was taken up. The Selig Sonnenthal table-drive arrangement makes an interesting comparison with that provided for the English Milnes planer.
*Mathias Hass was German, from St. Georgen in the Black Forest (Baden) but his patent appears to have been applied for world-wide and is recorded as being taken out in America, under No. 310996, during 1885. The German Patent office is also reported to have several patents registered under his name. Near to his home were the Weisser Company, who made lathes and milling machines, and Heinemann, a specialist in capstan types. In addition, during the 1930s in Schwenningen (only a few miles away from St. Georgen) an Adelbert Haas owned a factory producing universal grinding machines and simple lathes - perhaps there might have been some family some connection.
If you have a Selig machine tool of any kind, the writer would be very interested to hear from you.. Some pictures are high resolution and may be slow to load