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Sorby Woodturning Lathe - England

Sorby Continued Here

Literature is available for Sorby lathes

Produced until 2003, the Sorby lathe was manufactured in-house at the Company's main works in Athol Road on the west side of Sheffield, South Yorkshire - just across the road from what used to be the well-known Portass lathes works. Apart from industrial-sized examples, by the 1980s the Sorby was one of very few English woodturning lathes left on the market that was not only properly designed but also carefully engineered from top-quality materials and assembled by skilled men.
Based on two hard-chromed solid steel bars, the 6.5-inch centre-height lathe had a very heavy headstock constructed (as were all the other cast parts) from a strong spheroidal-graphite iron; three bed lengths were available offering 24, 36 and 48 inches between centres.
Running in sealed-for-life ball races, the No. 2 Morse-taper headstock spindle could be supplied with either a 1-inch x 8 t.p.i English or 33 x 3.5 mm metric thread. Drive was by a 5-step Poly-Vee belt from a headstock-mounted hinged motor plate that carried either a 1 h.p. single speed motor (with a no-volt safety starter) or a DC variable-speed unit with electronic control; with the former the spindle speeds were a useful 265, 550, 950, 1500 and 2400 rpm - and with the latter a more impressive 0 to 3000 rpm. Although the DC motor-equipped version would run through the entire speed range without the need to change belt position, the lathe retained the complete 5-step pulley arrangement of the standard model; this had a considerable advantage, for, by positioning the drive belt on the pulleys normally used for the slowest speed, the torque was greatly enhanced and the top speed physically limited to a maximum of 360 rpm - thus making the turning of very-large diameters a much easier and safer proposition.
Able to be rotated through 360 degrees, the headstock assembly was secured to its base by a positive "cam-lock" mechanism which (unlike those on cheap imported contemporary lathes) clamped it to the baseplate with absolute security; turning the headstock through 90 degrees - and passing the bed rails through its base - allowed the optional large-diameter bowl-turning rest to be mounted. If the headstock was rotated through 180 degrees to face in the opposite direction to normal - and the lathe fitted with variable speed drive and some type of independent, remotely-mounted tool rest - the possibility of turning very large diameters indeed became a real possibility.
Equipped with a hollow, No. 2 Morse taper barrel that allowed it to be adapted as a steady to assist with long-hole boring, the tailstock was clamped to the bed rails by the same type of quick-setting handle as used on the lathe's other fixtures - the design allowed the operating angle to be instantly changed by simply by lifting the lever from its splines and letting it spring down into a new position.
A wide range of accessories was available including a special roller-bearing tipped fixed steady to assist with long, slender work and a very interesting eccentric chuck which could be not only be used in ordinary faceplate and screwchuck modes but also in combination with a hexagonal ball-and-socket driver that allowed the workpiece to be angled at up to 20 degrees away from the spindle axis. The versatility of the device was explained in a 12-page instruction manual..

The Sorby could be supplied on a unique and heavily-built box-section stand with the tailstock-end of the bed supported on a sliding clamp. This arrangement allowed the bed bars to pass through the headstock and accommodate the large-diameter bowl-turning attachment - see the picture immediately below.
Unlike many outfits of a similar capacity, both the stand and lathe could be quickly dismantled  into their component parts for ease of moving or storage.

Not an illustration of the first job that an amateur should attempt, but an example of how the bed bars could be slid through the headstock - with the latter turned through 90 degrees - and the maximum bowl-turning capacity of the machine, 30 inches in diameter, fully exploited.

This is one of the few maker's pictures which gives a true impression of the mass and weight of the machine.

The drive was by a 5-step Poly-Vee belt from a headstock-mounted hinged motor plate that carries either a 1 hp single-speed motor (with a no-volt safety starter) or a DC variable-speed unit with electronic control (shown here); with the former the spindle speeds were a useful 265, 550, 950, 1500 and 2400 rpm - and with the latter a more impressive 0 to 3000 rpm. Although the DC motor-equipped version would run through its entire speed range without the need to change belt position, the lathe retained the complete 5-step pulley arrangement of the standard model; this had considerable advantages, for, by positioning the drive belt on the pulleys normally used for the slowest speed, the torque was greatly enhanced and the top speed is physically limited to a maximum of 360 rpm - making the turning of very-large diameters a much easier and safer proposition.

The 5-speed Poly-V belt headstock drive managed to combine an excellent speed range (265 to 2400 rpm or 0 to 3000 rpm with the variable-speed DC motor option) with a vibration-free, high-grip drive.
On the variable-speed version (which retained the headstock pulleys of the standard version) if the drive belt was positioned on the pulleys normally used for the slowest speed, the torque was greatly enhanced and the top speed physically limited to a maximum of 360 rpm - making the turning of very-large diameters a much easier and safer proposition.

The No. 2 Morse-taper headstock spindle ran in sealed-for-life ball races and could be supplied with either a 1-inch x 8 t.p.i English or 33 x 3.5 mm metric thread.

Rear view of the headstock showing the hinged motor plate and variable-speed DC motor. The large handle level with the motor plate released a cam and allowed the headstock to be swivelled on its mounting plate.

Unusual double-toolrest saddle. The unit was freed and locked with one twist of the handle - and could be slid and pivoted freely on its mounting.
Made in a very strong spheroidal-graphite, the unit was offered as a separate item to replace the weaker units found on some Record woodturning lathes.

The tailstock had a hollow, No. 2 Morse taper barrel allowing it to be adapted as a steady to assist with long-hole boring.

Substantial tailstock-to-bed clamp.

Close up of the roller bearings fitted to the ends of the fingers on the fixed steady.

Once a very common fitting on woodturning  lathes - even less expensive ones - the indexing attachment has been a neglected accessory for many years. Its inclusion as standard equipment on the Sorby offered the chance to carry out all sorts of imaginative work on wood held between centres or on a faceplate.

Fixed steady with roller ends on its fingers - an essential precaution on a version intended for woodturning which helped to minimise marking and burning of the workpiece.

Sorby Continued Here

Literature is available for Sorby lathes

Sorby Woodturning Lathe - England
email: tony@lathes.co.uk
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