The "Oneway" range of wood-turning lathes, currently in production by Oneway Manufacturing of 241 Monteith Avenue, Stratford, Ontario N5A 2P6, Canada, are of a most unusual design with all the major elements built up from steel fabrications and the bed constructed on a large-diameter, stress-relieved  steel tube. Welded to the tube is a line of supports carrying traditional, flat "ways" on which sit the usual headstock, tailstock and toolslide.
At the time of writing there are four models in the Oneway range, all made to order only and designated by the makers as the 1640, 2000, 1224- and 1236SD. A previous version, the 1018 "Mini" with a swing of 10 inches (a 5-inch centre height) and a capacity between centres of 18 inches, appears to be no longer offered. Other earlier versions included the 2436, 2416, 2036 and 2016 - where the first two digits of the number indicated the swing and the second two the distance between centres -  hence, for example, the Model 2436 had a swing of 24 inches and a capacity between centres of 36 inches. Both smaller and larger models have been (and may still be) available with bed extensions; the 18 inches capacity of the 1018 able to be increased to 42 inches while the larger lathes might be available with an additional 60 inches (or even more) of capacity - these versions being given with extra supports between the bed and ground.
The use of a single  tube for the bed of a lathe is interesting, and to appreciate its advantages consider first the open-section channel beds fitted to many cheap Chinese lathes; these are rather like a tin can with the lid removed, they can be easily twisted out of alignment and lack torsional stiffness. However, if the tin has its lid on, things are much improved and so, if a channel-section bed were to be changed for one made from welded square or rectangular stock, it would be very-much stiffer assembly. Unfortunately continuously seam-welded, closed-section material is very much more expensive than channel - and not something the manufacturer of an item built down to a price would want to use.. A tube however has advantages even over enclosed steel sections; it uses a minimum amount of material for a given beam strength (its mass increases almost in direct proportion to its diameter) whilst its torsional strength increases as the cube of the diameter - and its deflection (the amount of bend it suffers under load) decreases as the fourth power for any given twisting moment applied to it. Therefore, in practical terms, if the single 10.75" diameter bed tube of the Oneway Model 2036 lathe were to be compared with a lathe having two 5-inch diameter tubes of the same total mass, it would be four times as strong and, more importantly, would twist through only one-eight the angle for any given load. Playing with a sheet of A4 paper and rolling (and then testing) tubes of various diameters will quickly show how the mathematics of this equation translate into practical reality.
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The end of the bed tube (this is a Model 1018) is bracketed to both the bench and welded to the ends of the flat ways.
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Also built up from a tube, the headstock assembly of the "Large" lathe is welded to a stiff rectangular support and its spindle manufactured from a high-tensile steel hardened and finish ground all over. The nose is a M33 by 3.5 mm pitch thread which incorporates a locking arrangement to allow full-speed reverse with safety; the end flange of the Poly-V pulley is provided as standard with 6 holes for the locking plunger to engage with and an additional ring of 48 (optionally 96) holes for indexing work. The spindle runs in four bearings - a pair of sealed-for-life, deep-groove, pre-loaded ball bearing immediately behind the nose and a pair of "floating" ball races at the other end - and is driven directly from a high-quality, electronically speed-controlled motor (with a choice of 1.5, 2 and 3 hp) mounted directly beneath the headstock in the base of the stand. A 3-step, 10-groove poly-V pulley is provided to give three speed ranges: 0 to 800 rpm, 0 to 1800 rpm and 0 to 3000 rpm. To assist in changing the belt from pulley to pulley a section of the headstock is cut away at the top and provided with a heavy drop-in cover. Interestingly, the control box for the motor is mounted on a two-part arm pivoted from a bracket beneath the bed; it can thus be swung into any position, either in front of or behind the bed, which takes the operator's fancy.
Of fabricated construction, the tailstock of the "Large"  has a generously-proportioned 1.5" diameter quill (barrel) with a useful No. 3 Morse taper and 4 inches of travel. The assembly is fitted with an extra-long clamping handle and a robust bed clamp - whilst a welded-on "lifting" handle assists with its safe removal and replacement. 
Oneway lathes of the "Large" type really are just that - with tremendous physical presence, considerable weight and as much capacity as even the most experienced and enthusiastic amateur turner could possibly handle with safety; however, even though the lightest (the 1224) weighs 300 lbs and the heaviest (the 2436) 850 lbs, the overall lengths are not excessive; the shortest is just 40 inches long (as was the older 2016) and the longest only 60 inches. Prices are, however, are another matter, and the maxim of you-get-what-you-pay-for applies very strongly; these are not cheap machines built down to a price for the casual user but a quality product for the serious enthusiast and professional.
While the "Mini" lathe had exactly the same type of headstock construction as the "Large", it carried a smaller, 1 5/8" diameter No. 2 Morse taper headstock spindle with a 1" x 8 t.p.i thread; the entire spindle was hardened and ground and ran in exactly the same type of high-quality bearing arrangement as its larger brothers. In order to obtain a top speed of 4000 rpm the drive arrangement included both a continuously variable-speed, inverter-controlled 3-phase motor of 0.5 or 1 hp (the supply required being either 110 or 220 volts, 1-phase, respectively) and a countershaft (jack-shaft) unit with three Poly-V pulley carrying inch-wide, 6-groove belts mounted on the headstock-end bed plate immediately below the spindle. The three speed ranges covered: 0 to 1000, 0 to 2000 and 0 to 4000 rpm; however, because the drive system was biased towards a high top speed - this was, after all, a lathe for smaller work that requires high speeds for a good finish - the continuous slow-running speed was limited to not less than 150 r.p.m. Unlike the larger lathe, the tailstock of the 1018 "Mini" lathe was of traditional cast-iron construction with a smaller 1.125" diameter barrel but still with a still-adequate No. 2 Morse taper - and 3 inches of travel. The least satisfactory element in the lathe's design could be found in the tailstock spindle clamp - a crude, screw-down affair of the type which should only be employed on the cheapest of machines.
The bed and ways of the 1018 were identical in arrangement to those of the "Large" lathes, but based on a much smaller 4.5" diameter tube with a wall thickness of 0.25".
The Oneway web site is at: http://www.oneway.on.ca

Above and below: at the headstock-end of the 1018 the end support plate acts as a bracket to carry the 3-speed countershaft unit. As both motor and countershaft are fitted to pivoting brackets, both belts can be individually tensioned. A swing-open cover secured by a magnetic catch guards the mechanism.

A countershaft (jack-shaft) unit with three Poly-V pulleys carrying inch-wide, 6-groove belts is mounted on the headstock-end bed plate. The three speed ranges cover: 0 to 1000, 0 to 2000 and 0 to 4000 rpm.