Listed by the factory for many years as having been first manufactured 1935 the 9-inch "Workshop" South Bend was actually in production during late 1933 as the "Model 5", with the earliest promotional literature yet discovered being a January 1934 pamphlet of ready-prepared advertisements for dealers to place in their local press. In April of 1934 the company produced a simple guide to the new lathe as a 3-fold sheet, printed on both sides and showing a heavily re-touched picture of a lathe rather different to the ones advertised in January. The April lathe had a round knob on the apron to engage the clasp nuts and a top slide quite different to any seen on a South Bend before; its lower casting was bolted down through semi-circular slots at each side and had a  "turned-up" end that acted as a support bracket for the feed screw. In the illustration the bed and feet appear to have been cast as one piece (though this is almost certainly artistic licence), while the tailstock was shown as a casting without daylight beneath the spindle line. There is a good chance that this machine was a prototype, pressed into service as a photographic model and with preparatory work done on the catalogue (which may have been for internal use only), during late 1933. If you have a South Bend like this (shown below), please do make contact, it's a very rare machine indeed. By mid 1934 the lathe was sufficiently well-established to appear in a Repair Parts Bulletin, dated 15th August, and the official sales brochures were in circulation. Although the first catalog must have been numbered No. 5-A (though an example has yet to be found) the following editions 5-B, 5-C, 5-D and 5-E (the latter in two versions with one having most prices removed), were dated on the front cover as October 1934. Strangely, although all were dated identically, the printer's chronology on the rear varied: 5-B was printed on 3-20-35, 5-C on 10-27-34, 5-D on 10-29-34 and both editions of 5-E on 10-27-34.
At around the time that the Model 5 Type 405 was launched, South Bend were also working on a new small lathe, the Series 20 Toolmaker. When introduced in early 1934, under Catalog No. 520, this new machine was priced at $158, twice the cost of an ordinary and basic 405 at around $75. Although a special machine this new lathe was, in fact, little more than a copy of the regular 8-inch Model, produced from 1931 until 1933, but increased in size by around 20%. In addition to an identical design the two lathes also shared their changewheels, these being of 18 although, oddly, the stud gear on the output of the tumble reverse had a 1/2" bore instead of the 9/16", the Company providing a set of three with each lathe of 16t, 32t and 64t (the ordinary changewheels, of course, not fitting..). Screwcutting chart here
Like the Model 5 the Series 20 had no option of a power cross feed, nor a screwcutting gearbox, carriage travel for both threading and feed being by engaging and wearing out the leadscrew half-nuts.
One special aspect of the ordinary 8-inch was a rather magnificent built on countershaft (seen here) and this too was made available for the Series 20, though in a modified form as the vertical casting, being fastened to a larger lathe, required some additional clearance for the rear of the headstock and backgears. Although the Toolmaker's was shown in the 1934 Year Catalogue, by the middle of 1935 it had disappeared, perhaps setting a record for the shortest production run of any South Bend model. However, although the original 405 used a different bed to the Series 20, in 1936, when the 405 morphed into the 415 (and later 9-inch Workshop Model), the Series 20 bed was adopted for this much improved version. Full details of the Series 20 can be seen here.
In order to distinguish the various versions of the Model 5, the lathe was given a Model Type designation that reflected its drive system:
Model 5 - bench lathes for drive by line shafting
Model 405 - equipped with a bench countershaft or on floor legs with an adapted bench countershaft drive
Model 205 - mounted on cast-iron legs with drive from a wall or ceiling-mounted double friction countershaft
Model 205 - on cast-iron legs with an oil pan tray and a double-friction countershaft
Before the well-known 3-model range of the late 1930s (A, B and C) the lathe developed through the Type 15, a machine with numerous detail improvements - although of almost identical general appearance.
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9-inch "Workshop" Model 405 driven by the bench-type countershaft. The same Model number was used when the lathe was bench mounted.

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Although, at a cursory glance, the original Model 5 and "9-inch" of the mid to late 1930s appeared very similar, there were many differences and the former can be immediately identified by a distinctive oil hole, formed as a lip just above the leadscrew clasp-nut handle - or, if the very early catalogue is to be believed, by a round knob to engage the clasp nuts. However, the Model 5 also varied in other significant ways and, as the evidence shows, the design cut too many corners to keep the price low and South Bend were obliged to make several modifications during the first six months of production. In addition, as the new lathe was brought to market, there were a number of other very minor changes with the screw-on, spindle end-thrust ring secured by a grub-screw on early models but a split-clamp on the later (as it was on the later 9-inch Workshop model); the location of gib-strip screws in the cross slide was also modified and doubtless other small differences exist that will only be found by a careful comparison of several examples. The changewheels on the 405 were, at 20 DP, of a finer pitch than the "Workshop" type and the compound gears (two gears on one shaft) were fitted with distinctive pinned sleeves and (presumably to make sure that an owner who took them apart could not possibly be confused) the larger of the pair carried cast-in letters proclaiming, "compound gear" and a note of the ratio obtained. The leadscrew, at the point where the gear fitted to its end, had a diameter of 5/8", later increased to 9/16". The leadscrew used on all Model 5 and Type 405 lathes was an Acme form, 3/4-inch in diameter 8 t.p.i. left-hand pitch - and bought in (as it seems were all South Bend leadscrews, from a specialised supplier of such items).
Instead of the later more versatile and adaptable twin-arm forked changewheel bracket (the banjo), the one used on the Model 5 was a simple, single-slot device, with some evidence that even this was beefed up after the initial batch of lathes had been produced. In place of a proper "tumble-reverse" mechanism (by which convenient-means the leadscrew could be isolated from the changewheels, or made to revolve so as to cut either right or left-hand threads), a 5/8"-diameter by 21/2"-long "reversing stud" allowed a 32-tooth flanged changewheel to be incorporated into the gear train to generate left-hand pitches - but at a cost of some inconvenience to the operator. The stud was retained by a hardened and "blued" square-headed bolt (of the same size as those used to lock both saddle and top slide) threaded into the casting near the backgear handle and bearing directly against a dimple in the shaft. Even though relatively fine-pitch changewheels of 20 D.P. were used, the smallest gear in the original standard set was only a 24t and the largest a 69t; this specification, combined with the limitations imposed by the single-slot changewheel bracket, made it difficult to set up a compound-reduction gear train to give a slow enough carriage feed. Reference to the range of changewheels supplied with early and late 9-inch lathes shows the improvement brought about by including both smaller and larger gears and the introduction of a forked bracket to carry them: gears supplied with the very first Model 405 were: 24t, 30t, 33t, 36t, 39t, 42t, 45t, 48t, 54t, 60t, 69t that limited the treading range from 4 to 40 t.p.i. Almost immediately an alteration was made and a compound gear pair with 110/20t added to the set that, combined with the other gears, gave a finest feed of 0.0028" per revolution of the spindle (120 t.p.i.), so enough to give a good surface finish. To help beginners identify the fine-feed gears the pair on the banjo arm were clearly marked: compound gear 1 to 5 (with 110/20t) and, on the leadscrew, a single gear marked  turning gear 105t. The later, more fully-developed "proper" 9-inch models (with a forked banjo and the gear DP changed from 20 to 18) were equipped with: 16t, 24t, 36t, 40t, 44t, 46t, 48t, 52t, 54t, 56t, 60t, 80t,  a 72/18t compound and an 80t idler with a boss that gave the same span of 4 to 120 t.p.i. Interestingly, reference to pictures in the October 1934 catalog shows that South Bend must have reacted quickly to improve the situation for, though a single-slot bracket is shown in Bulletin 5-D, a 72/18t compound and the distinctive boss-equipped 80t idler gear (as supplied with later lathes) are also illustrated; these were, presumably, included as an interim measure to slow the feed rate until the improved bracket could be put into production to give a threading range that extended to 60 t.p.i. A screwcutting chart for a single-slot banjo machine that includes these "between-model"  gears has yet to be found - but, knowing the detailed attention South Bend paid to such matters, would almost certainly have been produced. The changewheel chart for the 405 was, naturally, unique to the model and in its original form riveted to the front face of the changewheel cover. Before production of the 405 ceased (and almost certainly coinciding with the change to a double-slot bracket) it had been replaced by a larger and more useful version, complete with diagrams, and moved to the larger surface on the end face of the changewheel cover.
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Above: Hidden away in the factory archives until 2007, this illustration of an early South Bend Model 5 Type 405 (bench-countershaft) 9-inch Workshop lathe is a heavily retouched picture dated April 1934. This may have been a prototype lathe, built in late 1933 and pressed into service as a photographic model before production examples were ready. Note the entirely different top slide - bolted down at each side through semi-circular slots and with the end of its base casing curved upwards to form a bracket for the feed screw to pass through. The apron and leadscrew clasp-nut knob are unique, as is the apparent casting of bed and feet as one. Also obvious is the lack of polishing on the carriage and tailstock handwheels.

By the middle of 1934 the Model 5 lathe (this is a type 405) was beginning to take on the appearance of the later models - though this example has significantly different bed feet

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Also unique to the Model 5, the changewheel guard was smaller and its mounting pin was not, as on later machines, of eccentric form to allow a neat adjustment of the fore-and-aft fit but instead set into the guard with what appears to have been a lead-like substance - an unfortunate method of assembly that allowed the material to creep and the guard to drop under its own weight and eventually foul the end of the spindle. The front of the guard was fitted with a small, elegantly shaped knob for the owner to grip - though as the cover had no form of lock, and could just be swung open, its inclusion seems to have been purely cosmetic.
Thought at a glance identical to later headstocks the early version had minor differences with a unique-to-the model backgear (not interchangeable with the later type) and a 3/4"-bore spindle that, on its introduction carried a nose 13/8" in diameter with a 10 t.p.i thread (later 11/2" diameter 8 t.p.i U.S.F thread). The internal taper of the spindle nose was (unlike later machines) a standard No. 3 Morse taper but the sleeve-down adaptor  (to reduce the nose to a No. 2 Morse) was smaller than that on later lathes with the larger spindle nose. Owners also report examples of early lathes with (8 t.p.i) spindle-thread diameters of 11/4", though these dimensions have yet to be confirmed as a catalog specification. It is possible to exchange the entire headstock on a 405 for a later type or even, if everything is in good condition, just the spindle assembly - and so have the benefit of being able to use the far more commonly-encountered nose fittings. The initial drive from the recommended 1/4 h.p., 1700 r.p.m motor was by V-belt to a narrow flat pulley on the countershaft. From there the drive passed via an inch-wide flat belt to give 6 direct-drive spindle speeds of 202, 353 and 630 rpm and 39, 68, 122 r.p.m in the 5 : 1 ratio backgear. Fitted with the optional 2-step pulleys the number of speeds increased to a more useful 12 with the top speed being 1163 r.p.m. Besides the pair of adjustable and non-adjustable bench countershafts the lathe could also be equipped with a double-friction reversing system intended for use in a shop equipped with line shafting . Speeds with alternative countershafts would, of course, have varied somewhat from the maker's official figures. One option mentioned in the April 1934 brochure - and thought not to have been repeated - was drive by a 1/2 h.p. gasoline motor.
Running directly in the cast iron of the headstock, the spindle was not (by reference to its omission in the catalog) hardened; however, it was lapped into its bearings to ensure that it would have a long and trouble-free life. Even though the "Workshop" was intended to be a relatively inexpensive lathe South Bend, unlike many other makers,  took care to protect the spindle bearings from the ingress of dirt and grit through the headstock bearing oilers and, instead of a simple straight drilling directly to the spindle (though which the operator could squirt both oil and dirt) the 9-inch had wick-feed felt pads let into machined slots directly beneath the spring-cap lubricators. While the front bearing felt pad was square in section the other was round and its ends bore against a metal spacer on one side and the retaining nut on the other, so providing lubrication to them as well.
While the 405 carriage looked, at a glance, identical to the later versions it was, in every detail, different: only a single square-headed pusher bolt was used to lock the top slide to the cross slide and, under heavy cuts, was unable to hold it in position; this was the most serious weakness of the early design but quickly corrected by fitting a matching bolt on the left-hand side. The saddle was of noticeable lighter construction with the wings on the tailstock side being shorter to the extent that the left and (larger) right hand radii almost blended into one (instead of a short straight section between them) but the cross slide (in order to help get the tool up to centre height) was rather thicker; unfortunately, although the main section of the slide that bore on the ways was the same length (with 5 gib-strip adjuster screws) the "duck's bill" cover at the rear was too short and exposed the feed screw to the wearing effects of swarf and dirt. Although not obvious from the illustrations, the micrometer dials were also smaller and, interestingly, the cross-feed nut unique to the model being in cast-iron and a little longer than the later type - but with its mounting boss smaller in diameter. The square-headed bolt used to lock the carriage to the bed was fitted to the right-hand rear wing - it later being moved to the right-front. The distinctive lip surrounding the oil hole on the face of the apron (it was used direct a supply of oil into a channel formed into the top surface of the upper leadscrew clasp nut) must have been abandoned because of its tendency to catch dirt and swarf.
Although the No. 2 Morse taper tailstock had a very distinctive open section in the centre of its upper casting, it otherwise appears to have been identical - apart perhaps from a nominal 1/8" less spindle travel - to that used on all later models. Photographs of an original 405 can be seen here.
By 1939 the South Bend 9-inch Workshop range had evolved into three models: The "A" with screwcutting gearbox and power cross feed; the "B" with power cross feed and screwcutting by changewheels and the basic "C" with hand cross feed and changewheel screwcutting. Before the introduction of this new range the original Model 5 underwent a number of changes to become, evolving, from around September 1935, through a model known as the Model 15. Early examples of this version retained some Model 5 features including the rear part of the headstock, where the backgear bushings are formed, the tailstock handwheel and the saddle, apron and apron controls. However, the initial version of the 415 was the first in the Series to have a proper tumble-reverse mechanism (to reverse the rotation of the leadscrew) together with a conventional right-hand pitch leadscrew. All these subtle (and inconsistent) variations are probably accounted for by the factory using up already-manufactured parts..

A production Model 5 Type 405. This retouched picture from a sales catalo disguises the sweeping curves of the tailstock-end saddle wings. Note the visible changes in comparison with the earliest-known picture: a different bed and mounting feet; a heavier changewheel bracket; a slightly altered changewheel guard; an entirely different top slide and modified apron and leadscrew clasp nut handle.

Mid-1934 9-inch "Workshop" South Bend lathe in its original Model 5 form (Type 405 with bench countershaft).
The NRA Code sticker showed the lathe was built under contentious trade regulations imposed by the National Recovery Administration (i.e. recovery from the recession of 1929/30). The act was eventually neutralised by a chicken slaughter company on their appeal to the Supreme Court in 1937.

The inexpensive but non-adjustable "Simplex" countershaft, driven by the inner flat of a V belt from a V pulley on the motor, was a unit already offered for use with the "Junior" and "Toolmaker" lathes. While this lathe has the changewheel chart riveted to the front face of the changewheel guard, lathes produced a little later had an enlarged version, complete with diagrams, on the end face. It is doubtful if the words "South Bend Workshop Lathe" were cast into the end cover but, if your 504 is like that, the writer would be interested to hear from you.

By 1933 South Bend already had a wide range of countershafts types available but in late in that year introduced a new design with an over-centre, adjustable-tension arrangement and an integral motor platform. A double pulley could also be fitted to the motor and countershaft giving a total of 12 speeds with a high of 1163 rpm. The unit was also offered for the other small lathes in the range: the "Junior" and "Toolmaker". Note the "trade-mark" South Bend use of a V-belt pulley on the motor and a narrow, flat pulley on the countershaft.

Spot the differences: smaller micrometer dials; a single square-headed on the right-hand rear wing; a single square-headed bolt to lock the top slide swivel; a noticeably thinner saddle; the thicker cross slide with its very short "duck's bill" cover at the rear and a shorter top slide.

Although looking exactly like the later headstocks, the early version had minor differences that prevented the backgears being interchangeable and a spindle that, on its introduction carried a nose 13/8" in diameter with a 10 t.p.i. thread (later  11/2" diameter 8 t.p.i U.S.F thread). The Morse taper was originally a No. 3 but the larger spindle nose of 1934 allowed this to be increased to near the size (but not exactly the same as) a No. 4; in both cases a reducing sleeve was normally used to bring the final fitting down to a No. 2 for regular work. Owners also report examples of lathes with (8 t.p.i) spindle-thread diameters of 11/4", though this figure has yet to be confirmed as a catalog specification.

Model 5 Single-slot changewheel bracket and the special stud to mount an extra gear in the train to cut left-hand threads. The compound gear appears to be a 72/18 as supplied with the later lathes.

The changewheels set up to give a fine feed compound reduction. From the length of slot visible above the top gear it would appear that this was not the finest feed that could be arranged.