email: tony@lathes.co.uk
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South Bend Lathes Models 5, 205, 405 & Type 15  - Page 2   
Original Versions of the "Workshop" 9-inch Lathe

Models 5, 205, 405 & Type 15 Home Page   

Model 15    Original, well-preserved Model 405

South Bend Home Page    South Bend 9-inch Workshop Home Page   

Although no manual was printed for the Model 5 or 15,
an interesting catalog is available and other South Bend Literature


This beautifully kept 405 has been maintained by its owner John Crombe for over 30 years. Its ID tags carry the following inscriptions: 405-Y, 9" x 3' serial number o56447, Type- Work.B. Hor.Plain,MDr., Overall Length of Spindle 11-13/16". It was shipped from the factory on December 15th, 1934. A few minor modifications have been made to enhance the machine's usability including bed wipers on the saddle and tailstock, thumb-screw locks on the compound slide rest feed dials and a very neatly arranged a bull-wheel indexing attachment.

Standard compound reduction changewheels in place

By December 1934 the distinctive lipped oil hole for the leadscrew clasp nuts was no longer used.

View showing the long, single-slot "banjo" used to carry the changewheels. At the 8 o'clock position, relative to the end of the spindle, can be seen the hole used to mount a simple 5/8"-diameter by 21/2"-long "reversing stud" that allowed a 32-tooth flanged changewheel to be incorporated into the gear train to allow the generation of left-hand threads. The stud was retained by a "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.

Fine-feed compounded gear train in place.

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. With these and others gears in place the finest feed was set at 0.0028" per revolution of the spindle.
Note: the original South Bend drive system did indeed have a V-belt pulley on the motor driving a narrow flat pulley on the "non-adjustable" type of countershaft.

Above and below: the very short cross slide of the Model 5 (that left the rear end of the feed screw exposed), the single topslide retaining screw (it should be a square-headed bolt not a hexagon socket screw) - and the shorter, tailstock-end curved-edged saddle wings - all are clearly evident in theses views.

Model 5 Type 405 top-slide feed-screw handle and micrometer dial

Model 5 Type 405 cross-slide feed-screw handle and micrometer dial

Early chart as displayed on the front face of the changewheel cover
Enlarged version here

Above: later Model 5 screwcutting chart as mounted on the end face of the changewheel cover


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 carriage feed that was slow enough for very fine feeds. 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.
As all pre-WW2 South Bend screwcutting and other plates are smooth on the rear, it's likely that they were produced by a process called chemical milling (rolling through a die or stamping leaves an imprint on the back). While it's possible that during the 1950s a cheaper silk-screen process was used, before then enamel was used to colour them. A paint in power form was applied in the low areas and then heated to melting point; the paint ran to its own level producing a superb, durable finish. A final touch was to lightly polish the raised letters and numbers. South Bend would not have produced their own plates, this was a process best left to a specialist maker.


Models 5, 205, 405 & Type 15 Home Page   

Model 15    Original, well-preserved Model 405

South Bend Home Page    South Bend 9-inch Workshop Home Page   

Although no manual was printed for the Model 5 or 15,
an interesting catalog is available and other South Bend Literature


South Bend Lathes Models 5, 205, 405
& Type 15  - Page 2   
Original Versions of the "Workshop" 9-inch Lathe
email: tony@lathes.co.uk
Home   Machine Tool Archive   Machine-tools Sale & Wanted
Machine Tool Manuals   Catalogues   Belts   Books  Accessories