email: tony@lathes.co.uk
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Holbrook Lathes - Model B No. 9
continued in detail on Page 2

Manuals are available for Holbrook lathes

Holbrook Home Page   Holbrook Model B & C No. 8   

Holbrook Model B No. 9   Holbrook Model T Lathes

Model 5P Precision Plain Lathe  Holbrook Minor 1960s - 1980s

An Apprenticeship at Holbrook   Holbrook Edgar Lathe   Serial Numbers

Holbrook Model C No.10   Holbrook Type B13, B17 & B21

With a centre height just one inch greater than the lovely little No. 8 model, the superbly constructed 4.5" x 28" Holbrook Model B No. 9 lathe managed to weight, at 952 lbs., over twice as much  - with the bed being especially massive and having a deep support in the centre as large as the feet at each end. Built from the early 1920s until deleted from the catalogues in the mid 1930s, the Model B No. 9 appears to have been Edgar Holbrook's homage to  the American Cataract QC toolroom lathe - the lathes having beds of almost identical design and an exact copy of the top slide. The top slide was also fitted the same threading quick-withdrawal arrangement - all other Holbrook lathes, and most other lathes of British design, having this mechanism on the cross slide.
Several examples of the Cataract have been found in the UK (all carry dates suggesting that they came over during WW1) and Holbrook would have had ample opportunity to examine one and learn from it. As far as is known just three examples of the Holbrook survive and production numbers must have been low. The owner of both a Cataract and a Holbrook Model B No. 9 comments that, while the various casting on the Cataract are all beautifully proportion yet remarkably "light", those on the Holbrook are very much heavier but still beautifully cast and machined. The difference might be accounted for by the noticeably superior American method of dealing with cast iron where a combination of pattern-making and foundry skills allowed much thinner sections to be employed yet of entirely adequate thickness for their particular function.
Fitted with a sleeve down to a No. 2 Morse taper, the 1.25" bore headstock spindle of the Holbrook ran in phosphor-bronze bearings that were parallel internally, but tapered externally and fitted with screwed rings to pull them into their tapered seats in the headstock casting. 12 spindle speeds (including those from the 4 to 1 ratio backgear) were provided and ranged from a low of 18 to a high of 858 rpm.
Though more substantial than that those fitted to the No. 8 lathe, the screwcutting gearbox and apron were both arranged and controlled in exactly the same way. The tailstock had a larger diameter, graduated barrel and, of course, a 2 Morse taper. Exactly the same range of standard equipment was supplied with this lathe as with the No. 8, and the general information given for that unit also applies this lathe.
Although all Holbrook lathes were especially well made with fine detailing, the Model B No. 9 stands out as being rather special with almost all surfaces and components fully machined and not just the essential mating surfaces. One owner describes the cosmetic finish as being akin to that found on the engine block of a Bugatti where enormous trouble was taken to make its appearance as impressive as possible.
A notable feature of the lathe was the very heavy and complex countershaft, this being carried on two massive cast-iron uprights bolted to the back of the headstock-end plinth. Inside the countershaft was what may have been the first type of Matrix multi-plate clutch, this reliable and effective unit being like those commonly found on motorcycles with the driven plates connected to a central splined shaft and the friction plates carrying tabs on their periphery that engaged with the driven drum.

Pictures of a Holbrook Model B No. 2 undergoing a thorough rebuild can be seen here

Holbrook Model B No. 9 arranged for independent countershaft drive

For comparison: the not-dissimilar circa 1917 Hardinge Cataract "Quick-Change-Swing Precision Lathe"

Holbrook Model B No. 9 on the maker's "self-contained countershaft stand". with a massive overhead drive system
The 1 HP motor was contained within the left-hand cabinet leg on an adjustable rise and fall plate and drove upwards by flat belt to a ball-bearing countershaft unit fitted with a multi-plate clutch. The clutch-operating handle was positioned just above the chuck, convenient for left-hand operation. The countershaft unit over the middle part of the lathe was an optional extra, and designed to drive high-speed grinding, milling and drilling spindles at up to 16000 rpm.

End view of the complex and heavy overhead drive system fitted to the Holbrook Model B No. 9 lathe.

Relieving equipment and speed-reducing "sub-head" installed on a Model B No. 9 lathe

A dividing head was available that screwed onto the spindle nose. It is shown here
being used in conjunction with a slide-mounted high-speed milling and grinding head.

Lever-action collet closer - the Cataract draw-bar is a perfect and the spindle takes 5C collets

Now very rare, this Holbrook Model B No. 9 was found on a farm not far
from the navel base of Portsmouth where it had begun its active life

A view from the back shows the massive nature of the overhead drive support casting

Much work to do - but an early clean down has started

- Holbrook Model B No.9 Continued on Page 2 -

Manuals are available for Holbrook lathes

Holbrook Home Page   Holbrook Model B & C No. 8   

Holbrook Model B No. 9   Holbrook Model T Lathes

Model 5P Precision Plain Lathe  Holbrook Minor 1960s - 1980s

An Apprenticeship at Holbrook   Holbrook Edgar Lathe   Serial Numbers

Holbrook Model C No.10   Holbrook Type B13, B17 & B21

Holbrook Lathes - Model B No. 9
email: tony@lathes.co.uk
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