Holbrook CB8

[CHRISTOPHER MILLS 1Participant @christophermills1]

To add to my 1940s CovMac, a large lathe, I have this week fortuitously acquired a little one, from the same era – a Holbrook Model B No.8 Toolroom lathe.

A little beauty, with taper turning, it is presently lacking its pulley cone gear and counter-shaft. I would ideally like to connect with another owner, (or somebody with knowledge of this model), so that I can work out what it needs to complete these areas. I am just to be guessing at present. There is some remainder of counter-shaft arrangements on the back of the headstock. At present it only has, effectively, a single gear, running off the motor, its top speed of 1320 rpm. For its age, I would say it is in pretty remarkable condition. Very little needs doing to it, apart from cleaning, one or two lever knobs replacing, and pulley cone and counter-shaft replacement.

I will post more detailed shots as I go. This model of lathe seems to be highly regarded by Holbrook enthusiasts, and I am looking forward to ownership. It will help me complete a number of items contingent to restoring the big CovMac.

Holbrook, a firm based in Stratford, east London, later moved out to Harlow, Essex, and they were eventually subsumed, I believe, into the Alfred Herbert Group.

Of about Myford proportions, overall, 4 inch swing, and about 20 inches on the bed, I think she weighs about 500lb. It came with a 4 jaw and a 3 jaw chuck, taper turning unit, and a bit of cutting equipment, a few dead centres, drill chuck, etc.

Am bringing her home on Tuesday this coming week.

I would also like to track down visuals, or examples, of centre and travelling steadies, which I believe came originally supplied with this Holbrook model.

Most striking visual feature of this lathe is a milled front face to the whole bed. I have never seen that before. It is quite striking. It does not show up too well in this photograph. It has 27 screw-cutting options off its nine cog gearbox. How we attain three off each gear is not quite clear to me, yet.

 

 

Edited By CHRISTOPHER MILLS 1 on 04/04/2015 14:01:52

[CHRISTOPHER MILLS 1Participant @christophermills1]

Toolroom lathe from the 1940s

[Neil WyattModerator @neilwyatt]

Very nice, another great find!… but please that key out of the chuck

[CHRISTOPHER MILLS 1Participant @christophermills1]

Not me, Neil, it was the vendor. But he had at least taken it out before I arrived on the scene.

Oops, though, I am now remembering your publication protocol – and if you want to remove that picture, Neil, I am happy to get a better one without the chuck key.

[Neil WyattModerator @neilwyatt]

No worries Chris, I think it will act as a salutary reminder. Let he who hath not got a dent in his lathe cast the first stone…

Neil

[CHRISTOPHER MILLS 1Participant @christophermills1]

Just to remind, pertinent of my careless lapse in publishing a picture of a dangerous set-up, kindly pointed out to me by the alacrity of our Editor –

NEVER LEAVE A CHUCK KEY IN A CHUCK

No excuses, no lapses. No nasty accidents.

NEVER LEAVE A CHUCK KEY IN A CHUCK!

Please.

Edited By CHRISTOPHER MILLS 1 on 04/04/2015 20:23:29

Edited By CHRISTOPHER MILLS 1 on 04/04/2015 20:25:40

[Brian WoodParticipant @brianwood45127]

Good advice Chris and Neil, the story went round the Rolls Royce apprentice training school years ago about the young man wearing his chuck key——.

It was further backed up in the workshops, in those days when long hair was all the rage, with a very graphic safety poster of a scalping from a drilling machine, it really was quite shocking in its impact. Still makes me feel sick to think of it.

Happy Easter!

Brian

[Neil WyattModerator @neilwyatt]

My nephew works on ambulances. Suffice to say that injuries like 'degloving' are still not uncommon.

Neil

[Cornish JackParticipant @cornishjack]

Christopher – 4" swing or Centre Height??? 4" swing would be Unimat -ish.

Rgds

Bill

[Ady1Participant @ady1]

Holbrook Model B No.8 Toolroom lathe

[CHRISTOPHER MILLS 1Participant @christophermills1]

Many thanks gentlemen – Sorry, Cornish Jack, it is of 4 inch centre height.

Lathes.co.uk certainly like this model, thanks Ady1 – "Famous for their high quality toolroom lathes, the English Holbrook Company concentrated mainly on popular and hence profitable medium and larger-sized back-geared and screw-cutting models – although they also made a superb, almost-Rivett-like precision bench lathe, the Model B No. 8."

It sounds like praise indeed. I am yet to see any imagery which shows me fully how the cone pulley and motor were organised together, behind the headstock.

It will be a bit clearer when I have the lathe in my possession. Moving it is not the feat of logistics which was needed to move the CovMac – the little Holbrook will go into my car.

[CHRISTOPHER MILLS 1Participant @christophermills1]

This lift looks alarming, but this was the only way to balance and pick up a Holbrook Model B No. 8. Heavier than I thought, it was a struggle for three of us to get it in the Passat – we got it out with two, under less hurried conditions. I reckon it is between 500 & 600 lbs of metal.

It is now safely stowed, and we damaged nothing, and nobody got hurt. The engine crane, as with the CovMac – a delightful lifter – but, with its steel wheels, a really terrible mover on anything but marble smooth surfaces. I might convert this baby to take rubber, mini car-type wheels. Any suggestions would be welcome. With rubber wheels, I am sure this would be so much more versatile a machine to use.

 

 

Edited By CHRISTOPHER MILLS 1 on 09/04/2015 09:33:19

[robjon44Participant @robjon44]

hi all, in the metalwork room at my secondary school during his introduction to the art, the teacher pointed out a repair in the middle of the wall mounted blackboard made by the chuck key of an elderly Boxford embedding itself having travelled a good sixty feet to get there, I confess to being impressed. Fast forward a few years to my apprenticeship and there were several Holbrook lathes on the centre lathe section and at least one in the toolroom, all held in high regard by skilled turners who used them, I myself was entrusted with one for a while. Finally in those politically incorrect days I left a chuck key in for 10 seconds and my chargehand removed it, stepped into the gangway shouted "fore" and propelled it a considerable distance along the floor, a very red faced apprentice then had to retrieve it whilst subjected to a round of applause and some barracking, lets just say that nearly 50 years later I aint forgot !

[Manny lambertParticipant @mannylambert86533]

Hi I am new to this forum, I do believe that your lathe is a C8 holbrook same era as model B. The difference is this had variable speeds up to 5000 rpm. I just sold a model B complete with all original equipment. This model C has the geared headstock. They both swung 8 inches. This model you have just acquired is very rare. Good luck with it.

[CHRISTOPHER MILLS 1Participant @christophermills1]

Thanks, gents.

Manny, I agree – it appears to be a C8.

It is also badged on the headstock plate " D.664 " Nobody seems to use that designation, today.

Apparently, Holbrook enthusiasts term this one today as the " CB8 "

I will be converting it back to a form of variable drive, and any suggestions would be welcomed.

There are choices, from a 3 phase motor with an inverter, or, apparently expensive, a DC servo set-up?

I have been told not to skimp on HP, for reasons of torque

[CHRISTOPHER MILLS 1Participant @christophermills1]

This Holbrook lathe originally ran a 2 HP variable, step-less speed motor made by Ward-Leonard, with a top speed of 5,000 rpm. The strength of machine castings, shown here in an underside view of the headstock, proves how it was designed to take such input.

Apparently, at top speed of 5,000 rpm, according to lathes.co.uk, you could balance a coin, end on, upon the headstock. Probably best an old threepenny bit.

The variable motor is long lost – two previous owners were running it as a single speed machine – it presently has twin pulleys coming off a single phase 1 HP Brook Compton motor.

[Clive FosterParticipant @clivefoster55965]

Christopher

Nice find.

If you've not already seen it E-Bay item 20132724456 "Holbrook Model B No 8 4" centre height" has some pictures of the factory countershaft arrangements for the ordinary all belt driven version without electronic speed control which may prove inspirational. Listing is up until 16th April but may close early as the machine is under offer so best grab pictures quickly. Click to enlarge first.

Hefty engineering.

Clive

 

[Manny lambertParticipant @mannylambert86533]

Hi again, I now have a smart and brown 1024 with a 3 phase, 3 speed motor, 415 volts.The lathe now has retained its 12 speeds and they are variable and reversable. I would use a 1.5 hp 220 volt 3 phase motor, a 2 or 3 speed motor would be excellent choice and yes it can run directly off an inverter drive. I removed the electrical panel with the relays on my machine and only kept the santon 3 way switch(stored the rest away if needed at future stage) But beware you cannot change motor speeds electrically without first switching power off to inverter but it was the simplest solution. My motor has 10 input wire from the santon switch and the santon switch is fed directly from the inverter. I personally would not exceed 1.5 hp, its plenty of power for this model. To increase torque try and find a 2 speed gearbox if they are available. Or set up pulleys but of course it means moving belts. A 3 speed motor will work fine and with the inverter give you more scope than any other solution. To recap my motor has low, medium, high speeds , the motor speed desired is set before switching inverter on. Hope this helps Manny

[CHRISTOPHER MILLS 1Participant @christophermills1]

Thanks gents – I am beginning to ponder electrics in re-converting to variable speed drive.

Manufacture date – Holbrook enthusiasts have identified from their records, and the machine's serial number, 8401, the year this lathe was made – 1950/51.

I was thinking the finish might have been a bit too good for wartime production.

[CHRISTOPHER MILLS 1Participant @christophermills1]

Here is a better view of my Holbrook CB8, showing all its controls, some of which I have no idea of function in. One lever, central to the apron, has taken a bad bash, and is bent to the left. One refinement is a micrometer wheel which fine tunes movements in the carriage. You can see it bottom right of the apron front, a small wheel, beneath the lock nuts lever.

[toptiggerParticipant @toptigger]

Hi, Is the apron on this Holbrook CB8 easily removed in order to make the lathe lighter for lifting ?

[BazParticipant @baz89810]

Simon, the apron is fairly easy to remove, not much harder than taking off a Myford apron. Trouble is that it won’t make that much difference to the weight. I owned a B8 Holbrook until fairly recently and during the 40 years of ownership it was moved four times and from bitter experience the best way I found to lift it was with a ladder and rope. The lathe was lashed underneath the ladder and with two people it could be lifted quite easily. The cast iron base was another matter, the top was basically a four foot by two foot surface plate and was seriously heavy.

[Stig LeedhamParticipant @stigleedham56071]

Like to see others have the same lathe as I do. Wonder if someone can help me. I have no manual and would like to make the metric change gears for my C8 electric. Does anyone out there know what dimensions the metric change gears are?

Also the apron on my lathe has tight operations so won't engage cross feed full. I will attempt strip clean and rebuild. With the help of a manual the task would be smoother I feel.

[Brian WoodParticipant @brianwood45127]

Hello Stig,

The gear dimensions are:-

Bore 0.500 inch with 0.125 inch keyway. Wheel width is 0.500 inches. All the gears are 20 DP of 14.5 degree pressure angle. I imagine genuine Holbrook gears will be hard to find so it might be helpful for you to know that Myford change wheels will fit. They are also 20 DP, and of the correct pressure angle and of course readily available. They are a bit narrower at 0.375 inches and the bores will need to be sleeved down from 0.625 inches and have a new keyway cut

I have a factory copy of the metric tooth chart for those lathes but you might like to know there is another full set of gear charts in my book 'Gearing of lathes for Screwcutting' which also gives tables for Metric, BA, DP, Module and a number of more obscure pitches.

ArcEuro stock the book which was written and published before I was kindly sent the Holbrook metric and BA gearing tables.

I can't however help you with your apron cross feed problem, I don't own one of these lathes but I do not imagine it is too difficult.

Regards Brian

[Stephen LeedhamParticipant @stephenleedham43090]

Have you still got the Holbrook lathe? I have the same model C8 electronic that I am slowly restoring.

The cross feed needs adjusting on the cone drive clutch with some simple to make pin spanners.

The saddle and apron are removed easily within minutes with care. Taper pins make removing the driving shafts easy. The stationary shaft is a mystery to me, I have made clamp blocks to hold it in place. Mine was loctite in I believe.

I run a 2.4Kw motor via a VFD it is pie feck and can run the lathe to 5,000rpm easily as it's 2 pole 3,450 rpm motor. The lathe originally had a 3hp DC motor driven via a three phaze convertor setup. It takes .050" per side cuts with easy in steel. Although being a toolroom lathe I suspect it is not supposed to take such deep rough cuts.

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