Alfred Herbert high speed bench drill

I have just started renovating this drill. It isn't the common high speed bench drill that one normally finds, if you google the above title. I believe that this one is an earlier model, probably pre war or wartime manufacture. The main spindle is supported on a vertical sliding surface and fastened there while the quill can be used in the normal manner via an adjustable lever. The setup is very similar to the much more common Pollard drills

Now the problem is this. It has a notice listing its speeds. It has 6 speeds ranging from 2350 rpm to 12,000 rpm. Lifting the belt cover reveals a block of 3 flat pulleys on the motor with equivalent pulleys on the main spindle, there is a very thin, wide belt transmitting the power. It still has its original massive motor which is a 1/3 hp, 2880 rpm three phase. The motor is specific to this drill and a massive mounting arm is integral with one of the motors end covers.

So my query is how does one get 6 speeds with this set up? There appears to be no reduction gear box on the drill, if there is, then it is mighty small and no lever to change gear! I was expecting a 2 speed, three phase motor, such as a Dahlander. The rating plate shows the current to be 0.6 amp at 400 / 440 volts. There are only 3 wires going into the motor, which rings alarm bells. I would surmise that it is wired in delta as there is no sign of a neutral, but then the motor is stated to be 400 / 440 volts NOT 240 volt 3 phase as I would expect with delta connection.

There isn't a terminal cover plate on the motor, the three wires just go through a grommet on the motor casing. Next move will be to dismantle the motor and see what is there. Not easy, as I can barely pick it up!

Does anyone know how you get 6 speeds out of this oddball?

Regards,

Andrew.

Edited By Andrew Tinsley on 06/03/2021 15:04:40

Hi Andrew,

The motor is 440 three phase ! But I recall a similar high speed drill that had an extra pulley, so you could swap the motor one. The motor was adjustable for distance to account for the change in pulley size. Might have been an Alfred Herbert one. If it is the one I'm remembering, the chuck only went up to 3/8", tiny little thing.

The Meddings high speed drill has additional pulleys to implement more speeds, the pulleys are quickly released with a thumbscrew and the pulleys are a light push fit on the shafts. Could the Herbert have a similar arrangement?

Mike

Please ignore my comments about the motor being wired in Delta! A case of brain fade! It is connected in star, goodness knows what I was thinking of when I said it must be connected in delta!

I don't fancy digging to find the star point on this one! If I mess up the motor then I have a fair bit of work required to get a new motor in there. it is either a rewind to get it connected in Delta, with modern insulation or a cheapie 440 volt inverter. I swore I would never buy a Chinese inverter, but maybe this is a worthwhile occasion!

Thanks,

Andrew.

Invertek inverters start at £95, I don't know why anyone would even consider buying spending £60 on something of dubious quality when for little more you get a lot more.

Has any one actually had a Chinese inverter of dubious quality. I often read on HERE, a lot of derogative comment regarding Chinese made inverters, but, when I ask friends who have got Chinese made inverters, all say they work as expected and are very happy with their purchases. 20/25 or more years ago I fortunate as I able to buy some pre own inverters at knock down price, so no axe to grind. As so many car components are made in PRC or India are they also of dubious quality, I wonder. John

Firstly, to the op, it usually isn’t difficult to find the star point in a three phase motor - the first one I did was a bit daunting, but once you’ve taken the motor apart the worst bit is over.

I’ve got two Huan Yang vfd’s, both from China via eBay. The one on the lathe has been fitted for around five years now, and has always performed perfectly. I have another one on my cnc router running a 2.2kW spindle also works well, though I found out that it is a little susceptible to electrical noise from the controller and had to fit a small capacitor to the analogue speed inputs - total cost about £0.01. I have also found that Huan Yang use an unconventional Modbus standard, which doesn’t affect me at all as I don’t use Modbus.

So yes, I agree with John Fletcher - no reason not to buy a Huan Yang, especially if you just want to run a 3 phase induction motor. And I did actually look at buying something from a U.K. supplier - a 2.2kW model was £230, and apparently comes from Italy, and you can bet it is full of electrical components that come from China.

It's the safety aspect that's most important, I'm sure a Chinese inverter is fine, as long you buy it from somewhere like inverter drive supermarket that would only sell products that meet safety requirements.

Hello again,

I have converted a good number of motors from fixed star to delta by digging out the star point. This motor is very specific to the drill. Not just any motor, but one with a massive integral mounting arm. I want to keep the motor as it is original to the drill. If I mess up digging out the star point then to keep originality, it is a rewind job (to delta) and that isn't cheap!

Show me an Invertek inverter that has single phase in at 240 v and 3 phase out at 440V for £95 and I will buy it. You must know such inverters cost an arm and a leg!!!!!!!!! The only cost effective inverter at this spec, will be a Chinese one! I don't buy Chinese inverters but stick to European ones, but in this case I will give it a try, cheaper than a rewind.

Andrew.

I dont know if your drill is like my old J & S on this machine you swop the quill pulley for the motor pulley.

Paul

Hello Paul,

That did occur to me! I have just measured up the pulley diameters and was going to work out the speeds if one did just that. I will report back.

Thanks,

Andrew.

Hello Paul,

Unfortunately it doesn't work out for  the Herbert drill. It looks as though I need to make a new triple motor pulley at twice the existing diameters. There is plenty of room to get this in the existing set up. Which makes me think this was the original intention, as otherwise the pulley guard could have been made much slimmer for the existing motor pulley

Thanks,

Andrew

Edited By Andrew Tinsley on 06/03/2021 21:26:43

Andrew,

On my Flott high speed bench top drill, the pulleys are easily swapped over, a pin spanner releases the pulley from a slotted taper.

Dennis

Hi Andrew

I have an Alfred Herbert Model B high-speed drill, and as-made it should have come with three interchangeable motor pulleys. These are secured by a LH thread stud onto a tapered shaft on the end of the (single phase) motor. When I bought mine it only had the smallest pulley - giving the slowest spindle speeds.

The pulley on the spindle is two-step, as should the interchangeable pulleys be. I calculated what diameter motor pulley was needed to give the intermediate and high speeds - I didn't bother with two-step - and turned them from multi-step aluminium pulleys, as used for pillar drills and the like. I put a crown on the pulleys to make sure the belt stayed on-centre.

The other issue is one of belts: you need a different length belt for each pulley - there's insufficient adjustment on the motor to allow for changing the pulleys. I got my belts from a very good company in Gloucestershire - can't remember the name I'm afraid, but they were no huge problem, and I bought two of each size, which will see me out! If you would like photos just shout.

David.

Mike, do you have one of these, with the original extra pulleys?
If so, would you mind measuring them for me please.
Thanks

Bill

Hello David,

Thanks for the info. My drill is definitely 6 speed with 3 step pulleys on both motor and spindle, so it is a different model by the looks of it. I need to turn up a new high speed pulley ( the pulleys are changed on the motor for low and high speed range). My available lathe has too small a centre height to accommodate a new high speed pulley, so I need to wait until I can use a friends lathe.

If you can give me any more information on belts I would appreciate it, mine is approx 20 mm wide and is a very thin flat belt. I have about 125 mm adjustment on the motor position which means I can use one belt size for both high and low speed pulleys.

I have finished mechanical work on the drill and just need to rewire it. After sweating blood, I managed to change the 2800 rpm three phase motor from star to delta. I must have done this for at least a dozen motors, but this one was very difficult to get at the star point and the winding insulation was in a delicate state! Amazingly the motor ran on an Altivar 28 VFD. I suspect the motor won't last too long and when it fails,then an expensive rewind will follow!

It has been in a dismantled state for so long that I had forgotten how massive it is. I bet it easily outweighs my Centec 2B. I don't expect that it will be used much but I didn't want it to go for scrap.

Regards,

Andrew.

Edited By Andrew Tinsley on 03/05/2021 13:27:39

Hi Andrew

On the basis that a photo is worth a thousand words, I've uploaded some pics of my machine, which I suspect is smaller than yours (!).

next pic is with the cover off, and shows my home-made second size pulley in place on the motor spindle (the tall central spindle is the rise and fall mechanism for the head casting on the pillar).

This shows the taper stub on the end of the motor shaft, onto which the chosen pulley is bolted...

...and these are the three pulleys. Original cast-iron bottom right has two options, whereas my home-made aluminium ones only have a single step option.Turned the internal taper on my Emco Maximat V10P.

The other side of the three - the large one betrays its origin as a multistep pulley!

Lastly two of the three belts. These are the medium (740mm) and long (835mm) belts. Any decent belting/bearing supplier should be able to source them for you. My belts are significantly smaller cross-section than yours - 10mm wide by 1.1mm thick, but the same principles would seem to apply. My machine came into my old shop - The Tool Box in Colyton - some years back, and I had promised myself a high-speed drill if one ever came in: I model 0-gauge railways, and for drilling small-diameter holes (down to 0.35mm or so) it is incomparable.

Hope all this rambling has been of some small help! Best of luck with your own project.

David

Thanks David,

Mine is a totally different machine, I really must get a picture and find how to post it. The belts however are the same style as the one I have.

I will have to use an engine crane to shift mine. I think it must be well over 100 kilos.

Andrew.

Hi David,

Your drill certainly looks the bee's knee's, and the photo's and tip about acbelting (from another topic?) certainly are useful to me at least.

I also picked up a Type B in September, thoroughly coated in grease and brass chippings from it's hard working life, though mine only came with the largest pulley rather than the smallest. I investigated getting spares from HerbertSpares, but the price was a little eye watering...

I'm also interested to see that Herbert did actually supply these drills with single phase motors, the ones that I have managed to research either had the three phase motor, like mine, or have had a single phase motor retrofitted, like I am trying to do. I'd be interested if there is any other makers marks on the motor? The Gryphon motors aren't exactly an good fit on the back motor mount.

Next step for me is to make a new motor pulley cone - to fit the keyed motor shaft rather than the tapered pin.

Best Regards,

Chris.

I have the same HERBERT B drill. several pulleys 3 belts and even a handbook. I will try and scan, it's a fine machine. but very heavy. I rebuilt it 60 years ago and had new pulleys and belts shipped out to Canada from the factory

I paid 5 bob for it.

David