CovMac Lathes

>ROAR OF APPLAUSE<

Congratulations to the team!

I bet the big challenge will be getting that chuck off

Neil

Thanks gentlemen.

Neil, the chuck you have assessed spot on - I have no real idea yet of how it comes off, despite Phil Whitley and Brian Wood both trying their very best to elucidate for me. I cannot find a spindle lock mechanism, as yet.

Final Note - Moving the CovMac - To go back to the beginning, here is reminder of the lathe as I took it on. After spending perhaps all of 18 months looking for a suitable, old metal lathe to restore, this was my first choice:

And t'other end:

The 2x2 timber is holding the roof up, and sheer amount of general neglect, and filth, are plain to see. Sadly, it seems the previous owner, a professional engineer, who died in 2012, aged 84, was for long, owing to age or infirmity, unable to give the lathe the TLC it needed. That this wonderful industrial sized lathe spent its last 30 years in a filthy old garden shed is a wonder to me.

CovMac Goodies: - With the lathe came a truly amazing storehouse of accessories and tools - five chucks, five face-plates, including the monster 24", a stout centre-steady, a number of gear change wheels, enough cutting tools, drills and boring bars to last me two lifetimes, 50 metal files, two 6" Record engineer vices, an anvil, taps and dies, dozens of hand tools, wrenches and pliers, and a selection of specialist items yet to be identified, one small vernier and an Ape Microball, and the previous owner's signed copy of "Machinery's Guide" - 1942 - very contemporaneous to the lathe itself . Plus, I have a hefty selection of metal bar material. It took three trips in my VW Passat estate to remove it all.

Thus, I reckon I may have enough to begin a bit of metal turning!

This started out as a museum project, from which I hoped to learn some engineering, and it has worked extraordinarily well, so far.

This 11 weeks which has elapsed, since I took on the lathe, has been expedited by the amazing generosity of heart shown me by members of this forum. It has been so heartening to get such help.

I have to return to my own professional commitments, presently, but I will begin the thread again, in the New Year, with restoration of the machine, which has already begun in small parts.

I will be doing a bit more research into Coventry Machine Tools Limited - there is little known on the firm so far. They were never primary lathe specialists, but better known for their heavy forging machinery. Their dates seem to be about 1936 - 1953. There is some material in Coventry City Archives, which may throw us useful light. There are known but 5 surviving lathes made by the company - one is in Australia, the only known 17" head example.

Might I wish all you engineers a Merry Christmas, and a Happy New Year, 2015.

Many thanks.

Chris Mills.

Edited By CHRISTOPHER MILLS 1 on 07/12/2014 13:09:49

Hi Chris, well done to you, and a Merry Christmas to all! Don't worry about the chuck, it simply unscrews from the spindle anticlockwise, looking at the chuck face, top of the chuck goes towards the operator. If you get a large adjustable spanner and put it on one of the chuckjaws with the lathe in low gear and PULL! it should come off. Shock (hit) it with a piece of wood if you have to. If it doesnt move you can put a blowlamp onto the boss at the rear of the chuck, just to warm it, we are not talking serious heating, just enough to release the grip by getting the boss to expand slightly more than the spindle, then try again. remember the chuck comes tight against the flat face of the register, it does not get ever tighter on the thread. If you look at this pic again you can see the nose thread, with the register behind it, and the flat face that the chuck backplate tightens up against is visible just in front of the bronze bush. My chuck looked like it had been on for ever, but when I at last put an adjustable spanner on it, it unscrewed quite easily.

Phil (Bah! Humbug!)Whitley

Hello Chris,

I too would like to add my congratulations on the recovery and removal to Yoevil. It has been a very big job which would test many of us on this forum and to take it on as you have done with a declared minimum of general engineering knowledge and understanding is truly worthy of salute.

I join Neil in the roar of applause, some of which must surely go in the direction of Martin Whiitle who arrived on the scene like a white knight at exactly the right stage. Well done both of you and not even a fingernail broken.

You may already have spotted the thread above this one regarding the anvil, I know your's isn't full size but it gives you an idea of current value and with all the other goodies that came with the lathe I think we can all say 'the boy done good'.

Your appreciation is received with due gratitude, but it was clear to a lot of us that you needed the collective input from years of experience and I think the result justifies the effort.

Phil is quite right over the chuck removal, the lathe is already in awe of it's new master so it will obey!!

Brian

Phil - Many thanks.

Brian - Spot on - I had jumped feet first into a deep hole - but I knew I must not dig it deeper, but earnestly appeal to those who might help me back to the surface.

My first post on this Forum, effectively, was shouting, "HELP!"

Looking back on this thread, over its fourteen pages, I simply cannot believe how much I had to know, how much practical information, and some severe cautions, I needed to absorb, and quite quickly, for I had not unlimited time in that shed at Totton - and how much wisdom came my way, in time, from those in the know. This was a form of magic.

And the saved and rescued heritage of the CovMac is the beneficiary - and that I hope I have a few more friends than I possessed three months ago.

That Martin lived just around the corner was such a huge bonus.

A whole round of beers will be on me, when we can all meet up!!

Best wishes to you all.

Chris.

Been great watching this thread...

Just in case anyone else fancies having a go at a Covmac, a look here might be of interest!

I have no connection with the seller BTW, just happened to spot it and thought it might be worth a mention here..

Many thanks, BikePete - It is of great interest.

Pete's link is to a 17" geared head CovMac up for sale presently on eBay for £750. It is in Mansfield, Notts.

This is one of only two known surviving 17" CovMac lathes - the other is in Australia. (I am trying to post a photograph of the Aus example on this site, but it does not like my presently formatted Jpeg.)

This one on eBay is missing its gap piece, and is indescribably filthy, but apart from that quite vital missing piece, it seems otherwise all there and original. It has kept its wooden clutch pole.

lt would be nice to think that somebody out there will have some commitment to saving this one - but its sheer size, at 2 tons, and with Three Phase power, might yet doom it to the scrap-heap.

I have my work cut out with my own, but there will be lots of intellectual support offered to anybody wanting to take on this one.

There are presently known just 6 surviving CovMac lathes - one belted head 13", three geared head 13"s, and two 17"s.

Interestingly, the two 17" examples appear originally presented in green - not the uniform dark grey of 13" models.

Edited By CHRISTOPHER MILLS 1 on 17/12/2014 06:56:57

Here is a 17" CovMac, very similar to the one advertised on British eBay presently - this one, which came with loads of chucks and face-plates, which can be seen in the picture above the lathe, sold in Australia in 2013 for 500 Aus dollars - in other words, very little money.

It is broadly similar to 13" geared head models, but much, much bigger - reputedly twice the weight of a basic 13" CovMac model.

It is about 2 tons of lathe.

The bed is a much chunkier monkey. Other than that, they did not radically differ from mine and Phil Whitley's.

Headstock, screw-cutting box, carriage, apron and tailstock are all very much the same - it also had the clutch, with wooden clutch pole, just like the smaller models.

Just to give some scale to this, and it maybe even larger on this model, but the taistock barrel on the 13" lathe is a trifle over 1.75 inches in diamater; it is threaded 4 TPI with a square thread. The barrel itself is 18 inches long, it looks nothing like that in the picture above.

Brian

Edited By Brian Wood on 17/12/2014 15:40:54

Perhaps he should get a ManSon next:

Neil

Edited By Neil Wyatt on 17/12/2014 16:40:51

Neil,

Never put your lathes on a boil wash! I would not.

No, it's the tumble drying afterwards that does the damage! What a nice model Neil

Brian

That's not a model - or a toy!

Look up the ManSon on Lathes.co.uk - it was a proper, well made small lathe, which had some nice accessories.

Neil

Sorry Neil, I hadn't come across them before.

An outstanding piece of work, very desirable indeed.

Brian

Neil, that's a nice little lathe. I see it does not have the on/off, and reversing switches, have you got the motor, and foot control?

Ian S C

It'll be perfect with CNC fitted, and DRO's on all axis.

Now the CovMac is safely under the Christmas tree, might I wish all you engineers a very Merry Christmas, and a Happy New Year!

Many thanks for all your help in 2014. It was a very great deal appreciated.

I've not posted in this thread to date but have been involved with Chris's COVMAC lathe assessment and move since being introduced via a mutual friend.

I've been working with single and three phase induction motors for very many years but finding this one with 5 power connections and a separate controller was a new one on me and also a couple of friends older than I.

I now have the motor and controller on the bench and had some time to investigate it thoroughly.

There are a total of 6 terminals each going to the ends of 3 three separate windings. One of these is the Start winding marked Z1 and Z2 and the other two winding are both used for Run A1-A2 and A3-A4. It has no internal capacitor or centrifugal switch.

If you come across one of these motors then it is vital that a standard direct on line (DOL) starter is NOT used.

The regime for starting these motors is to connect the run windings in series and momentarily connect the start winding with a series capacitor in parallel with the run windings. Once the motor is up to speed, the controller disconnects the start winding AND switches the run windings from series to parallel.

As far as I can tell, this series parallel switching is there to keep the starting current reasonable. Even so the peak start current on this motor (3HP) is 34 amps before settling down to just over 10 amps once running.

Full load current is specified as just over 13 amps.

I will be supplying Chris with full documentation of the motor and controller. If there is interest here, I can publish it here too if I can workout how to insert files.

Cheers

Bob

Edited By 9fingers on 27/12/2014 17:06:39

Hi 9fingers, I would be interested to see the motor/ starter sort out! This is why I emphasised to Chris how important it was to get the original starter with the motor. It is an AEI Stayrite, and looks like it is the right one for the series parralell capacitor start. I have been in electrical engineering since 1967, and although these were not common, we did used to meet them on things like original Heidelberg printing presses which had been fitted where 3 phase was not available. There is nothing similar in my "Brooks" motor book, but I gather Chris marked the terminals when he disconnected the motor from the starter, so it should be a matter of servicing the starter and reconnecting as was. Capacitors in these installations are sometimes fitted in the starter itself, and switched in when needed. In the meantime I will have a rkae around my old paperwork and see if I can come up with any diagrams.

Phil

Bob and Phil - Many thanks - and Happy Christmas to you both.

So, I can see now that the previous owner of my CovMac was just about managing to run it on a 13 amp plug, on its 10 to 13 amps normal running range, but how can his house electricity, on a 13 amp plug, have coped with 34 amps starting power?

When his son tried to start it, for me to see, on my first viewing, it blew the fuses, and he tried again, to no avail. It blew twice.