CovMac Lathes

[CHRISTOPHER MILLS 1Participant @christophermills1]

Ady1, many thanks for that, I had imagined a gap piece impossible to fashion, – but then there is my wife to consider, too – I have survived CovMac 1, so far – CovMac 2?

Different kettle of fish.

 

Edited By CHRISTOPHER MILLS 1 on 11/01/2015 13:19:45

[Brian WoodParticipant @brianwood45127]

Hello Ady 1,

Chris and I have had discussions over the missing gap piece, I agree with you but only so far in that the surface would have to be completed with the piece fitted and ground along with the bed as a finishing operation; that operation would just not be possible in my view as a retro fit on a substitute without a full bed regrind as well.

It is a shame really, just a bit of carelessness in a past move and a vital component gets left behind.

I have seen decent machines in bankruptcy sales with accessories dumped in a grotty box and work still in the chuck, tools loaded ready for the planned operation, even the previous swarf is still present. The Receivers are only concerned in achieving a fast sale to move the job forward to site sale and the niceties of the machines/tools or whatever in terms of completeness mean absolutely damn all to them and those chosen to flog off the carcase.

I can just imagine the feelings of those blokes losing their jobs at lunch break 'Don't bother coming back, cards in the post'

Regards

Brian.

[BikepeteParticipant @bikepete]

At the risk of flogging a dead horse, has it definitely been confirmed by the seller that the gap piece is missing, and not somewhere on the floor/in a cabinet/on a shelf somewhere?

[CHRISTOPHER MILLS 1Participant @christophermills1]

Yes, the gap piece is lost – I asked him.

[John LapthornParticipant @johnlapthorn83182]

Hello Everyone,

I have read this thread with interest. I have to admit that my main interest is that I would appear to own one of the THREE remaining 17" Covmac Lathes. Mine was built by D & J Tullis Ltd of Glasgow and is fitted with the usual "war finish" plaque.

Here come the pics……………….

John

[CHRISTOPHER MILLS 1Participant @christophermills1]

Hello John,

Many thanks for the posting. Yes – we know of just the 6 surviving CovMacs, three 13" and three 17".

Mine is partially through being renovated – simplicity of the engineering is impressive. The screw-cutting gear-box needed comprehensive work – it is in the capable hands of Brian Wood.

Have you ever had any of yours apart?

Can I please see a close up of the sliding/surfacing control boss – it looks very different to mine. 

Do you think your paint finish is the original?

 

 

 

Edited By CHRISTOPHER MILLS 1 on 31/03/2015 14:37:32

Edited By CHRISTOPHER MILLS 1 on 31/03/2015 14:38:20

[Phil WhitleyParticipant @philwhitley94135]

Hi All, That paint looks to be the same colour as mine is painted, but mine has a different maker, and was reconned by Berridges, who I always assumed had painted it that colour. looking in the plinths however, it looks like it got one coat of red lead primer, and then the magnolia gloss, which has yellowed over the years. Mine looked just the colour of Johns before I cleaned it. Hi John, BTW that is a magnificent looking machine, I have the 13" Geared head model like Chris. Do you use it regularly, and what do you use ot for? Good pics BTW

Phil

[Phil WhitleyParticipant @philwhitley94135]

John, where are you in the UK?

Phil

East Yorks.

[John LapthornParticipant @johnlapthorn83182]

Hi Phil & Chris,

Chris: No, I have never had it apart and I believe that the original colour was an off white. The current colour is called buff and was applied about 30 odd years ago by the previous owner. The surface/sliding knob is a modification made by the owner before the previous one. It is really handy as sometimes the knob can be quite hard to turn once the load has been on it for a bit. Pic to follow.

Phil: I am afraid I don't use it as much as I should. I do repairs to small ships and boats for a living so it comes in handy occasionally. I am in Kent.

For interests sake D & J Tullis Ltd manufactured industrial washing machines!

Regards John

[John LapthornParticipant @johnlapthorn83182]

[Phil WhitleyParticipant @philwhitley94135]

Hi All, Like the handle mod John, saddle is the same as mine. It looks clean for it's age, and the bed well oiled and bright, glad you still use it and enjoy it.

Phil

[CHRISTOPHER MILLS 1Participant @christophermills1]

John,

Many thanks – where in Kent are you? I have family in Canterbury & Folkestone, and I appear periodically.

I would love to see this lathe of yours, some time.

I thought your sliding/surfacing boss was an adaptation, and it has set me thinking as to how I renovate mine – mine took a lot of abuse on the knurling, and now I think it might best be re-knurled with extra grip in mind.

How long have you had her?

[Brian WoodParticipant @brianwood45127]

Hello John,

I am pulling together a book on gearings for lathes with screwcutting gearboxes, but there will be a sub section for the mini lathes that come without a gearbox.

As Chris has told you, I have been deep into the guts of the gearbox for his 13 inch Covmac and the relevant information gleaned will be included in the book. However, you have added a further dimension to the story with your 17 inch model and the obvious difference in appearance between the two models of gearbox.

Just to help me complete the record for these rare machines, would it be too much to ask you to post one or two gearbox pictures and a good readable picture of the threading table on the plate attached to your gearbox. Personally I can't see why the two boxes are arranged differently but there must have been a good reason for new castings and internal layout to be chosen. One outstanding difference, apart from the change in angle for the selector ramp is the absence of the outer cover linking the leadscrew and power shaft to enclose reduction gearing on Chris's model. And is there a metric chart inside the change wheel cover?

With your permission I would like to add anything of notable difference affecting ratios, the design and cosmetics are of interest but don't inluence gearings.

Kind regards

Brian

[John LapthornParticipant @johnlapthorn83182]

Hello Brian, here is a photo of the screw cutting / feed ratios, you may need to zoom in to read it all. I am afraid I forgot to take a couple of the gearbox so will do that after Easter. There is no metric table inside the gear cover.

Hope this helps.

Kind regards

John

[Brian WoodParticipant @brianwood45127]

Hello John,

That is a big help thank you, although I must confess, I don't understand the feeds table, quite different to that on Chris's gearbox.

The headstock spindle speeds are all bodily a shade slower, perhaps befitting the larger swing the 17 inch lathe brings to the work but the thread pitch results are identical between the two gearboxes, all the more puzzling then the different feeds. Clearly the internal gearing is identical in it's action but laid out a different way with your gearbox.

I look forward to more general pictures when you are next there week

I have also sent you a PM .

Kind regards

Brian

Edited By Brian Wood on 03/04/2015 14:33:31

[John LapthornParticipant @johnlapthorn83182]

Evening everybody

Here are some more photos of the 17" Covmac. The first one is the most interesting as I believe it shows the casting number "99" and the date 25 10 44. That means the poor old thing is 71 years old this year!

All I need now is a 127 metric conversion wheel and I gather a 40 tooth wheel to get another 14 different feed settings.

I must try and do an accuracy test over the full length between centres.

Regards

John

p.s. Brian, I have sent you a pm.

[CHRISTOPHER MILLS 1Participant @christophermills1]

John,

Fascinating – on which part of the lathe have you found this very crucial date?

It would be nice to think mine and Phil's may similarly be dated – I have not gone over mine fully yet, with a fine tooth comb, but I have found nothing remotely like a date.

[John LapthornParticipant @johnlapthorn83182]

Chris,

I found the date on the tailstock end of the lathe bed. Let me just say that I think its the date and casting number!

kind regards

John

[CHRISTOPHER MILLS 1Participant @christophermills1]

Yes, they are a date, John. I agree, 100%.

Mine and Phil's 13" models were both reconditioned in 1955, by Berridge in Leicester.

Mine was a War Office owned machine in World War Two.

It would seem yours escaped that reconditioning – it was on reconditioning, I think, that mine got all metric changeover information – two brass panels, on the back-gears' guard, giving all wheels needed, a huge number – 26 in all, I think.

Where are you in Kent? I would much like to see your CovMac.

[jim kirklandParticipant @jimkirkland56149]

Hello there. I was wondering if anyone could help me.? I have a stayrite starter box almost identical to the one discussed here. I also have the original single phase 3hp motor to go with it. Unfortunately the two have been disconnected and i have very little experience in this wiring this type of thing. The motor has 6 wires coming out of it red . blue , yellow , earth, and two black.

If i can get it up and running I will fit it to an old rand ingersol compressor i bought. It had a 3hp three phase motor but i dont have the twenty grand i would need to get threephase installed . Ive had the stayrite stuff for years can remember where it came from but i thought this was the perfect job for it.

Trying to post a picture , but struggling.

 

Edited By JasonB on 12/08/2016 20:18:02

[Phil WhitleyParticipant @philwhitley94135]

Hi this looks like single phase start/run type starter, can you post the details from the starter spec plate and the motor plate please, and also a pic of the motor, and the front panel of the starter.

Cheers,

Phil

[Phil WhitleyParticipant @philwhitley94135]

also a pic of the motor connector block would help!

[jim kirklandParticipant @jimkirkland56149]

Hi further pictures as requested. These contain all the information i could find on both the starter and motor. I don't think there are any other plates

[9fingersParticipant @9fingers]

I did the work on this stayrite starter for Chris Mills and it is written up in annex G to my motor paper.

Thanks to NTLworld withdrawing my free webspace, the new link to the paper is here

https://drive.google.com/open?id=0B_GZrXNsNxTlQzd6aldlQjJtUDQ

Identifying the winding should be easy. look for three isolated winding, two similar which will be the two run windings and one different which will be the starter.

Under the grey cover in the starter will be the capacitor(s). check that these and not leaking either chemically or electrically and if so replace with similar rated new ones.

hth

Bob

[jim kirklandParticipant @jimkirkland56149]

Thanks Bob .That was brilliant. I had a quick look at the relevant part of your paper and it looks perfect. i'm busy , but shall try to get the work done on it soon and shall let you know how i get on.

Cheers

Jim K

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