CovMac Lathes

[CHRISTOPHER MILLS 1Participant @christophermills1]

Thanks Phil – Really, I would not be where I am today without your incredibly helpful input.

On the stuck carriage – the threading half – nuts are disengaged. But the half-nuts lever is stuck solid.

I just could not back-up the carriage enough to get it re-engaged on the rack.

You are right – the engine hoist is amazing.

The price of these rises on eBay, for they were well under-priced at £117,

Chris.

[Phil WhitleyParticipant @philwhitley94135]

And I think you are teasing us with the photos!

[VicParticipant @vic]

For rust removal try:

http://myweb.tiscali.co.uk/andyspatch/rust.htm

I just use a small battery charger. The process works very well and won't remove metal unlike acids etc.

[CHRISTOPHER MILLS 1Participant @christophermills1]

Phil,

I am sorry – you are right, for key photos are still on my smart phone, and I have been too tight-fisted to download them, due to Vodaphone avarice. I shall conquer my miserliness, and post the proper photos very shortly.

You Yorkshiremen are very prescient, I know that much! Canny.

The only views I do not have are the main bed in the air, for I was too nervous to take them. Sorry.

I will post when the big lift occurs. We will organise some "right hairy" views, such as to impress even Geoffrey Boycott (Yorkshireman).

Chris.

[CHRISTOPHER MILLS 1Participant @christophermills1]

The above shot of CovMac's drip tray shows extent of this lathe – the tray is about eight feet long, and made of mild sheet steel. You can see the remains of a pumped coolant system, a collecting tank at the far end, and rising pipe in the left foreground, but those are the only signs left of it. We will likely never know its nature.

Phil – Are there any signs of a pumped coolant system on yours? I know it has the tank.

Below is the lathe bed, minus headstock, awaiting collection. The steel rod, run through the bed's eyehole, was my salvation when lowering the bed, on the crane, when it had a really snakey wish to roll over forwards onto the screw-cutting gearbox. CovMac engineers of 1940 were very thoughtful, putting that handling eye in. I imagine, with lathe fully complete, that this is its perfect balance point, with carriage and apron rolled up to the tailstock end. At the moment the carriage is stuck headstock end, because I forgot I had removed the gap piece, and I accidentally rolled the carriage too far left, when giving it an initial clean-up, and disengaged rack from pinion – no amount of persuading would get it back on again. It is stuck there until dismantling time.

The twin green slings, 2 ton rated, are visible – the left hand one is one metre long, and I looped it basket fashion down through the head casting onto the steel bar through the eyehole; in this manner, basket handle fashion, the sling is rated to lift four tons. (This was a confidence builder).The other, two metres, went around one of the casting's bulkheads to right of centre. This inner method was much safer than looping on the outside, because I would have had to protect lead-screw and power feed bar.

The whole worked beautifully, apart from tailstock rising, and significant roll-over forward impetus on landing. Both were controllable.

We all survived CovMac, me, slings and crane. I have huge affection for this lathe, now. I am beginning to get to know it.

Chris.

[Phil WhitleyParticipant @philwhitley94135]

Hi Chris,

From what you say about the carriage, it sounds like the carriage has dropped enough to jam the upper half nut at least partially into engagement with the leadscrew, which is preventing the carriage going back onto the rack, I am going to be Mr Pedantic and suggest that you try and get the carriage back onto the rack before you move it as the weight of the carriage is on the leadscrew/halfnut interface, and the bump and grind of being transported could damage it. If you place a block of wood across the bed where the headstock was fitted and then use a longish (2-3 foot) lever to gently lift the edge of the carriage whils also jiggling the half nut lever and winding the handwheel(two persons needed) it should go back on. If it really won't go back, after it is loaded on the transport, place a wedge under the carriage behind the handwheel, and tap another wedge in to take the weight of the carriage off the leadscrew/halfnut (this is also an alternative way of getting the carriage back on, as it may have fallen more at the front than the back. leadscrews/ half nuts are rare and expensive! Damn! I wish I didn't live at the other end of the country and/or wasn't so busy, Unfortunately I have been south of Watford twice this year already and my annoying Yorkshireman visa has expired!

Phil.

[CHRISTOPHER MILLS 1Participant @christophermills1]

Phil,

I understand everything you say, and will act upon it on my next visit. I am unsure the carriage has come far enough left to have actually tipped – I do not think it has, but I will ensure that all of your concerns are addressed. I agree about protecting a lead-screw.

I will be making one visit prior to the day of the big move.

Chris.

[Phil WhitleyParticipant @philwhitley94135]

Hi Chris, an example of the hole and bar lifting system used on a very heavy bit of kit!

Phil.

[CHRISTOPHER MILLS 1Participant @christophermills1]

Many thanks Phil – it is a very good, stable system. Certainly worked for me.

Partly due your cautions on carriage possibly impinging lead-screw, I am considering taking lead-screw, power bar and screw-cutting gearbox off before the main lift, in Southampton.

That way I can bring gearbox back to London for a winter project. (I will not be going to Yeovil much before the spring). This machine once suffered a major league crash which tore away 25% of an eight inch chuckface, and I fear there may be damage in the box – the seized A – B lever might not be unconnected. Although, I know the gearbox rotates okay, I have seen that moving.

We are reasonably sure lead-screw disconnects via a tapered pin on external attachment to the screw gearbox, and that the power bar is a grub screw or two onto a collar.

The tailstock end attachments are free, and with half nuts disengaged, and power bar in neutral there should be nothing in the apron holding them. I should then be able to with draw both out backwards off the tailstock end?

Only caveat I can see on removing the screw gearbox is that access to the two lower bolts (the ones you cannot see) is limited – I think I have to remove the bottom sump plate, and access those from beneath. My reach there is pretty limited. I only have a couple of inches beneath the box to play with spanners.

If you are anywhere near your own Covmac this weekend, I would very much appreciate any heads up on these aspects. If I do this, I am aiming to shoot for the coming Tuesday. Thanks.

Chris.

[Phil WhitleyParticipant @philwhitley94135]

Hi Chris, I will be there Monday, and will have a look.

Phil

[Brian WoodParticipant @brianwood45127]

Hello Chris and Phil,

We are clearly all now on the same wavelength having corresponded separately by email, gentle steps all the way.

You are right I think Chris, the lower bolts in the screw cutting box are hidden inside, Tony's website picture suggests that..

Brian.

[Martin WhittleParticipant @martinwhittle67411]

PM sent

Martin

[CHRISTOPHER MILLS 1Participant @christophermills1]

Hi Martin,

Sorry, but I do not understand your post.

Thanks.

Chris.

[Martin WhittleParticipant @martinwhittle67411]

Hi Chris

I have sent you a Private Message which you should receive on your usual email account, offering help if you need it while moving your machine (I live close to Southampton).

Martin

[CHRISTOPHER MILLS 1Participant @christophermills1]

Dear Martin,

I do not know how to access your message, as it does not yet appear in my box, in this site, or in my gmail account, but I do very, very much appreciate your offer of help in Southampton.

An engineer in attendance, next time I visit, would be like pennies from heaven.

My lathe is in Totton.

Best wishes, and many thanks for contacting me. I look forward to hearing from you further.

Chris.

[Neil WyattModerator @neilwyatt]

PMs don't go via email, there should be a flashing envelope in your 'my friends' box at top right (where your profile pic would be, if you had one).

You can also click 'messages' on the top bar.

Neil

[Brian WoodParticipant @brianwood45127]

Mystery solved, Martin PM'ed me instead!

I've copied it and sent it on to Chris by email, and thanked Martin on his behalf

Brian

[CHRISTOPHER MILLS 1Participant @christophermills1]

Martin,

Tried you on your home phone, but got an unobtainable tone. WiIl try later on your mobile.

I will be in Totton on Tuesday, from about 9 am, and I would be greatly appreciative of any help on the day.

I want to try and remove the screw-cutting box, and take away, if I can, all but the headstock and main bed.

Many thanks. Speak later.

Chris.

[Phil WhitleyParticipant @philwhitley94135]

Hi Chris, Brian and Martin,

Hope these pics will help,

Phil

Half nuts disengaged.

Half nut engaged, but I note that your lever is in a different position to mine on the shaft, so I will add "move clockwise to engage the half nuts with the lead screw, anticlockwise to disengage"!

Lower fixing bolt, you can see half of it peeking out from behind the selector lever/spindle

You can see all of the bolt head here( rusty blurry as it is!), with the selector moved to the other end, you may be able to get a socket onto it with a ratchet and a universal joint, but you cant get to the right hand one anyway so it will be best to remove the bottom plate.

Hope this helps guys! I had to go for some firewood then I forgot which way round the lever worked, so I had to go back again, but I have had a message to say that Richard the joiner is coming in the morning (Sunday!) to fit the new front door and frame, which is excellent, so I needed to check if I had enough cement, know what I mean!

Phil

[Brian WoodParticipant @brianwood45127]

Hello Phil,

What useful information, it knocks my theory on the head regarding a bolted on 1/2 nut engagement lever being bolted too tight. There must be some other reason for that lever being locked as it is.

Chris confirms the 1/2 nuts are open.

Best wishes

Woody sorry, Brian here!

[CHRISTOPHER MILLS 1Participant @christophermills1]

Phil,

Many thanks for this: I am so very sorry that you become dogsbody/gofer in this business so often, because you have one of these machines, and I make you run around, but your information is always absolutely worth its weight in gold.

Your combination of words and pictures is film industry standard!

You will get your rewards before you reach heaven!!

I cannot believe a camera can see right to the lower bolts, but there they are!

Interesting to see red oxide paint in the screw gearbox interior.

Good one Phil. Have a great weekend.

Best regards.

Chris.

[Phil WhitleyParticipant @philwhitley94135]

No problem Chris, any excuse to play with "toys" and I'm there! The camera is really nothing special, it is an Acer solid fun CL6330, but I do use the macro setting for close shots. The problem with the fixing bolt shots is that it is dark inside the gearbox, so the camera cannot "see" enough to focus properly. Also checked my new outside auto lights while I was there the second time, first one comes on as I park the car, second one as I arrive at the door……………..Perfic!

Phil.

[CHRISTOPHER MILLS 1Participant @christophermills1]

Thanks Phil.

Much appreciated.

Electrically, what might I have to do to my CovMac's motor?

Best.

Chris.

[Phil WhitleyParticipant @philwhitley94135]

If you send me a pic of the motor, or post one up, I will be better able to tell you.. Basic stuff, as it has been unused for some time, put it somwhere dry and warm if possible, to thoroughly dry it out. Spin the shaft whilst listening to the bearings with a long screwdriver, metal end on the bearing, handle placed onto your ear (not a joke, you will be amazed what you can hear). If the motor is totally enclosed, give the bearings a couple of shots with a grease gun. and then get it "megger" tested to check the integrity of the insulation. If the motor is a vented frame, have a look through the vents for dust, dead mice etc, and blow through the vents with compressed air to clean it out.

Phil.

[CHRISTOPHER MILLS 1Participant @christophermills1]

Phil,

Thanks.

There is a clear picture of my CovMac's motor on page four of this forum thread. It does have a ventilation grill, and I hope there are no dead mice in it. There will be spiders.

I do not much fancy electrocution, so the motor's integrity is of interest to me.

In terms of bringing it up to modern safety standards, I do not want to have to bolt anything obviously 21st Century to the lathe, to spoil its antique looks, but I will want it 100% + guaranteed safe to use.

I shall save the Startrite box on the wall, but that will just be as a souvenir?

Chris.

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