CovMac Lathes

CovMac Lathe resume - 17/10/2014

The big move of the CovMac might finally happen next week - headstock and bed in two parts. I decided to complete de-concreting tailstock legs after lifting the bed off. The fillet of concrete under the tailstock legs is so complicated, with legs two inches off the ground, and with a series of loose bricks, too, beneath, within a very hard, stony concrete mix, caution is the better part of valour here. Access is so limited, too, with lathe bed still in place. Were the legs steel, I would have done it, but with cast iron, I have been ultra-cautious.

In the meantime, I have begun renovating the first piece - one of the original CovMac chucks, circa 1940, (of which I got two with the lathe - plus two more modern Burnerds, smaller) a big, heavy four jaw.

Any advice as how to do this job best will be gratefully received. I attach two pictures showing interior and exterior. This chuck was quite diggered in rust, when I got it. So far, I have just liberally doused it in WD40 - three of the jaw screws now move a bit, fourth is still solid. Two backing plate screws are now loose, two solid.

I need engineering input as to application of heat on a chuck - I feel this might need a bit to free all threads. Might I spoil a chuck's temper by heating it, or over-heating it?

The chuck reverse, or interior, shows original CovMac paint colouring, a dark grey. I will restore the lathe to this colour. I think it might match Paragon enamel Colchester dark grey raven. I have some flecks of my original to send to Paragon, to get a good colour match.

I presume this is a non-scroll chuck, with independent chucks? What is the faceplate on the back going to reveal beneath it?

Apart from one chip which has come off part of the stepped jaws, bottom left in the picture, I can see no obvious damage - just a lot of rust and oily crud.

Many thanks.

Chris.

Edited By CHRISTOPHER MILLS 1 on 17/10/2014 08:51:35

Edited By CHRISTOPHER MILLS 1 on 17/10/2014 08:53:51

Cheap malt vinegar worked for me when removing rust and scale. It munches the guffy bits faster than the metal and creates a sort of goo, check it once a day wearing rubber gloves and scrub with a toothbrush until the object is clean then rinse off and dry

I used various sized basins for the bits on my ancient pultra and submerged them completely

Don't forget it, check it every day or twice a day, it's messy and time consuming

Done properly/carefully, an amazing amount of the original detail can be brought out and preserved from apparently knackered bits of metal, micrometer dial etchings etc

I don't advise scrubbing hard with brillo pads etc, too abrasive, let the vinegar do the hard work and scrub lightly

gl

Edited By Ady1 on 17/10/2014 10:07:50

Edit: you will also probably get some pitting (small holes) where the vinegar finds scale and deep rust

Edited By Ady1 on 17/10/2014 10:15:58

Or cheap 'everyday' cola.

Neil

Good news about the move Chris, I await the photos with baited breath!!

Phil

Thanks, gentlemen - I have also heard that cider vinegar is effective, but it is expensive to buy.

I am making my own, from apples on my allotment, but it will not be ready for 6 months.

Chris.

Chris,

I don't have anything to offer on the lathe move other than to stand back in admiration!

On the rust removal front though I've used the old gunsmiths dodge of a warm solution of common or garden Boric Acid. Make it up at about 30 gram per litre in tepid water and immerse the part. It cuts through all manner of crud and does a super job of de-rusting,.

Like all of the acid based processes it will leave a layer of black carbon on the surface that has to be removed and the surface will be very active and subject to almost instant re-rusting. After the rust is gone I do a rapid rinsing job with the part under water in an old plastic bowl and then dump it in de-watering oil. You can then fiddle about swabbing off the carbon with no fear of re-rusting.

Boric is safe, easily available and dead cheap.

Eug

More expensive, but very good

http://www.bilthamber.com/corrosion-treatments/deox-c

...see "how to use" tab

COVMAC UPDATE

Finally, some real progress on moving my CovMac from Southampton - the job was badly delayed by tailstock legs being deeply concreted into the floor - shown above. Basically, the previous owner had compensated for a fall in levels in his shed by placing its tailstock legs into a broad, shuttered bath of raised concrete. And it was a very solid and heavy mix of concrete. 

I scratched my head, and pondered my own innermost futility, on two visits, messed about with hammers and chisels, and hardly dented the problem.

This was not successfully approached until I had full faith in my engine crane of 2 tons capacity.

Trying to free the legs, with weight of lathe bed still on them was just impossible. Access was very limited, and the drip tray was much in the way. It was not until I had removed the headstock, and came to shackle the crane up for a test lift of the main bed, and I had not to lift the bed by much, to have the sheer weight of  tailstock legs actually free themselves from the ground - (I think they weigh over 100 lbs - I could only just carry them to my car). I tumbled them out backwards. 

This was a great leap forward. I enclose shots of the culprit. Once out of the ground, the concrete was simply knocked off with a lump hammer. It was such a huge problem in situ. It was very easy once out of the ground.

The big move is due next week. I will post many more pictures, when I have them downloaded from my camera phone.

I now have five pieces - headstock, headstock plinth, main bed and drip tray to move.

Lifting the main bed off its legs and down to ground level was, as Phil Whitley predicted, a little bit "hairy" but I managed it okay. It was very headstock end heavy, for I had accidentally jammed carriage & apron near the headstock end, and the tailstock rose three feet in the air above it. 

The crane was magnificent, and the lift was very stable, aside of the bed, when being lowered, wanting to roll forward onto the apron and screw-cutting gearbox. I managed this using a bar through the eyehole under the headstock, and chocking with wood. 

I used twin slings, each of 2 tons rating, through a piece of straight bar in the jib of the crane.

It is a real relief, for a novice, to have it all at ground level. Suffice to say, I have never lifted something this heavy before. 

I have broken nothing on the lathe, and have not hurt myself, either.

Am presently finishing building the necessary pallets to get the big beast out to the road.

All in all, I think the weight estimated for this lathe, on Lathes.co.uk @ under a ton, is a significant under-estimate. 

Tailstock, headstock, tailstock legs, headstock plinth, motor plate and motor are all really massively heavy items.  I am beginning to understand Neil Wyatt's use for it of the word "behemoth".

I think, altogether, that this lathe actually weighs about 1.4 tons.

All input, help and encouragement from you engineers has been worth its weight in gold. I really have appreciated being welcomed into this forum. Many thanks.

Chris.

Edited By CHRISTOPHER MILLS 1 on 12/11/2014 10:39:36

Well done, Chris !!

MichaelG.

Edited By Michael Gilligan on 12/11/2014 12:04:37

Slightly off topic but Borax (a salt of boric acid) is an excellent ant poison. Dissolve a half a teaspoonful in warm water along with as much sugar as you can dissolve and put a few spoonfuls of the resulting syrup in a jam jar with a hole in the lid (keeps larger animals from devouring your bait). Place it on its side on the path the ants follow into your house, as close to the nest as you can. As soon as they find it, they stop coming in the house and cart it back to the nest to feed to the rest of the colony. It acts as a slow poison and will kill off the whole colony in a few days. For more drastic results, apparently you can tip a bucket of hot borax solution into the nest.

Works every time for me, is almost harmless to humans (we could sprinkle the stuff on our cornflakes without danger) and is available at many pharmacies. It is lifted out of the ground in the Mojave Desert and used to be used for water softening for clothes washing purposes. The solubility is about 20g/L and the LD50 seems to be in the region of 2g/kg of body weight. Some new age tree huggers even take it as "medicine". It's pretty safe, unlike the industrial artificial pyrethroids.

Murray

Edited By Muzzer on 12/11/2014 12:33:26

To undo the screws, try an Impact Screwdriver:- **LINK** (also available from other suppliers).

Or if you don't want to buy one of those, then a length of steel rod (the same dia as the screw head) is placed on top of the screw and given a "good whack" with a hammer, this should shock the thread loose.

Congratulations Chris,

Keep working safely, but this is building into a really impressive tale.

Borax works as a flux if you are stuck without any easyflo, or you want to braze (with real brass wire) at a higher temperature.

Neil

P.S. I have to wind you up with this pic (yes it IS a lathe bed and headstock!)

Edited By Neil Wyatt on 12/11/2014 18:13:40

Many thanks, gentlemen.

Neil - It is very most certainly handier than the CovMac!

What is it? What can you make with it?

One pleasing aspect of the CovMac lift, to me, a beginner, was my engine crane.

Now, I am on a very small budget to rescue this lovely old machine, and I have had to do it all myself. (My wife will not help!!!).

The only method of lifting was by engine hoist, and I bought mine on eBay for £117.

Now, for something so cheap, I had doubts, naturally.

Yet, the build quality of it is just great - the main piston is an 8 ton rated hydraulic press, and I have every faith that this thing can lift its rated 2 tons.

It coped with my lathe bed, no problem - and I think the bed is likely 1300 llbs. I did the lift working quite alone, and at no point did I think this crane was other than my best friend.

It was both smooth and predictable, both on raising, and lowering. It really was silky smooth.

It was beautiful!!

Here it goes in on its prey, like a Tyrannosaurus Rex: Grrr -

Hi Chris, I like the look of that engine creane, and I am glad it is all safely on the deck with nothing broken and all fingers present and correct. I think 1.4 tons sounds about right. When Steve at landylift was moving mine, the jib extended quite a bit in order to lift the machine clear at its balance point, which is why his 2 ton hiab was struggling a bit, although we didnt manage to set the alarm going, it was getting near capacity.. Well done!

Phil.

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.

And I think you are teasing us with the photos!

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.

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.

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.

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.