CovMac Lathes

[neville rigg 2Participant @nevillerigg2]

Hi Chris, I trust that you are not going to use the shakle on the rope as the pic suggests, Get two slings and put the eyes on the ends on thee hook of the lift, the way you have it the rope is very likely to slip if the load is not evenly balanced, looking at the machine I get the impression that it is going to be heavier at the headstock end you would be much better with slings, these are available in various lengths and it may be easier to have two of different lengths in order to balance it better.

A engineer supply company would be your best bet to obtain them and if you grovel you might be able to return them if they have not been used, check it out first, they may have skates for hire if your lucky.I used to remove and re-install ali extrusion presses which are a little bit heavier but the basic peinciples are the same, just take it slowly.

Neville.

[CHRISTOPHER MILLS 1Participant @christophermills1]

Neville,

Many thanks; the overall vote is for sling ties. Phil was demonstrating positioning with the rope. I can see how important it is to have the lathe held very tightly on the initial lift.

The more I looked at chains the more I found it hard to imagine protecting the lathe from them.

Chris.

[neville rigg 2Participant @nevillerigg2]

Chris, the trouble with chains is there is no warning before they go, I would never use them on any machinery, O.K. for steelwork and pipework.

Neville.

[CHRISTOPHER MILLS 1Participant @christophermills1]

Second revisit to the CovMac:

4th Headstock bolt is now free, and the head is loose, ready for removal – I have secured it on two headstock bolts, because left loose it will topple off backwards, being very back heavy.

Plinth is de-concreted, but tailstock end is harder: Beneath a concrete fillet lies a series of loose bricks – the tailstock end is higher, and the lathe's feet are about 2 inches off the floor of the shed.

The lathe will have to be jacked at that end before completing it. I did not want it to drop two inches by overdoing it.

Motor and mounting is very inaccessible, still, because the lathe is so pushed up against the wall – that will be tackled when I have the headstock removed, hopefully some time next week.

I have removed all loose stuff, four spare chucks, and half a ton of cutting tools and assorted goodies, and a lapping plate. 

In the meantime here is a picture of the CovMac's clutch in more detail:

What is in the clutch mechanism? What can I expect to see?

Under the top cover there are five vee grooves on the pulley wheel. The clutch is really quite big. I have disconnected the two vee drive belts from the motor.

The lathe was reconditioned by the same firm which did Phil's; I.L. Berridge of Leicester. Mine was renovated by them in January 1955, using the same reference number as the War Ministry allocated the machine. There were comprehensive Machine Tool Orders in the Second World War, regulating use and ownership of machine tools. 

Chris.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Edited By CHRISTOPHER MILLS 1 on 06/10/2014 14:33:11

Edited By CHRISTOPHER MILLS 1 on 06/10/2014 14:34:14

Edited By CHRISTOPHER MILLS 1 on 06/10/2014 14:35:00

[Phil WhitleyParticipant @philwhitley94135]

Hi Chris, It is only since you started this project that I have looked at the clutch mechanism, it appears to push two pins into a series of holes spread around the V belt pulley. Whilst that is what I can see I think there must be a bit more too it than that, I will look tomorrow. Referring to your picture if you remove the pivot bolt from the clutch arm , and loosen the nuts with the sc4rew slots in the bolts, the clutch arm comes off. I will check the exact details tomorrow. I removed mine because it sticks out quite a lot and I didnt want to break it. It may be a malleable casting, it may not, just not worth the risk. Good progress and good news that the headstock is loose, well done that man!

Phil

[Brian WoodParticipant @brianwood45127]

Hello Phil and Chris,

I'll await your findings with interest. I've been correspoding with Chris by email lately, some of it abour beekeeping, but he was puzzled by the slotted head screws in the periphery of the drum that you can see in his photo. I wondered if they secured an inner liner of some sort, possibly even in asbestos as in brake shoes, but fashioned into a cone; into which a steel mating cone is pushed to engage drive.

Then the visible grease bothered me so it may instead be a metal to metal cone, more in line with the sort of thing my shaper and Myford lathe have..

I am not much taken with the idea of pins being pushed into holes, hardly a smooth take up and very likely to shear off in use. So I share your suspicions that there are wonders to be revealed. This old lathe seems to be full of surprises; if you ever decide to strip off the screwcutting gearbox for any reason I have a list of questions on the internal details for resolution.

I imagine the clutch thrust collar bears down on a carbon thrust pad as in early vehicle clutches, today ball thrust bearings do that duty.. We shall see what you find

Regards Brian

Edited By Brian Wood on 07/10/2014 16:49:51

[Phil WhitleyParticipant @philwhitley94135]

Hi All, Brian, we were right! the clutch s far cleverer than pins or dogs. From what I can see, or rather more what I can feel when I operate it, there is some sort of spring loaded over-centre mechanism which pulls a plate over inside the drum. I an guesing at plate really, it could be a cone, whichever the take up is smooth and very positive, with no perceptable slip that I can create by hand. I all looks very straightforward to strip, as long as the contersunk screws come out of the drum! Mine also has a liberal coating of grease or oily gunk, but the lathe was working fine so i could be some sort of metal (bronze?) friction mateial. I have included two pics below (I hope). I have stopped trying to get the text and pics in order, it seems to make up its own mind where it is gong to put them, apparently regardless of the cursor postion. Pics show clutch in and out.

Phil.

[Phil WhitleyParticipant @philwhitley94135]

Or rather top pic is out and bottom one is iin (driving)

Phil

[Neil WyattModerator @neilwyatt]

> Chris, the trouble with chains is there is no warning before they go, I would never use them on any machinery, O.K. for steelwork and pipework.

I once heard of someone deliberately disabling an old hand crane … by cutting through one side of a chain link.

Well meaning but incredibly stupid.

Neil

[Phil WhitleyParticipant @philwhitley94135]

I understand your point about chains, but unless you are using a rust old lump of chain you found in a field, you are pretty safe! You should never lift with anything except the chain, rope or strop designed for that purpose, and it should of course be in good condition. Chains are very strong, and it is doubtfull you would snap a proper lifting chain unless you were attempting a lift like a traction engine. I have two hook chains sets from a blackhawk eurodozer car straigtening jig, the links are about 5/16 diameter steel and the hook is specially shaped to hook onto the chain to form a loop. One of them would lift the entire complete covmac with ease as they are rated at 20 tons! Like wise you hear horror stories about wire rope, but the golden rule is simply to use equipment that is in good condition and rated at well above the weight you are lifting, and if you see the filler twine coming out from between the stands of wire, RUN!

Phil.

[Brian WoodParticipant @brianwood45127]

I have witnessed a Yorkshire Dales farmer using a very tired wire rope to drag out tree stumps using the rear hitch on a big 4WD tractor with 100 HP on the wheels. Tired barely describes this rope, it had broken strands all down it and was maybe down the core when I saw this. Needless to say I gave it a very wide berth indeed; the lamentable lack of imagination shown was really beyond belief.

As Phil says, all that sort of tackle is OK when in good condition and in the example above he got away with it, but would that be the case another day?

When the same man was pulling full grown sycamore trees for me to control the line of felling, I made damned sure it was my rope and chains that were used. Huddled down with a chain saw at the base the last thing I needed was for it to lurch back on me.

Brian

[CHRISTOPHER MILLS 1Participant @christophermills1]

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

[Ady1Participant @ady1]

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

[Neil WyattModerator @neilwyatt]

Or cheap 'everyday' cola.

Neil

[Phil WhitleyParticipant @philwhitley94135]

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

Phil

[CHRISTOPHER MILLS 1Participant @christophermills1]

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.

[EugeneParticipant @eugene]

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

[MM57Participant @mm57]

More expensive, but very good

deox-c

…see "how to use" tab

[CHRISTOPHER MILLS 1Participant @christophermills1]

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

[Michael GilliganParticipant @michaelgilligan61133]

Well done, Chris !!

MichaelG.

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

[MuzzerParticipant @muzzer]

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

[Nick HughesParticipant @nickhughes97026]

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.

[Neil WyattModerator @neilwyatt]

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

[CHRISTOPHER MILLS 1Participant @christophermills1]

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 –

[Phil WhitleyParticipant @philwhitley94135]

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.

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