CovMac Lathes

[CHRISTOPHER MILLS 1Participant @christophermills1]

Sorry, chaps – I have been in error – reading relevant gearbox information plate on the machine, I see top speed for a 13" geared head CovMac is actually 450 rpm, not 335.

Chris

[Phil WhitleyParticipant @philwhitley94135]

Gospel according to Tony, Chapter 6 verse 3 says the 445 rpm top speed is on the belt drive (conehead) model, but they may have been later mods as both ours are much later models than the one illustrated on tony's page. I will check mine today and see what it says on the plate.

Phil

[Brian WoodParticipant @brianwood45127]

Hello Phil,

​The 17 inch model at Leicester currently for sale on eBay has a top spindle speed of 450 rom, from a pulley speed of 320 rpm, that is the same as you will have

The data plate for the gearbox has been added in response to a request and it makes interesting comparison when compared to that fitted on your lathe and Chris's—–there are subtle differences throughout the speed range. The gearbox however will have identical internal gearing to deliver the outputs it does, despite the rearrangement of the external levers. It makes little sense to me to do that, why change? It costs money to change such things, there must have been a reason but it escapes me entirely.

​Brian

 

Edited By Brian Wood on 05/10/2016 09:31:29

[Phil WhitleyParticipant @philwhitley94135]

Hi Woody, needless to say, I forgot, been very busy putting the last sheets on the new roof, will look at mine tomorrow!

Phil

[Phil WhitleyParticipant @philwhitley94135]

At long last the Covmac leaves its dusty lair, and enters the main workshop, through a door that didnt even exist when it went in there! First job was a thorough clean, and tomorrow I will move it into its new home, and reassemble it. I have decided on a three phase motor, as the repulsion induction variable speed single phase one that came off it is so huge and heavy I doubt I would be able to hoist it up at an angle to refit it without turning the whole plot over and probably having an accident. BTW, it isn't two tone, the whiter brighter bits are in natural light from the door, whils the yellow bits are under fluorescent lights.

[CHRISTOPHER MILLS 1Participant @christophermills1]

Phil,

Fantastic to see it!!

You have beaten me wholesale

Best

Chris

[Phil WhitleyParticipant @philwhitley94135]

I only got it out of there yesterday, and cleaned it todayI will post a few more pics after tomorrows fun! The engine crane is only there in a supporting role, it will lift it (just) but it is mainly to prevent toppling, and to help with my nerves, it is a heavy brute.Good to hear from you again Cris!

Phil

[Brian WoodParticipant @brianwood45127]

Hello Phil,

Nice to see the old Covmac coming back into daylight again. Looking at the lathe again after this break in time it is still a very businesslike piece of machiinery and made to last, thank you for reminding us what it looks like.

And nice too to hear from Chris again, I thought you had disappeared into a trench in the marshes in Kent!

By the way, you may not remember but tomorrow is the first anniversary of our joint rescue of your old Hendey lathe from that farm workshop at Ellington near York

Best wishes to you both

Woody

[john fletcher 1Participant @johnfletcher1]

Hello Brian,Phil and Chris. Phil and Brian in particular being sort of local Have you ever thought of joining PEEMS at Pickering, a mens metal working club in its broadest sense. In November we have a talk on the Field Marshal tractor later we have CUP Alloys talking about Silver Soldering, later still, a talk on a home built aeroplane. We had a good visit to JCB factory and to ARC at Leicester. John

[Brian WoodParticipant @brianwood45127]

Hello John,

Some 35 years ago I had major surgery on my right eye , twice, to re-attach the retina, having had cataract surgery beforehand. Ever since then I have struggled with driving in poor light conditions with the damaged vision from that eye and eventually ceased night driving voluntarily.

Getting to and from Pickering from my home on the outskirts of Thirsk is fine in daylight, but not on for me in the darker months so for that and other reasons I have been a freelance operator and not affiliated to any club.

Thank you though for the invitation. I can't speak for Phil but Chris is London based so it is hardly practical for him

Kind regards

Brian

[john fletcher 1Participant @johnfletcher1]

OK Brian well that is understandable. I don't like driving at night either and so get a lift with a friend. to club meetings . I don't like those modern blueish head lights to much glare. Members come from far and wide, not every member turns up at every meeting, nor do I for that matter. John

[Phil WhitleyParticipant @philwhitley94135]

todays Covmac progress was mainly repainting the legs , plinth and chip tray, and seeing if I can remember how it all goes together. It is pretty obvious, apart from a bracket which has something to do with the belt guards, but I am sure its position will become apparent as I reassemble, which I am not going to do till it is in the new "machine shop", which may be tommorow, if the paint dries overninght, otherwise, Monday! The mystery bracket bracket is the one on the floor by the plinth in pic2. it is, needless to say, not original. Although the coolant pump is "a bit of a rig" I have decided to refit it, as I like the fact that it runs from the spindle drive, and so coolant stops when the chuck stops. Now heres a thing for Chris, is your chip tray cast or welded from sheet steel? they are cast on the lathes.co.uk pics, but mine looks like it may be a replacement, although it is an exact copy, and both yours and mine are later versions of the ones in those pics.

Yes, I know! Its white, and the lathe is a sort of faded magnolia, which was probably white once, and then got thoroughly oiled for about 60 years, if I can't live with it I will tone it down with some "White with a hint of wayoil" During the cleanup for the paint, it looks like the original colour was a dark grey, the same as the one Chris has , so it looks like it was repainted at IL Berridge, where it was reconditioned in 1955. Meanwhile, in the spirit of every TV presenter from Fanny Craddock to Blue peter, " here are some I prepared earlier" in their new less cramped habitat.

[Phil WhitleyParticipant @philwhitley94135]

Well, the paint was dry, so I cracked on and moved the lathe into position, and got most of it reassembled, including refitting the motor plate. Next job is to get a motor!

Edited By Phil Whitley on 22/06/2018 19:15:39

[Roger Williams 2Participant @rogerwilliams2]

Lovely to see tha Covmac on the ME site again !. Looks a treat.

[CHRISTOPHER MILLS 1Participant @christophermills1]

Phil,

What sort mechanism do you think there is within the big clutch drum?

Chris

[CHRISTOPHER MILLS 1Participant @christophermills1]

Phil,

I cannot recall my chip tray, whether cast iron or steel, but I will look next week, when I go to Somerset

Best

Chris

[Brian WoodParticipant @brianwood45127]

Phil,

Looking at Chris's photos I think he too has a sheet metal tray, the sections are not quite thick enough for a casting in my opinion..

Your new shop is shaping up nicely, you have put a great deal of work into that.

Best wishes Woody

[Phil WhitleyParticipant @philwhitley94135]

Cheers Woody, it has been a long haul on the workshop, but almost finished now, just have some rendering on the outside of the "blacksmiths shop" wall, a ceiling to plasterboeard and skim. then a bit of paint, and we are finished! The reason I have moved the covmac now is in order to get that part of the building empty so I could do the final work. Still to come out are forge (in bits, sl easy to move) Brazing hearth, a startrite bandsaw, and a Grafton drill press on stand, a workbench with three grinders on it, and all my metal stock! Thats next weeks job. I was reading about your eye problems, engineers must lead parralell lives!, I have had cataracts in both eyes removed, but only suffered one detachment in my right eye! I don't like night driving either, I dont think any glasses wearer does, as any slight lense scratching which is unnoticable during the day is a curse at night.

Chris, Clutch mechanism? short answer is, I dont know, as I havent stripped it, but from the feel of the way it works, it seems to snap into either the run or the stop positionI would guess at some sort of lightly sprung over centre mechanism which uses friction pads to take up the drive. It couls be along the lines of a brake drum where the shoes are released and forced against the wall of the drum to initiate drive. I dont think it is a dog clutch, as it seems totally smooth and silent in operation, but ATEOTD, I am just guessing! Did you get any change wheels with your lathe, as I have noticed that the brass plates on the banjo gear cover gives all the different change wheel and SC gearbox set ups for metric threads. Whwn I have a minute, I am going to make a list up and see if, for completeness if nothing else, I can match some up!

Phil

Edited By Phil Whitley on 23/06/2018 20:02:40

Edited By Phil Whitley on 23/06/2018 20:03:06

[Neil WyattModerator @neilwyatt]

That sure is a hefty machine, nice to see it coming along.

neil

[Phil WhitleyParticipant @philwhitley94135]

It is Neil, and very top heavy, which is why I put the crane on it. The crane is rated 750Kg, and will just lift the heavy end, but I used it as a safety to keep the lathe upright, and to ease the weight on the rollers. A big sigh of relief after it got there upright and in one piece though! I moved it by myself, as whenever I have had "help" in the past, I have spent more time stopping them getting a rupture or turning the thing over than I have actually moving the machine. Slow and steady wins the race. It took just over an hour to move it about 9 metres! You can move just about anything with a couple of good long prybars, and some 1" rollers, oh, and a smooth CLEAN floor helps too!!

[Ian S CParticipant @iansc]

A car jack and some bits of 4×2 can be a big help too, and don't rush things.

Ian S C

[CHRISTOPHER MILLS 1Participant @christophermills1]

Moving lathe weight is a real knack: My professional machinery mover, Edward Rutter, moved my CovMac bed, headstock plinth and tailstock plinth, 9 inches across a concrete floor, just using his hands and arms, nothing else at all

Chris

[Phil WhitleyParticipant @philwhitley94135]

Well, I have fitted the coolant pump, and decided I can't live with it, it really is a horrible bodge! In order to line up the pulleys the pump is spaced off from the plinth on two long "brackets" of bent flat bar, two of which are bolted into the plinth, and two are bolted to the motor mounting plate, which moves when the belts for the main drive are adjusted. Because of the cockamamey geometry of this rig, when the motor plate moves, the pump is twisted out of alignment with its driving pulley, on the left side of the input shaft in pic 2. I noted when I bought the lathe that there was no belt on the coolant pump, or coolant in the lathe, and it seems very reasonable to suspect that this rig up never worked reliably, if at all! Scrapping this set up also means I will no longer need the outboard belt guard, which increases the width of the lathe by about 18". I shall fit a small electric pump under the lathe, near the sump. I also did some bull work on the plates! the long plate on the changewheel cover gives all the gears required for cutting metric threads up to an unbelievable 10MM PITCH. If anyone has any gears 7/8" bore, 1/4" key 12dp (thanks woody!)I may be in the market, especially the elusive 127 tooth metric conversion wheel .

Note to Chris, re the clutch, I noticed the other day when I fitted the drive control bar, that when you put the lathe into run, a wedge lug on the operating mechanism forces two matching wedges apart, and mine appears a bit sticky, so I may be going in to clean up and lube. I will keep you posted.

Phil

[Phil WhitleyParticipant @philwhitley94135]

The new motor for the Covmac arrived, and I picked it up today, here it is next to the original motor. It weighs in at 32kg, and I lifted it out of the car boot with little trouble. A few days ago I went to move the old one, managed to slew the shaft end round a few inches, but couldnt move the other end at all! Good thing the new one is lighter, as the next job is to line it up for fixing hole drilling on the motor plate, which is vertical at the back of the lathe, but first, I need to bore the old pulley from 1-1/4" out to 38mm. It already has a steel bush in the centre, so easy job (famous last words!) The old motor is a 2hp, the new one is 3hp!

[Brian WoodParticipant @brianwood45127]

Hello Phil,

10 mm pitch metric thread—-I agree with you; unbelievable!! Actually, exaggerated claims for screwcutting performance on lathes is not confined to Covmac, particularly when the leadscrew pitch of 6 tpi is taken into account.

6 tpi is equivalent to 4.233…mm pitch and even threading at 1.5 times leadscrew pitch only gets to a little more than 60% of 10 mm pitch.

I made a 63 tooth wheel for Chris which will happily give a good range of metric pitches up to 4.5 mm all to within 0.001 mm error. The 127 tooth wheel is really not needed and the chances of finding one in 12 DP size is rather small I would think.

Best wishes Woody

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