Instructables

Downsizing a broken Emco Compact 5 PC lathe to manual operation.

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I bought a Emco Compact 5 CNC lathe about 18 months ago. it had been in a school or something and had been thoroughly vandalized by the little sh... i mean ill mannered children and had been used by the guy i got it from just as a manual lathe.  There is a stepper motor missing the optical sensor was toast and before i got to use it something in the PC part at the back  died and the thing just would not go at all.

The lathe came with a quick change tool post and 5 tool holder which at the time where valued at little under the price of the whole outfit.

The lathe had  came from a school and had not been treated well, it was auctioned off and had some of the CNC parts removed and manual handles added, the guy I bought it from had been using it as a manual lathe.  With to much missing and the cost of repair back to full CNC being well out of the question as I just don't have the budget to do so, I decided that i would remove all the dead weight which would also reduce the size of the lathe for my limited work space.

I recently took the lathe to a friend  Brian Redmond (an ex Shorts engineer)who has a much better knowledge of all things electrical to get him to see if he could figure things out,   I was stumped when i found that the motor had 4 wires rather than the normal 3.  this kind of stumped the both of us as it didn't seem to be a 3 phase motor or stepper motor or anything that we had seen before.  So i left the lathe with Brian to see what he could come up with and if al else failed we could always replace the motor.

Brian lucky enough had a book called Electric Motors in the Home Workshop by Brian Cox which after a bit of researching through was able to tell that this was a capacitor run motor, most motor have a capacitor to kick start the motor and then a centrifugal switch turns it off,  this one needs the capacitor connected all the time run and that this was an uncommon type of motor but mainly used in small lathes.  With this info he was able to get the motor connected up with lest cables so it ran.  so it was now just a case of making a switch box that could also house the capacitor and wiring it all up.

I decided to add a NVR(no voltage release) switch as to lighten the lathe considerably so I can move it around if needed and make it a bit safer as i dont like reaching over the lathe bed to use the switch.  I got this from eBay for £8 including delivery.

I managed to get an PSU enclosure box that would hold both the capacitor and the switch in Maplin for about £6

With the PC removed from the back of the lathe it is considerably lighter I can just about lift it with out throwing my back out.

The NVR switch and capacitor where mounted in the enclosure box and 2 nice quality cable grommets where salvaged from the PC part and reused on the enclosure.

I don't have a wiring diagram as I left the wiring to Brian while I sat there like a stunned monkey occasionally  hearing words that my mind recalls from memories of boring physics teachers droning on about Ohms, and farads and resistance and such, as i sat there with a blank expression with my brain not knowing where to put such information, it basically went in one ear rattled around a bit and just left, so i will not even attempt to explain.

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It works but has a little issue I will not mention now until we solve the riddle and resolve the issue at which point i will get Brian to do a circuit diagram for wiring this type of motor.
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With the wiring complete the box was secured to the body of the lathe and I at last had a functioning lathe.

The Lathe is basic as is but it functions, with a few more mods and improvements it will be enough for the things i want to do. I need to track down a set of reverse jaws to suit the chuck and a compound slide.   

Since i have got the lathe running i have been researching the Compact 5 and trying to source spare parts, I am finding that functioning machines are making £1000+ on eBay and that most of these machines have been broken for parts, the lathe beds seem to make good money as they make base for custom built lathes. 

Here's a quick vid of the lathe being tested, thee was a parting tool in the post so i just used it to part off a pice of 6mm aluminium bar.  I still need to setup more cutting tools in the tool holders.


Thanks for looking.
rimar20001 year ago
Good recycling work, Dr.Qui. It is really a pity that a good and relatively expensive tool as this, has been vandalized.
Dr Qui (author)  rimar20001 year ago
Thanks, its a very old model, I recon round about 20 years old. there was something similar at the training college I went to which just sat around unused as there was no one that knew how to use it, it was so old it used micro tape cassettes to store the programs, that would be a dinosaur compared to today machines

I had put the word out to a few of my engineering friends that I was looking for a lathe and this one came up. The guy I bought the lathe from paid £250 for the quick change tool post and tool holders, and he asked for £260 for the lot and even threw in some cutting tools with it.

I found a picture of a more modern version of the Emco compact 5 its even bulkier ad the asking price was about £1000
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You have done a good trade!
Dr Qui (author)  rimar20001 year ago
(removed by author or community request)
Dr Qui (author)  Dr Qui1 year ago
Very lucky i guess, I found a picture of what my lathe would have looked like new, between 1981-92, the yellow one above sold for £1111.11 on eBay and turns out the yellow ones are older than the grey ones, that is crazy money for a machine that is close to 30 years old.
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pfred2 Dr Qui1 year ago
Little machines cost big dollars because they are what amateurs can see themselves handling. I call it the grandpa on the cellar stairs effect.
Dr Qui (author)  pfred21 year ago
We all don't live in huge empty houses with a garage the size of a hardware store with room for a South bend, Bridgeport, Colchester or the like.  

I know that my lathe ain't much but I got it for the price of the quick change tool post from an engineer who hit bad health and was starting to pass his tool collection on to anyone who could make use of them and he asked only for what he spent on the tool post.  Its got a long list of problems that i call now call the grievance list that makes me long for the Colchester that I had almost served my time on as a fitter until I had a RTA that left me with injuries that made engineering a career path I could no longer go down.  I left the engineering world at age 20 and crossed into other career paths so i never started a tool collection of my own, I never started building a tool collection until my late 30's most of the stuff I have may be old, used and don't bear the big name brands, but they do have history and stories attached to them and that's worth more than a big shinny snapon tool chest packed with the latest bit of garage bling that never gets used

I don't need anything bigger or more expensive, its used mainly for turning small decorative finishing touches for wood turning projects and some small hobby stuff, if i need the use of larger machines my engineering connections allow me to get machine time on bigger an better machines if needed.

So in summary i'm not an armature, I don't want or need anything bigger as its right on the limit of what I can safely lift without causing aggravation to old injuries. as i now have  limited income a new or bigger lathe was not an option and I made the best of a bargain form an engineer with a kind heart who wanted to see it be passed on rather than inevitably being auctioned off, since i post this Ible I purchased some more basic tools and the grievance list grows shorter, little machines don't always cost big bucks and there is no point in buying a 2 tonne machine to turn small hobby projects.  

I have a 2 tonne flat belt drill press that my Grandfather built his business up around some 80+ years ago that now stands idle and has not been used in maybe the last 5 years the reason being that i never need to drill a 3" hole in anything, the little bench drill press is more than enough for 95% of any drilling I need and local machine shops sort me out for any holes I need to drill in the 16mm to 25mm range.  We had a huge lathe that came from one of the old Belfast ship yards it had about a 20 foot bed and i can remember seeing it being used maybe 5-6 times when i was a kid, eventually got passed on to a guy who had and still has regular work for it.

Your grandpa on the cellar stairs metaphore is lost on me, very few cellars in this country we prefer to work above ground in sheds with windows and see the light of day upon our skin
pfred2 Dr Qui1 year ago
I left my comment in response to, "that is crazy money for a machine that is close to 30 years old". In no way did I allude to you being an amateur, but the fact remains that amateurs are the ones driving the prices up on small machines. You could pass from this Earth tomorrow and that wouldn't change the economics of the situation at all. Small machines would still command prices far in excess of their value simply because of the convenience they offer.

Now as far as my, "grandpa on the cellar stairs metaphor" goes it is to illustrate that amateurs often need to move the machinery into sometimes less than easily accessible locations in order to work with them. Grandpa ain't making it down the stairs with no lathe with any 20 foot long bed either!

In an ideal used market a small machine will always sell for more than many larger, and more capable counterparts would. It all comes down to paying for convenience. Lots of people are willing to do that, as is evidenced by your own findings. So your not always comment are exceptions, rather than rules.