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

Picture of 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.
rimar20002 years 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)  rimar20002 years 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!