The journey continues…
We’ve taken apart the apron and most components of the lathe, but the motor still remains and some other aspects have to be addressed… Grab a cup of “something” and start reading!
Removing the motor
The motor on my lathe is a single phase capacitor start AC motor, it’s 1420RPM 3/4HP.
C1 is 100uF (starting cap), C2 is 12uF (running cap)
4.5A nominal current, model number is YL8014.
They sure rate it as 3/4HP, but it’s more like 1/2HP in reality.
Removing it is the hardest part I’ve encountered so far, because of how difficult to reach the lower mounts are.
If you want to remove it because it’s not working, make absolutely sure it’s not a simple capacitor fault. If you want to remove it for weight reasons or reassembly / inspection — keep reading!
To begin with you might want to remove both belts so the motor will be free to move away once the mounting nuts are released.
The motor is held by four nuts, the mounts are screwed onto the cast iron bed. Each nut has a lock washer and a washer, this is what makes it difficult to undo them at first, and due to how hard to reach the lower ones are (specially the lower one by the headstock) it might require some special tools or a dose of ingenuity.
At this point you have to ask yourself if you can lift the entire lathe up to get more clearance underneath the motor, or if you have the actual tools to reach without trouble.
To access the upper two nuts, you might want to remove the electrical box that sits on top of the motor, it’s held in place by three screws and you can read about how to remove it on the electrical portion of this lengthy guide.
The four nuts are 10mm, a combined wrench will do just fine for 2-3 of them, but like I said that last one is hell unless you lift the lathe up, if you do lift it make sure you lift both sides equally — you don’t want to stress the bed in any way.
Also, if you try to tilt the entire lathe to the side to gain more clearance by the motor, make sure you aren’t forcing the gearbox handle onto the table / box (wherever your lathe is) because you will snap it or bend it and that’ll be the end of it. If you plan to tilt the lathe, put the gearbox on the “1″ position and lock it, if you removed the gearbox faceplate, use masking tape or string to keep the lever up by the 1st position (first gear to the left), otherwise try some wooden shims.
Once the four nuts, lock washers and washers are out, and assuming you took the belts off, the motor should slide right out. Before I did this however I made sure to undo the cable nut that goes from the motor to the electrical box, this way I was able to turn the box and gain a bit more clearance, plus we also avoid stressing the cable in any way by releasing tension.
To slide the motor off, I decided to support it on some scrap wood so I didn’t have to force myself with all it’s weight at once (and to prevent possible dissasters, plus I should not stress my wrists too much, so that’s another reason for this step).
And that’s all there is to the motor, in my case the fan protector (which is held by three small phillips screws) was all bent up and had been touched up with paint (it probably had rust and they covered it up). It was almost touching the fan, so I was forced to remove it and straighten it up. Of course, I also wet sanded and repainted it with black gloss, high temperature paint. (I would’ve use matte, but anything that will most likely catch oil and swarf should be slick as to not attract more crap).
The motor typically sits underneath the electrical box, and on top of it lies the swarf shield / cover, so not much dust or swarf goes on it, however some of it always finds it’s way into the motor fan.
It goes without saying that you should grease up the gears. Some people use motoroil instead and they pour it through the oiling ports, it works but it gets messy real fast. Either way, keep them lubricated and if you are not to use power-feed or threading operations, don’t leave the gearbox engaged.
When the gearbox is not engaged, the gears on the handle are still moving, they’re coupled to the drive-train, but by disengaging the gearbox you remove wear from the leadscrew mounts (there are no bushings or bearings, it just rolls on a cushion of oil against the polished cast iron)
Better models have a spindle gearbox, these often have a sump for the oil and are more complex, but the leadscrew is mounted and driven in almost the same way.
The wiring is almost top notch, which is surprising but here’s the problem, the run and start capacitors for the AC motor are complete trash. So I highly recommend you replace them even before you decide to start turning metal. I of course turned for a few minutes during the inspection to make sure everything worked, but with the lathe as-is you should not use it due to lack of lubrication and proper setup.
Now, why replace the capacitors? because they won’t last very long at all and they will scare the crap out of you when they do fail short, they will also ruin your day if they fail open or fall so far off spec the motor just stalls and won’t even turn. Let me remind you, the motor costs a lot more than the two capacitors, so invest in a couple good caps and get it over with!
To remove the capacitors you’ll either need special low profile tools to reach the tiny 7mm nuts that hold the capacitor shields or, you’ll have to take the electrical box out (it’s held by three allen head screws, one of which is underneath in between the capacitors, so you’ll have to remove the right cap first to get to the allen).
Both capacitors are installed with twist-on wire nuts, which is fine.
The other lacking point on the wiring is the mains cord, it’s not even a 3×2.5mm which is the absolute minimum I would’ve used for these loads (specially the starting load, to prevent drop and thus excessive current draw) — So you may want to replace the power cord with a proper 3×2.5mm or 3x3mm.
Earth wise, no locking washer was placed on the allen screw and the paint was not cleaned off, so the only contact made was through the screw and not directly onto the body, which isn’t good. The torque on that screw was also very low, earth connections should be solid for safety reasons. So, address that as well once you reinstall the box.
The reverse switch is very small and flimsy, nothing like what you’d find on older lathes… But for now it’ll do, it’s actually a good quality unit as is the safety switch, but due to personal preferences you may want to replace these for something that makes you feel safer, for now I’ll keep them.
As stated, remove the shipping oil from all mating surfaces. Two safe chemicals are acetone and brake cleaner, I chose the former. The idea is to strip the shipping oil off and keep cleaning until no residues are left on the rag. Even at this stage, if you were to oil and reassemble, you’ll soon notice the oil becomes darkened after a few passes. This is due to friction of uneven surfaces “mating” together, but mostly due to residues still left in the metal that are being washed off by the machine oil. Steel and iron are porous metals, specially if cast. You can actually think of most metals as wood, for instance iron (ask any blacksmith) is fibrous and thus very similar to wood.
I use light machine oil for everything now. I don’t buy into the whole “you must use special way oil and special spindle oil and…” — Most people use motor oil, some even swear detergent or non detergent makes no difference when it comes to the ways of the lathe bed and other components. One issue with the viscosity of certain oils is how often you’ll have to lubricate the machine. Most of the gears are not under heavy load (unless you are knurling or performing heavy cutting operations with the power feed) but still I prefer to use lithium grease on the gears.
Speaking of viscosity, most “way oil” has additives in them such as a viscosity enhancer, the idea being it’ll stay in place for longer… problem is, it will also catch a lot of swarf and dust. I’d rather use light machine oil often and in excess, than use sticky oil that will ultimately make a mess and force me to spend time cleaning it up afterwards.
It’s all up to you, lubrication is like talking about religion or linux for that matter, everyone has a different opinion so it’s better if you experiment and come up with something that works for you and your lathe.
However I would like to add that some lathes have been around for over 100 years and they’ve always been oiled with regular motor oil (20w) So it all comes down to how well you take care of the lathe, not exactly which type or brand of oil you use. Because more often than not, you’ll fall into marketing traps and waste your money over nothing.
Lubrication on a lathe and any other equipment is akin to the lubrication on an internal combustion engine, it’s the life of the engine so don’t take it lightly either, make sure you absolutely cater to the requirements of your specific tool.
If you decide to use grease for the gears, try not to over-do it as it will not only sound like there’s a chewing monkey inside the lathe (or the lathe is chewing up a monkey?) but it will eventually make a sticky mess in there. You have to avoid oil and grease making contact with the belts to prevent slip under load (the friction causes heat and loss of material which in turn can easily shorten the life of the belt, specially if it’s under heavy tension).
No spindle tachometer was provided, but the electric box has a cutout right where the headstock is, and wouldn’t you know it, the headstock also has a cutout, so you could rather easily install a bracket with a hall effect switch and place a magnet on the outer portion of the spindle (2 gram magnet). Then use shielded wire and an insulated box for your own electronics. There’s plenty space in the original box, but you might want to run the low voltage portion on a separate box and just place a transformer or smps board inside the original box.
Another idea would be to add an SSR or figure out a way to interface with the original safety switch relay so that a micro-switch could be used on the bed to prevent the toolpost from running into the chuck. There would still be some momentum going after you turned the motor off, but at least it wouldn’t keep going until it either sheared a key, caused gear damage or worse. (chucks are not cheap!)
For a finer degree of speed control a VFD could be used, however the supplied motor has a centrifugal switch, so I’m not entirely sure how you’d interface a VFD to one of these. The other -not so cheap- alternative would be to replace the motor with a treadmill motor, which are ideal for this application, of course they require a separate driver but it should be worth it.
Right off the get go you can see the belts are lacking, severely. Specially the V belt… it’s way too thin and it will slip if not break easily. I’ve read some people assume they’ve used a thin belt to “reduce vibrations” but that’s most likely marketing bs. Whatthey’ve done is reduce costs even further, as the older versions had a 3 times thicker belt and pulley system in there.
However, we can’t just replace the belt with a thicker one, we need to replace the pulleys… you could get away with two new pulleys but the drive train has three of them, one of which is slotted for the distribution belt. So it would be quite a task to reproduce it without a mill or an indexing setup. If you had a spare one you could part off the V pulley portion and turn a new one, then interference-fit it with loctite for good measure, keyed would be even better. I say “if you had a spare one” because I’m not too keen on modifying one-off parts.
Lots of play on the apron longitudinal feed, the shaft is not supported on both ends and none of them are mounted on ball bearings whatsoever, most don’t even have a bushing. So that’s something to think about and be concerned specially if you plan to use your lathe on a daily basis.
The banjo is rock solid, by this I mean it’s very hard to actually use it when you’re to change the gear ratios, so that’s something to look into. I might end up adding a DC motor drive to the leadscrew and calibrating it for different feed rates based on the required threading pitch or finish, but we’ll see in the future!
Steadies require work as well, one of them had two of the fingers shoved in place with a hammer (you could not move them at all by hand let alone by the tiny adjusting screws) so I had to deal with it and I’ll probably write a separate article on them, as I plan to spring load the fingers and I will toy with the idea of adding bearings to the fingers (possibly new fingers). So far I failed to acquire the correct spring wire thickness, since it wasn’t available at the music store, but we’ll get there!
Conclusions for now…
After you’ve dealt with all the issues and added your own personal touch, it becomes a very capable small lathe. However, as it comes from the box, it’s not really a usable piece of equipment. So be prepared to invest some money and lots of time into rebuilding it.
Don’t be discouraged though. Some of us cannot acquire big old lathes not for free not for a mountain of cash, so this is all we can get. Some of us don’t even have the space for a big old lathe, so there’s nothing to think about right there. If you plan to invest on one of these chinese lathes, simply assume it’s a kit. Everyone I’ve spoken to agrees with this notion, but we were all fine with it due to the aforementioned reasons. You do get what you pay for, but it’s not complete trash if you understand what’s involved in it’s proper setup.
Even though I had removed everything but the headstock and the spindle pulley, the bed itself with the headstock and gearbox still weighs around 80KG easily, at first glace you don’t really appreciate how heavy cast iron parts can be, even when hollow. I’m still thinking “what did I get myself into!?” but the end result should be very rewarding, so I must keep on going!
Most of what has been said applies also to the full gearbox models sold throughout the world, as most of the parts are the same.
That’s all for now, hopefully it’ll be of use to someone. I know I’ll be reading this when and if I have to take it apart in a few months or years!