On 11 February 2026 at 13:02 JasonB Said:

As it is happening in one of the speeds where the motor is belted directly to the spindle it would be worth trying it with the second belt removed, it could simply be the unloaded aluminium internediate pully is vibrating as it turns.

If I understand you correctly that would make sense, but in that case it would also vibrate when the motor is not connected to the spindle, wouldn’t it? That’s not the case. To clarify, with motor pulley A, intermediate pulley B, and spindle pulley C, my status quo is:

• A is always belted to B. When running the motor just like that, no vibration.
• Belt from B to C (with A still connected to B), vibration.
• Belt from A to C (with A still connected to B), vibration.

Common denominator seems to be C here.

On 11 February 2026 at 15:21 Graham Meek Said:

One thing that occurred to me this morning while changing the belt position on my C5. There should be an M6 bolt directly beneath the motor position which rests on the bench, or swarf tray. This is adjusted to just take the weight of the motor assembly. Do not tighten this too much as it will disturb the lathe bed geometry.

Regards

Gray,

Good point. When I rebuilt it I realised exactly that: the previous owner had it too “tight” (in the sense of raising the tray too much), which made the tray below the motor (on the left) slightly lifted (even without the bold/foot) where as the right part is flush with the surface. Affects geometry for sure but I don’t know how much of an impact it would have on vibrations.

Talking about geometry: I also realised the holes for mounting the lathe to a bench are not perfectly aligned with the ones in the tray, especially the right one. This could be due to either the lathe/bed being twisted, or the tray. In both cases I think this was a poor design by Emco, as mounting the lathe and the tray to a bench forces you to add tension to the system if the holes don’t line up. A slotted hole in the tray would have been superior IMHO.

I have now replaced both belts. Additionally, I have significantly reduced belt tension. It’s not that it was overly tight before, but I now did keep very loose. These measures did indeed help reduce the vibrations; there is still a bit of vibration left, but I assume this is normal.

Spindle play: I can’t feel anything significant by hand, but I’ve ordered a dial indicator to check this more thoroughly.

One thing that remains and worries me: there is whirring noise at high RPMs. This could simply be expected, as I guess a spindle revolving at high speeds will always induce some sort of noise (just like a drill or angle grinder), but I am unsure it’s normal on a lather. Bear in in mind that this is my first lathe, so I have no experience or benchmark as to what is considered “normal”.

I shot a video with audio of the lathe running at maximum speed (2400 RPM):

https://youtube.com/shorts/AQtgYidfBPQ

I know it’s hard to tell from a video (especially the noise seems a little exaggerated on this one), but I’d be grateful to hear you guys’ thoughts.

I just wanted to follow up on this as I have replaced the spindle bearings, and this has entirely solved the issue I had with noise. As I didn’t find many resources about this particular topic online, I thought I’d quickly document it here in case it helps someone in the future.

Disclaimer: I am not a machinist, nor do I have experience with lathes or the Emco Compact 5. The following is all based on my personal knowledge and assumptions. I have good knowledge of mechanics in general and am an engineer, but again, have never done this particular operation before. English is not my mother tongue so pardon some of the approximate terms.

General Overview

• The bearings are press-fitted onto the spindle and into the housing.
• The play-free assembly is given by the spring-loaded washer (20) that adds tension along the axis of the spindle, and is held together solely by the circlip (17).
• To allow the spring loaded washer to function, the wheel-side bearing is less snug than the chuck-side bearing, allowing some (very minimal) sliding of the spindle along its axis.

Disassembling 

First remove the bed and engine.

1. Remove the circlip (17) from the spindle, being careful not to damage the teeth of the spindle.
2. Use an extractor to remove the wheel, being careful to nicely position the claws in order not to damage or bend the wheel. I used a washer positioned at the end of the spindle to position the main screw of the extractor (forgot to take a picture).
3. Now a very light tap with a mallet (from the wheel side) should set the spindle free (with the chuck side bearing stuck on it).
4. Remove the retention discs (21), then the inner circlips (22).
5. Now you can extract the bearing from the spindle using the same technique with the washer. This fit is much more snug, so be careful to align everything carefully in order not to damage or bend the spindle.
6. Optional: you can now remove the cast aluminium part holding the bearings from the housing by undoing four hex screws.

I used the opportunity to thoroughly clean everything.

Used a washer so that the extractor can press right against the middle axis of the spindle. 

Reassembling

You have to replace the cast aluminium part inside the housing. At this point I don’t recommend tightening the hex screws (for the housing) back immediately, as you might want to align holes (and the bottom part touching the bed) later on.

1. The trickiest part is to press the bearing back onto the spindle. I don’t have the proper equipment but generally wanted to avoid hammering, and tried to apply the pressure as evenly as possible, even though ideally it should be on the inner ring. To do that I cut myself out a rough wooden jig, then used my drill-press to slowly press the bearing down, rotating the whole assembly by a few degrees at every press to make sure everything is even.
2. Replace the inner circlips (22) and retention rings.
3. Feed back the spindle and bearing from the chuck side. You’ll have to give it some light taps in order to press-fit the bearing back. Make sure everything is properly aligned and not to damage the aluminium. You can temporarily place the bearing on the other side to ensure better alignment.
4. Place the spring loaded washer and bearing on the other side. In my case a few taps using my wood jig helped, I almost didn’t need a mallet.
5. Place the wheel on top. Here I found it easier to rotate the whole assembly so that I could press the wheel down with my hands against the table top. I chose to do this because I didn’t want to risk using a mallet or similar and bending the wheel.
6. As soon as you can see the groove, replace the circlip (17).

The bearing on the wheel side, sticking out slightly due to the spring-loaded washer.

My setup using a wooden jig and my drill press. Not the best, but better than hammering. 

Notes

• I used two extractors: one 110 mm and one 250 mm.
• I didn’t use any form of lubricant. I just ensure everything was very clean, and applied a very light coat of grease on the spindle to protect it from corrosion. Bearings stayed in the solution they came in. Other parts got a final WD40 and wipe just for cleanliness.
• About the method: I guess you could also place the chuck-side bearing in the aluminium housing first, then insert the spindle. I didn’t want to do that as the fit is very tight, so 1. I was worried to damage the aluminium and 2. I wanted to make sure the bearing was properly seated on the spindle, which is hard to see when it’s already mounted.
• The bearings set me back CHF 30 a pair here in Switzerland (I guess they are even cheaper in most countries). Got SKF made in Italy.

Bottom Line 

The old bearings where definitely worn off and the cause of that noise and some of the vibrations. The operation was actually easier than expected, and I am amazed that it’s possible to service even those on this machine. As it’s my first lathe, I couldn’t be happier I was able to do that as frankly speaking, I felt really stupid and sad once I brought it home and discovered it was making weird noises. As someone stated above, I thought it was it’s “death knell”.

I hope this helps, and I am happy to hear your thoughts, questions, feedbacks.

On 24 February 2026 at 07:20 Pete Said:

Overall my C5’s motor is quite smooth and quiet. More of a hum than anything else if it’s the only thing turning and the spindle and gearing isn’t. For whatever reason, I’ve read and mine does as well that the C5 motors usually run fairly warm after it’s been in use for some time compared to other single ph motors. I’m not saying it is, but your video almost made is sound like there could be a piece of swarf touching the motor cooling fan blades? My fan is plastic, but maybe at least worth a check?

Fwiw, many of the more entry people don’t know this and I didn’t as well when starting out. Anytime your setting up any of the change gearing, they are not meant to be pushed together and fastened in place. That would be a zero backlash position and creates excess friction and wear on the gear teeth. A quick easy and cheap method is to cut up a piece of standard printer paper into strips about 1/2″ / 12 mm wide. It usually measures around .003″/ .08 mm thick. Put that between the two gear teeth, squeeze them together, tighten the bolt or nut, rotate the gears a bit until the paper comes out. That positions and sets the gears with a bit of clearance and backlash. And in most cases they’ll run quieter as well.

Paper is made in numerous thicknesses, so you can use those to set almost any backlash clearance you want. Sometimes steel or cast iron gears will run there quietest at just one particular clearance. I can use cigarette rolling papers that are only .001″ / .025 mm thick. Even folded to get multiples of that number as well. Setting the gear clearance with a strip of paper is an old machinist trick that works just as well today.

I checked everything but the noise came from the bearings. I changed them and everything is running smooth, see above.

I am aware of the paper method, it’s actually what Emco describes in the manual 😊