A new lathe

[Sonic EscapeParticipant @sonicescape38234]

Yesterday I saw here in my city an Emco Emcomat 7 lathe in decent condition. I couldn’t make up my mind if to buy it or to order a new HBM180 lathe. But today, due to morning optimism, I bought it. The price was less than half of a new HBM.

I have also the cover on the left side and a lot of gears. The seller was very talkative. But the language barrier was significant. I think he said that he made some of the gears. Also they don’t look original. From what I read, one weak point of these lathes is the two levers for the headstock gearbox. But this ones look fine with no visible cracks. It has a three phase motor and it needs and external inverter. It has also the tailstock.

I did some measurements. But since I don’t have a reference or experience I can’t evaluate them. Maybe somebody could comment on this.

First I removed the chuck and I cleaned very well the Morse 3 taper in the headstock spindle. Then I inserted a calibrated MT3 test mandrel (+/-3μm if I remember well). I put the indicator on the carriage and run it across the length of the mandrel for ~220mm. I did this 4 times, rotating the spindle by 90° each time. I repeated everything once more and the results were similar:

The deviation is not linear relative to location of the indicator. This means there is wear on the bed.

Next I fixed another indicator on the carriage and I measured the runout on the internal taper.

The error is ~5μm. That is poor. My big 800kg lathe has <2μm here. If I pull up and down the spindle the indicator measure a 15μm deviation. This must be a cumulative error due to lack of rigidity of carriage, headstock and bearings. If I fix the dial indicator on the headstock and try to push again the spindle the deviation is decrease to ~4μm. This must be only the bearing play. Should I replace it? Or preload it more?

This is how it is looking inside the headstock:

There is a green thick oil inside. I got also a 5l metal can with the remaining oil. It was manufactured in 2001! I think I’ll change it. Is interesting that there are no metal gears meshed together. Some are made from textolite. To decrease the noise. That is nice.

Here are the gears. Not all are mounted. They look fine, no missing teeth or signs of wear.

The lead screw has some wear on ~10cm portion. But it is quite simple and the thread is 14 x 1.5mm, nothing special. I think I could make a new one if really needed.

Overall the lathe is nice. I like the large top saddle. You could fix many things there. I’m going to clean it and repaint it in more joyful colors. That brown looks hideous.

 

[bernard towersParticipant @bernardtowers37738]

I think you have a lot more to worry about than what colour it is!!

[peak4Participant @peak4]

If you head to this site, and scroll down, you should find some useful documentation
https://archive.org/download/lathe-manuals

Bill

[JasonBModerator @jasonb]

Quite a lot of Emco documents, files and knowledge on the Emco user group. I used to have the slightly larger Emcomat 8.6

https://groups.io/g/emcoV10lathe

Other places that can give problems are the buttons at the rear and also the metal casting on the front of the cross slide though I did not have issues with either.

Looks like you need a couple more gears in the train to be able to drive the leadscrew, if only for feed. Hopefully you should have those

 

[DiogenesParticipant @diogenes]

The mandrel test might not be reliable until the bearings are adjusted/overhauled – even then, the mandrel is long enough to ‘sag’ under it’s own weight and the pressure of the gauge – BUT this is probably good news, eh – if the (adjusted) carriage doesn’t get stuck before it reach the tailstock all is probably okay..😁

..overhaul & re-adjust, a cut test will reveal the truth in ‘real world’ dynamic conditions which can be far more useful than static metrology.

If the bearings sound & feel okay, check the adjustment first, I wouldn’t disturb them unless you really have to.

So check adjustment of everything, then cut metal and see how it turns out.

[Andy StopfordParticipant @andystopford50521]

Try this:

http://neme-s.org/Rollie’s_Dad’s_Method.pdf

You might find things aren’t as bad as they seem.

[Neil LickfoldParticipant @neillickfold44316]

Getting nice spindle bearings would be fairly high on the list for me. The bed wear can be re scrapped and does take time. Painting would be last on my list of things to do. The saddle could also have uneven wear also, so keep that in mind when reworking a machine. I use the tailstock end, to correct any saddle wear, then use the saddle as the guide to correct the machine as a whole. Be nice if there was somewhere close that could regrind the bed.

[peak4]

On peak4 Said:

If you head to this site, and scroll down, you should find some useful documentation
https://archive.org/download/lathe-manuals

Bill

Thank you for the link, I already had another version of the manual

On JasonB Said:

Quite a lot of Emco documents, files and knowledge on the Emco user group. I used to have the slightly larger Emcomat 8.6

https://groups.io/g/emcoV10lathe

Other places that can give problems are the buttons at the rear and also the metal casting on the front of the cross slide though I did not have issues with either.

Looks like you need a couple more gears in the train to be able to drive the leadscrew, if only for feed. Hopefully you should have those

 

The buttons are bypassed. The 3-phase motor must be connected to an inverter. No problem here, I have 3. I have the gear for feed, is the large one. I got also that pile of screw cutting gears. The seller keep telling me something about them but all I could understand was that they were ordered from somewhere. I didn’t paid much attention to them. But now I saw that they don’t have a keyway or a set screw. I’ll check this later.

On Diogenes Said:

The mandrel test might not be reliable until the bearings are adjusted/overhauled – even then, the mandrel is long enough to ‘sag’ under it’s own weight and the pressure of the gauge – BUT this is probably good news, eh – if the (adjusted) carriage doesn’t get stuck before it reach the tailstock all is probably okay..😁

..overhaul & re-adjust, a cut test will reveal the truth in ‘real world’ dynamic conditions which can be far more useful than static metrology.

If the bearings sound & feel okay, check the adjustment first, I wouldn’t disturb them unless you really have to.

So check adjustment of everything, then cut metal and see how it turns out.

The carriage is adjusted and I don’t feel any difference when I move it all the way to the right. Actually on my large lathe the carriage almost can’t reach the right most position. The bed wear is more severe. But even so I was able to make a 350x40mm mandrel with a diameter difference of less than 5μm across its length. I guess bed wear is not that important. But on the big lathe the bearings are perfect.

Right now I’m cleaning the lathe, there is swarf in many places, some parts are not well lubricated, there is dried grease and so on.

When you change the oil in a gearbox is a good idea to clean the old one? The current oil is ISO VG 220 gear oil. Very thick. I’m thinking to pour some 300ml of acetone in the gear box to flush the residues. Could be a problem with this?

[Sonic EscapeParticipant @sonicescape38234]

I discovered that there are a few workshops in the area that can rectify stuff. Most of them are rectifying engines, but some have also large surface grinders. I got a quotation of 194 euro for the bed of this lathe. This includes the top and the two sides of the bed. Is this a reasonable price? And how can I find out if a a workshop has an accurate machine? Is is common to stay with them while they are machining the bed? I don’t want to make two trips and I’m also curious about the process.

[Sonic EscapeParticipant @sonicescape38234]

I powered the motor alone to check how noisy it is. It turns out to be the noisiest motor I ever had so far!

So I made a trip to the bearing shop. In the second video you can’t notice how quiet it became since the phone is keeping a constant volume. But just consider that now you can hear the inverter’s PWM hiss that is quite faint and it was buried in noise with the old bearings.

Little work and huge improvement. I like this.

 

[Sonic EscapeParticipant @sonicescape38234]

Today I wanted to throw away the old oil from the gearbox. After that I poured about 0.3l of white spirit and cleaned everything with a brush. But some of the screws looked too appetizing. So I started unscrewing something, then something else, and finally it ended up here. I couldn’t help myself.

On this occasion I saw that a tooth is missing here. What effect does this have? Just a louder noise or will it also be noticeable as an uneven movement? Is there any point in replacing it? It’s not made of metal and I think I could make a new one. Since I’ve already taken everything apart.

 

I also painted the motor. It looks much better than that faded color. I found a blue paint with a very strong pigment. Just one application was enough. I didn’t use primer, I just wiped the engine very well with acetone. I put a white primer on the bed. But the yellow paint is not as good as the blue one. After two applications, traces are still visible.

I’m taking the frame to be rectified on Monday. I found a shop that claims to be able to ground it to a flatness deviation of less than 10μm!

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