Prvomajska TES 2 205 (1956) Lathe, Spindle Bearings and Ways, with pics

Just wanted to save her from being scrapped and to satisfy my addiction of having machinery at home. What do You think what Spindle bearings does she have (from pictured down below). She is supposed to have plain bearings but not yet sure.

Also in the video there is some clutch problem evident. Anyone with experience of reconditioning such a clutch?

Thanks, in next posts more pictures.

https://www.youtube.com/watch?v=dV8xYCqOQh0

There she is at home in the garage with headstock open, and also some minor problems mended.

Even more pics in next post...

Thanks.

Here shown the oiling system for spindle bearings. The crown nuts are stationary, they do not rotate with the spindle.

Thanks.

Hope You enjoy the pictures.

Thanks for posting the pictures, that lathe may or may not have plain bearings but what difference would it make. It looks to be very well made and if used and maintained as intended it will probably last a life time of use in a shop working 24 - 7. If you are trying to add more RPM's to it or something like that it might make a bid difference.
Dan

Not really trying to replace bearings cause they have zero play, just perfect. For higher RPM I bought another 2be restored lathe , a KERN in the pic below. However I need to know such details about my lathe if I own it I would think. On the other hand, she was not maintained properly and has some play(well, huge play) in the cross-slide and her clutch is another story.

Clutch, I might pull it out and install 1to1 shaft while the clutch is being refurbished. It´s a three phase motor on it and forward-reverse will do the "1-0-2" 3ph switch for the time being. If refurbishment fails that might be a permanent solution. Clutch will be documented and pics uploaded here.

Ways (cross slide ones), any idea on regrinding/rescraping those, suggestions? Pics of those soon here.

Camelback went as a present, KERN restoration will be a new thread, with lots of pictures and vids of course

Thanks, n.

Curious setup, the front bearing seems to be a weird bronze bearing while the rear bearing is a huge roller bearing. Any thoughts on that, why would someone design it like that?



Thanks,

n

Hello, just a quick update. Removed a chuck, it is a threaded type, unusual for a lathe of such capacity. There is a break or rather a latch to fix the spindle for a procedure of removing the chuck. The front bearing is a two piece bronze bearing with a steel sleeve pressed onto the spindle, something I did not expect. I never checked any run-outs. I expect this bronze bearing to have minimum run out, far better then with roller ones. Will get back with pics.

See You later and thanks,
n

That's gotta be the stoutest headstock casting I've ever seen, Every gearset is celled off like so many ammo bunkers.

Looks to me as though your spindle bearings are tapered and split and the two crown nuts shift them on the taper to adjust clerarance. That's a very good design, expensive to execute but results in superb product cylindricity. That machine if properly adjusted should turn roundness samples in the single digit millionths.

If you wish to open the clearance, adjust the nuts that way, etc. How you adjust them for higher RPM may be a trial and error process. My suggestion is mark the present setting so you can return to it, Open the clearance by too much at first and run the machne at max RPM for 20 minutes. Note the bearing temp with an accurare theromoeter. Reduce the clearance a bit and try again noting temps as you go. Repeat, shooting for 20 degrees STABLE tenperature rise or some such figure. Change oil to a heavier grade and the max RPM bearing temps may go up. Watch it.

What you are trying to avoid is thermal runaway where the bearings over-heat a trifle, the spindle and bearing shell expands a bit reducing clearance and heat progresses etc - until the spindle and bearing shell expand and heat to seizure. The final stages take seconds. Very bad scenario and you WILL err on the side of too much clearance.

Clutch problem and no spares? Not a problem with a three phase motor. Start across the line or add a VFD with the VFD being the preferred (and more expensive) option.

I don't know about your second lathe. I hope I dont insult you by suggesting it may be a harbinger. Be aware: people can get obsessive/compulsive about collecting old but worthy machine tools as others obsess/compulse about crockery, cars, or cats. I had a girlfriend in high school who over the years collected neglected horses until she had 30 or more. They overflowed her stabling and pasturage and her ability to buy feed for them. The county stepped in. I had to listen to her talk out her troubles on the phone for a couple mionths while the wranglling went on. It wound up with all but 3 horses being adopted out. Several horses were so old and decrepit they had to be put down. Very sad.

Whether you call people drunks or alcoholics depends on whether they are poor or rich. A car collector whose property is overwhelmed by rusting cars is one kind of collector, Jay Leno is another.

I'm just saying: collecting is insidious. I love machine tools. I would be a collector myself if I had the resources. There were dozens over the years that sorely tempted me but did NOT bring home. I still regret passing up a 48" American lathe with 20 ft of bed I could have had for free. I even had use of the company truck to haul it. Good machine in great shape, face plate drive, three steadys, long taper attachment, spare set of faceplate jaws, tons (literaly) of OK and Armstrong tooling but....

Older machines built in 50' have biggest center-height/spindle-length ratio. One of the important factors along with bed depth, bed width, spindle bore and weight compared to a center height.



I, definitely, will stop buying new machinery, started plans on building new shop/house so all funds will go that direction. However will start new thread on restoration of that interesting Fritz KERN lathe, look at the bed width:



https://www.youtube.com/watch?v=wVwvYUGye20

At the moment she is not in my but in one other shop so I have access to her like once a month or so(so far).

However, does anyone here have a clue on what licence was Yugoslav lathe built, any resemblance to any western or Russian lathes?

Anyways, thank You,

n

The clutch is a "Twin Disc" design and many times when they don't engage as yours had is caused because they are adjusted to tight. Now that you have it apart you will be able figure it out. On the western type you pull a pin and adjust the nut one pin hole or notch at a time and test engaging and disengaging it until the disc's don't turn. I Googled the lathe name and I see their still is a company in Yugoslovia that says it sells parts and services them. Thanks for all the great pic's. Rich

Richard King said:

The clutch is a "Twin Disc" design and many times when they don't engage as yours had is caused because they are adjusted to tight. Now that you have it apart you will be able figure it out. On the western type you pull a pin and adjust the nut one pin hole or notch at a time and test engaging and disengaging it until the disc's don't turn. I Googled the lathe name and I see their still is a company in Yugoslovia that says it sells parts and services them. Thanks for all the great pic's. Rich

Click to expand...

I think the clutch is broken, sometimes it can't disengage. Well I figured it can't disengage when one of those sliding pins rotates to bottom position. When the clutch is engaged the I can rotate it till the problematic pin is in down position and then disengage the clutch. All pins seem to be spring loaded except for the one that is freely "flapping". Other direction can't be engaged at all.

I can't invest 8hr/day time for the lathe at this time so I am doing it only sporadically.

Sorry, no more Yugoslavia, today that part is Croatia and Prvomajska as a company seems to be privatized. I gave them a call and their secretary answered. Weirdly she didn't want to put me through to some salesman so I left some data on the lathe and that I wanted the clutch repaired and some other stuff. A day or so later the answer was a rude "we can't help you". Just that no other info, no possibility to speak to someone of trade, nothing. Such a shame for once such a great company. Besides I don't think they are building any machinery for decades now, only like retail of Chinese POS(point of sale no, not really) or something else, I don't really know.

Anyways, slowly but surely I am inspecting the lathe part by part and will post here with pictures, I know everyone understand and loves pictures of nice machinery.

Thank You all for help,

n

From the video at yt it seems that they(Prvomajska) did build some machines in more recent years then I thought.

https://www.youtube.com/watch?v=qsd_u-gGH9g

Although in small batches it seems. Some of the machinery in the video have insanely deep bed castings, no cheap on budget machines there. Would love to know if they are still deploying some resources to build new machinery.


Thanks,

n

The brewery comradship images (all good buddies and co-workers and the shop cat in this together) aside they seem to do first class wprk on what look like components for CNC machines. Maybe they make and fit the sliding elements for assembly elsewhare.

asdf said:

Older machines built in 50' have biggest center-height/spindle-length ratio. One of the important factors along with bed depth, bed width, spindle bore and weight compared to a center height.

View attachment 138078

I, definitely, will stop buying new machinery, started plans on building new shop/house so all funds will go that direction. However will start new thread on restoration of that interesting Fritz KERN lathe, look at the bed width:

https://www.youtube.com/watch?v=wVwvYUGye20

At the moment she is not in my but in one other shop so I have access to her like once a month or so(so far).

However, does anyone here have a clue on what licence was Yugoslav lathe built, any resemblance to any western or Russian lathes?

Anyways, thank You,

n

Click to expand...

A few years back I worked on some Polish centre lathes that had certain similarities to that lathe. Who copied who I don't know.

Regards Tyrone.

Tyrone Shoelaces said:

A few years back I worked on some Polish centre lathes that had certain similarities to that lathe. Who copied who I don't know.

Regards Tyrone.

Click to expand...

Similar to which one? The one is a Prvomajska, a Yugoslav brand, the other is a german Fritz KERN(the one with protective cover over a missing chuck).

Thanks,

n

Today got around to take care of that broken handle at the gearbox. Lead screw and power feed are easily disconnected. Tapered pins hold the lead screw, power feed bar has four flute splines. Engaging lever has a pinion gear to engage the clutch, another shaft with receiving gear runs through the bed to back of the lathe where it is connected to the clutch lever.

Removed all the bolts and she dropped. Discovered it is a compactly enclosed unit weighing about 150kg ~300lbs.

Spared no expanse when designing the unit. Receiving shaft gear assembly has to go out to unscrew the flange as it bolts to the main housing and the cover, the same goes to the lead screw flange. In both cases only top two screw have to go out. Cover screws are not same for front and the back part of the cover. See pics.

It's easy to remember how everything goes back togather


Tadaaa...


Oil is older then I am most probably, all the gears and bearings are fine, she has some minor cracks, someone was in there at some point.

Welded the handle back together with a 95% cast iron rods, inverter, rod to negative setup. The handle was welded before, if I had the tools I would have gone for brazing. Now I can not remember why I didn't take some pics with everything assembled but with cover still off. I thought I did, but there is no pics of that in the camera.