Add oil channels to rotary table on my Studer RHU-450 universal cylindrical grinder?

[ballen]

A few years ago I got a Studer RHU-450 universal cylindrical grinder, and with help from Richard and others I scraped new oil pockets and fixed the geometry. The machine works very well, especially since I outfitted it with a DRO and built an ID grinding attachment for it.

There is another modification that I am contemplating, and I wanted to ask if there is any reason not to do it, or to get advice from anyone who has done this themselves or seen it before. This concerns the rotary table on the machine, show in the two photos below. The upper table is rotated on the lower one to eliminate a taper or to create a taper.




You can see from these photos that the sliding surfaces are surrounded by drainage areas, designed to carry away the coolant.

Now the issue I have is that I don't rotate this table on a regular basis. So when I do want to rotate it, I have to break it free. My question: would it make sense for me to add six ball oilers to the upper table, so that if I do want to rotate the table, I can inject some way oil into each of the bearing pads, from the top? If I do that, presumably I should cut grooves to distribute the oil.

(Richard, if you see this, I hope you are recovering from the surgery, and have the energy to respond. Our thoughts are with you.)

Cheers,
Bruce

 

[Bakafish]

I suspect the oilers and grooves will not work the way you hope (it won't break it free), and will just create reservoirs for swarf and corrosive fluids. I'd consider making some threaded holes in the top plate that can be used with some brass tipped jack screws that bear on non-contact surfaces of the bottom plate.

 

[ballen]

I suspect the oilers and grooves will not work the way you hope (it won't break it free), and will just create reservoirs for swarf and corrosive fluids. I'd consider making some threaded holes in the top plate that can be used with some brass tipped jack screws that bear on non-contact surfaces of the bottom plate.

I'm hoping to hear from someone with direct experience. If the oiler grooves never pass to a region that is exposed by rotation, then if oil is pumped in under pressure it has no option except to separate the two parts. Similarly, there is no place for swarf to enter. (Actually the issue on a grinder is not swarf but coolant and sometimes grit from wheel dressing.) Back to the theme of collecting swarf and fluids, I was taught (by RK) that to avoid this, the grooves should always be on the upper surface, which is how I propose to do it here.

Has anyone here seen such oil grooves on the rotary table of a cylindrical grinder?

 

[Richard King]

Thanks Bruce.. the surgery went well but I now have to learn how to move my arm as cutting the muscles and my arm in a sling for 2 weeks before the surgery and after the surgery the shoulder, elbow, wrist and fingers tightened up. i have 1 hour of therapy 2 times a week plus doing exercises 3 times a day is painful as hell. also fluid buildup swells my arm and fingers. one pain now is i have to type with one finger on my right hand, so a lot of lower case letters. i can't now make fist or move my left hand much. . hopefully by August i'll be power scraping again..

As far as your "swivel table" (not rotating) in all the different brand machines ive rebuilt i have never seen where factories installed oil supplies or grooves under there. With the harsh environment of coolant and grinding grit that could penetrate under there and possibly rust it or grit could scratch it. , i would squirt way oil on it when you assemble it. Like the old saying goes ''if it ain't broke don't fix it'', How old is your machine? in all those years, the surfaces look ok.

 

[Tyrone Shoelaces]

I’ve had several cylindrical grinders with that type of universal table apart and I’ve never seen any means of lubrication installed. However going from memory the pads were usually bigger than those in the photo.

That doesn’t mean to say it’s not a good idea.

Regards Tyrone.

 

[???]

My Ribon grinder has exactly the same setup and no grooves. The angled surface for coolant runoff does seem to be a lot steeper on the Ribon, may just be the photo. I did what Richard suggested, lube with way oil when I lift it for cleaning. The fine adjustment screw on the table also exerts a huge amount of force which should be more than enough to break it free .

 

[ballen]

Hi Rich,

Thanks Bruce.. the surgery went well but I now have to learn how to move my arm as cutting the muscles and my arm in a sling for 2 weeks before the surgery and after the surgery the shoulder, elbow, wrist and fingers tightened up.

I'm glad that the surgery is behind you. Even though it hurts, try and keep moving those muscles, because it's the only way to keep the range of motion. Check with your PT, but I think typing is a very good way to exercise them, because in order to keep your finger or fingers on the keys, you have to use everything from the shoulder and back down to the arm and wrist and fingers.

As far as your "swivel table" (not rotating)

Thanks for correcting me. I'll call it a swivel table from now on, I didn't know the right expression.

in all the different brand machines ive rebuilt i have never seen where factories installed oil supplies or grooves under there. With the harsh environment of coolant and grinding grit that could penetrate under there and possibly rust it or grit could scratch it. , i would squirt way oil on it when you assemble it. Like the old saying goes ''if it ain't broke don't fix it'', How old is your machine? in all those years, the surfaces look ok.

I have not been able to date the machine, but I am pretty sure that it is from the last 1950s or early 1960s. However those surfaces are not original. I know that because when I was checking and correcting the geometry, I found that the bottom of the swivel table was flat within a few microns over four of the pad areas, but the pad to the far left was 130 microns (about 0.0033") too low. So someone had ground it in the past and f**cked it up. There is absolutely no way that the machine would have left the Studer factory like that.

I got a local grinding company with a 2-meter travel machine to regrind the underside of the swivel table -- they got it flat to a few microns.

Anyhow, what you have written has made me less enthusiastic about doing this... but I'm still contemplating it. If my oil groove goes back and forth along the center of the pad, swiveling the table won't expose it, so I don't see how grit and coolant could get in there.

Cheers,
Bruce

 

[Peter from Holland]

got a local grinding company with a 2-meter travel machine to regrind the underside of the swivel table -- they got it flat to a few microns.

Flat to a few 0.001mm??? Is that what you mean by microns ???
Who was that ???
To a few 0.01mm yes perhaps But a few 0.001mm over that lenght ??Thats a whole other ballgame
Peter

 

[michiganbuck]

Huge overkill and expensive would be to make all travels including the spindle an air bearing system. I never like the grit lines on a table swing but don't know any way to avoid them.
We brought an old Cincinnati Tc grinder in from another shop and looking under the swing table found a brand-new surface, guess it ran only one job for its early life.

 

[stephen thomas]

Whenever i have to swivel the top on my Cincy #2 i clean up whatever mess is under it, liberally coat with LPS#2, and then put it back.
Like someone else said, the fine adjustment screw will move it will little effort most of the time. Times it feels tight, i disengage it and loosen the table bolts a bit more, stick a bar in the end of the T-slot and use that for a little more leverage.

Mine has never actuall "stuck", though.

If as stated your intention is to hydraulically lift the table when necessary, you could still add the oil ports, just don't add any grooves under the table. I don't think it will take any more or less time and effort to "re-settle" the table when it is reset.

smt

 

[MCritchley]

The ground on ground surface might be a bit sticky, you may have a wringing phenomenon going on. Break it up with a few scraping passes.

 

[ballen]

Flat to a few 0.001mm??? Is that what you mean by microns ???
Who was that ???
To a few 0.01mm yes perhaps But a few 0.001mm over that lenght ??Thats a whole other ballgame
Peter

The company is HOPPESCHLIFF GmbH + Co. KG, Mogelkenstraße 26, 30165 Hannover.

Machine knives for trade and industry - HOPPESCHLIFF

Your partner for machine knives: experts in circular knives and straight knives. We are masters of our trade. For four generations.

www.hoppeschliff.com

They charged me 370 Euro, including VAT. They promised to get it flat to within 10 microns (0.01mm, see attached) but it turned out better.

The swivel table is about 1 meter long, and needed no fixturing. They used their best grinder, dressed the chuck, then put the table upside down on the chuck. I don't think they shimmed it because the swivel table top was already very flat, but I can't remember. Then they took a number of passes. The magnet was turned off - the table was just resting under its own weight. I also remember that the had a very specific grinding wheel (50 or 75 mm wide) that they got out of the back room to use for this, it was very coarse and open.

After they finished I checked it on my surface table, which is 800 x 1200 mm. My table has an 11 micron dip in the middle, but is quite flat around the outside. The grinding work was done well - I would go back to the company again if I had similar work.

Cheers,
Bruce




PS: I think it's interesting that this business' main work seems to be grinding industrial knives. I know this this is also the core business of one of the regular contributors here (Cash, from Kinetic)

PPS: here are the geometry tests after I finished my repairs:

 

[Tyrone Shoelaces]

The company is HOPPESCHLIFF GmbH + Co. KG, Mogelkenstraße 26, 30165 Hannover.

Machine knives for trade and industry - HOPPESCHLIFF

Your partner for machine knives: experts in circular knives and straight knives. We are masters of our trade. For four generations.

www.hoppeschliff.com

They charged me 370 Euro, including VAT. They promised to get it flat to within 10 microns (0.01mm, see attached) but it turned out better.

The swivel table is about 1 meter long, and needed no fixturing. They used their best grinder, dressed the chuck, then put the table upside down on the chuck. I don't think they shimmed it because the swivel table top was already very flat, but I can't remember. Then they took a number of passes. The magnet was turned off - the table was just resting under its own weight. I also remember that the had a very specific grinding wheel (50 or 75 mm wide) that they got out of the back room to use for this, it was very coarse and open.

After they finished I checked it on my surface table, which is 800 x 1200 mm. My table has an 11 micron dip in the middle, but is quite flat around the outside. The grinding work was done well - I would go back to the company again if I had similar work.

Cheers,
Bruce

View attachment 400729


PS: I think it's interesting that this business' main work seems to be grinding industrial knives. I know this this is also the core business of one of the regular contributors here (Cash, from Kinetic)

PPS: here are the geometry tests after I finished my repairs:

Excellent results on the tests. Err, only one n at the beginning of renovation. Mrs Shoelaces is an English teacher so I’ve been well trained.

Regards Tyrone.

 

[Richard King]

If you decide to scrape in some oil pockets - measure the swivel table at the extreme angle setting and only scrape the areas that are not exposed to the air. I don't think you have an issue. If that was an issue the factories would have done something on all the machine i have rebuilt. one of my last jobs when i was scraping full time was a CNC Studer Grinder at Minnesota Grinding and that newer machine did not have anything other then what all the older machines had.

If the plate was ground then will you have to re-scrape the head and tail-stocks? The heights have changed.

 

[ballen]

If you decide to scrape in some oil pockets - measure the swivel table at the extreme angle setting and only scrape the areas that are not exposed to the air.

Yes, of course.

If the plate was ground then will you have to re-scrape the head and tail-stocks? The heights have changed.

Yes, yes and yes.
First, I did the headstock, then I did the tailstock, then I did the spindlestock, to get the spindle centerline at the same height as the headstock and tailstock centerline. (As you know, that's important so that tapers are conical sections rather than hyperbolic sections.)

In principle, if everything had been correct before grinding the swivel table, the only thing that would have to be lowered is the spindlestock. But it turned out that the headstock was not square in the vertical axis and that the tailstock was the wrong offset from the front table and also the wrong height and also tilted left to right. So in the end I had to scrape all of them into alignment. I did the headstock first because it was heavy and cumbersome. It was right at the limits of what I could carry back and forth to the surface plate. Scraping it took a lot less time than remounting it to see how far it was off in the tilt. Then I did the tailstock that was a lot easier to carry back and forth to the plate. Again, most of the time was measuring it and not the actual scraping. Eventually I got some rules of thumb for how many scraping passes were needed to remove a certain amount of tilt and that sped it up. Finally I did the spindlestock, looking back at the photos I think I might have just ground it, not sure if I had to scrape it.

Here's a few random photos from that, some years ago

Headstock:



Tailstock (notice the test bar stuck in the quill)



Spindlestock:

(after I lowered it, I also needed to modify the clamping mechanism, that was based on eccentric cams that were now at the wrong height)



update, no I must have scraped that too, because I found this rub after grinding. I had to do it in two passes because my grinder is 450 x 150, so needed to blend the different parts. The photo reminds me that I also relieved the center part and restamped the machine number (587) there.



PS: Rich, I see that you're typing capital letters... I hope that means that your fingers are getting better. Typing is a great way to get those muscles moving again.

 

[Richard King]

Yes, I can use my left hand to shift . I was able to scratch my nose with my left hand...lol...yayyyy. I am glad you remembered to lower the middle. Your scraping looks good too. One thing I discovered that I need to drink 6 to 8 glasses of water or my blood pressure gets to low and I get dizzy. I also bought some Electrolyte powder to make my own Gatoraid.

Bruce I want to compliment your wok. It's a real threat following your work. You are teaching the members. Keep up the Great work! Oh do you have a copy of Testing Machine Tools? If not email me and I'll send you a PDF of it.
Rich

 

[ballen]

Yes, I can use my left hand to shift . I was able to scratch my nose with my left hand...lol...yayyyy. I am glad you remembered to lower the middle. Your scraping looks good too. One thing I discovered that I need to drink 6 to 8 glasses of water or my blood pressure gets to low and I get dizzy. I also bought some Electrolyte powder to make my own Gatoraid.

Rich, at first I felt a bit guilty about dragging you out of convalescence to get advice. But I feel better about it now. The best thing you can do for yourself is get as active as you can, enough that you stop thinking about how miserable you feel, and move around. That'll help get your muscles working properly again and ideally tire you out enough that by the end of the day you collapse into bed and sleep well.

Bruce I want to compliment your wok. It's a real treat following your work. You are teaching the members. Keep up the Great work! Oh do you have a copy of Testing Machine Tools? If not email me and I'll send you a PDF of it.
Rich

I'm grinning from ear to ear. Seriously, I have some bragging rights now. Thank you!

One of the things that I love about fixing precision machinery (and I think that is true of everyone reading this) is that it rewards us for our compulsion in getting it right. Metal is unforgiving when you get it wrong (try putting a 10mm pin into a 9.995mm hole) but when you get it right it stays that way.

And thank you, yes, I have a copies of Dr. Georg Schlesinger's book both in English and in German (:-). I was looking at it when I was scraping in my Studer, figures 84 - 96 show the different tests that are needed. The people at Studer also sent me a copy of their test protocol sheet, so I "did it right".

By the way, if you don't know anything about Schlesinger's life, it makes for interesting reading. He was born in 1874, and when he was in his late 20s and 30s helped to set up many of the institutions and publications which formed the foundations of best engineering practice. He also invented and patented the first stainless steel, what is known in German as V2A or in the US as "304 stainless".

During the first world war 1914-18 he was already middle-aged and took over the leadership of some important factories that made weapons and munitions. But when Hitler came to power in 1933, Schlesinger was arrested because he was jewish, kept in jail for "investigations" for seven months, and then forced into early retirement with no pension. Eventually in the late 1930s (Schlesinger was more than 60 years old at the time!) his german citizenship was revoked and he first moved to Switzerland and then to London.

Cheers,
Bruce