Studer RHU 450 from the 1960s

[Richard King]

Take a look at this by my friend and student Stefan G in Germany. I was upset when I first saw it as he almost teaches word for word what I taught him. But I was wrong to be mad as I insist in the classes my students teach what I teach them. He did that to millions, not just a few youngsters at work...lol. He shows square cutting in the show. A good example on the bar he starts showing in the very first. diagonal lines of individual scrape marks.

I teach there are 5 Rules of Scraping (used to be the first 3, then 4, now 5)
When scraping for PPI and ways are with-in .001", not when roughing, I say then you scrape like your scraping paint off metal. long strokes and overlapping.

1. Scrape individual scape marks at diagonal lines across your part at 45 deg's to the edge.
2. Scrape individual scrape marks in individual lines separated from the first line or number 1. The gap should be approximately the same as the gap in # 1.
3. Scrape for depth of scrape marks need to be a minimum of .0002" to .001" deep.
4. Hinge the part or swivel the straight-edge or on a granite table so the it hinges or pivots at 30% from the ends. This is called Rotation of points or your checking the Airy points.
5. Clean with your hand before rubbing as you can not feel the dirt with a shop cloth.

Both of my You Tube students show these rules in their shows.
Scraping basics - Scraping flat - Part 1 - YouTube

Also my friend and student Jan in Norway. He has several shows on scraping.
16x2 inch cast iron plate scraping - YouTube

 

[ballen]

Hi Richard,

I'm grateful for your help, and have watched the videos at the links that you sent me.

I started this thread by asking for advice about the tailstock. But I'd like to put that aside for the moment to focus on the table and bedways.

I don't want to undertake a complete scrape down, because I don't have the time and skill. But I do want to create oil pockets to prevent the moving parts from wringing together and galling.

First question: should I do what Tyrone suggested, namely "break up the shiny areas with a scraper"? These shiny areas are mainly on the bottom V bedways. (I ask this because at least some of what I have read says that the pockets are often on the top surface and the bottom bedway surface is ground smooth and flat.)

Second question: you wrote, "at the minimum square cut the ways and give it new oil pockets and as I said a minimum of .0002" deep". What does "square cut the ways" mean? Does this mean that I should follow the pattern of the existing scrape marks running perpendicular to the direction of motion, and deepen these to 0.0002" or a bit more?

The videos you linked are about scraping a surface flat, and don't cover oil pockets. But I did find this 2-minute video from Nick Mueller which show creating half-moon pockets with a long scraper over his left shoulder, hitting it with his right hand. I could try this on a test piece and post the results here.

The (unmastered) art of flaking (decorative scraping) - YouTube

Starting about 12 seconds in, I think this next video shows "half moon" scraping with a Biax to create oil pockets. Is this what I want to accomplish (by hand) on the shiny part of the bedways?

Scraping and Flaking - YouTube

I think it would be hard to do this with a machine because the oil grooves would get in the way. But I want to confirm that my goal is to do this to the shiny parts on the V of the bedway.

Happy New Year!

Cheers,
Bruce

 

[Kees]

I don't want to undertake a complete scrape down, because I don't have the time and skill. But I do want to create oil pockets to prevent the moving parts from wring together and galling.

Then I would use some foil with the correct thickness to bring the main stock at the right hight. Simple, quick and rather precise. Most important: you hurt and spoil nothing and can always go back to the point the machine is now.

Important is how you use the machine: When grinding most people relaese the bolds and push the tailstock to the right. No matter how hard you clean there will be always grinding particals underneed the tailstock causing waer. The only way to prevent this is after grinding taking the complete tailstock right off the table (not moving) and cleaning it. Then you can put it back on the table for the next job.

Happy new year!

 

[ballen]

Hi Kees,

Then I would use some foil with the correct thickness to bring the main stock at the right hight.

We are no longer discussing the tailstock and work head. We are talking about the main flat and V ways for the left-to-right motion. But your point is well taken.

Happy New Year!!

Cheers,
Bruce

 

[Kees]

Oops, sorry!

 

[Richard King]

Yes Square Cutting means to break up the surface as Tyrone suggests it is a 1/"8 x 1/8" square oil pocket done with a hand scraper. The factory did them with a pull scraper it looks like. side by side with an un scraped area between each pocket.

I thought we talked about scraping when you rebuilt your surface grinder? 1/2 moon Flaking can be done and requires some skill a bit more the pushing a hand scraper and making same size oil pockets approx .0002" deep. If your a rookie it is hard to perfect the short scrape marf or pocket and you might just make 1/2" long ones side by side in lines or think of them as solders all standing in formation. Their heads are the unscraped areas and between them is the oil pocket. A uniform look. Other wise if your not skilled breaking them up would be like a crowd of people standing in a group spread apart in a random location.

When you 1/2 moon the spot is .002" deep. If I were you and don't have the experience of 1/2 moon flaking then square both top and bottom ways. I would not bother with filling the galls and just consider them deep oil pockets if your shill level isn't there.

95% of the time I never 1/2 moon the bottom side of any machine as I feel the .002" oil pocket and feel te grit can lay in there and gall up. Same goes for Milling machines but some like Bridgeport do it for the looks plus oil pockets. They say the way wiper cleans them out, but I disagree. Back to your grinder. I hate to self promote but I sell a DVD and BIAX Germany has copies of it. I was thinking I have students now in Germany who kknow how to hand 1/2moon flake and I have everyone's emails address. Just got back from teaching 30 men to scrape and 1/2 moon. Someone may live near you and I'm sure would gladly show you how? If not you can look at You Tube. Here are a few more showing scraping:
at 5 minute mark he shows bump scraping and once you figure it out it is easy to get short and square scrape - flake marks.
What is Metal Scraping? - YouTube

Richard King Scraping Class - YouTube

Richard King Scraping Class Day 3-5 - YouTube can skip o min 15 and he shows power 1/2 mooning. expensive machine so mastering hand flaking is a lot cheaper.

So many on there now showing it. Rich

 

[ballen]

Hi Richard,

Square Cutting means to break up the surface as Tyrone suggests it is a 1/"8 x 1/8" square oil pocket done with a hand scraper. The factory did them with a pull scraper it looks like. side by side with an un scraped area between each pocket.

OK, got it.

I thought we talked about scraping when you rebuilt your surface grinder?

It turned out that the geometry of the machine was within a couple of microns (around 0.0001") and the ways were pristine. The only problem was that there was 30 years of rust under the magnetic vise. So first I needed to learn to grind the vise flat, and eventually I got good enough to also grind the table underneath. It turned out well. But I need to take a class from you to learn the basics of scraping.

In the next days I'll break out my scraping stuff and start practicing on some cast iron scrap to see if I can make a checkerboard of squares that matches the pattern on the unlapped parts of the ways and has the right depth.

I would not bother with filling the galls and just consider them deep oil pockets if your shill level isn't there.

Does one deepen the galled areas with a dremel tool and then fill them with a 2-component material? That doesn't sound hard, but I will follow your advice and leave these alone for now.

Just got back from teaching 30 men to scrape and 1/2 moon. Someone may live near you and I'm sure would gladly show you how?

I wrote to you privately about that.

The second video you linked above, starting around 7 minutes and 9 seconds in, shows a student bump scraping. I'll try that technique on some scrap and get back to you.

Cheers,
Bruce

 

[Tyrone Shoelaces]

I didn't do a great deal on the smaller machines to be honest. Most of my way repair experience is with the larger machines. I used an angle grinder with a brand new hard pad to open up the smaller scores. I used it side on obviously. That gave you a square cornered groove. Some times I'd drill a series of small shallow holes along the groove to give the " Moglice " more of a key.

We also had a portable milling machine for large repairs. No use to you though, it was about 10 feet long !

Regarding the scraping I wasn't the perfectionist that Rich is. I'd get out my trusty BIAX flaker that currently lives in Norway and I'd lightly go over all the shiny areas in two directions. Then stone the lot down with my fine emery brick.

Regards Tyrone.

 

[Peter from Holland]

Bruce
To repair galling you could buy some SKC
The German moglice
See their website http://www.skc-technik.de/en/

Peter

 

[ballen]

Hi Peter!

To repair galling you could buy some SKC.

I actually have 60 or 70 grams of SKC-60 and a spray can of mold release in my shop. A year or two ago I used it to mold a replacement nut for a friend, who needed a nut with a 4-start thread with a 16mm pitch for a garage door opener. (This is a nut with four distinct threads, each offset by 90 degrees, each with a 16mm pitch.) It worked beautifully.

But from what Tyrone has written, to repair the galling first I would need to deepen/undercut the damaged areas to give the SKC a place to "key in" to.

Anyway, I have exchanged a couple of emails with Herr Schmidt at SKC, so to inform myself better I have written to him (auf Deutsch!) and asked if they have an Infoblatt about such repairs which they can send me.

Cheers,
Bruce

 

[Tyrone Shoelaces]

I used to work with a turner who would machine 4 start screws and nuts during his lunch break just for something to do.

Regards Tyrone.

 

[ballen]

I used to work with a turner who would machine 4 start screws and nuts during his lunch break just for something to do.

I would have done it on my lathe, but my lathe does not go up to 16mm/revolution lead!

 

[Peter from Holland]

SKC 63R reperaturbelag would be my choice
A lot of if not most information is on their website
http://www.skc-technik.de/content/wp-content/uploads/2015/07/antifriction_coatings.pdf

Peter

 

[ballen]

Peter,

the link is interesting, thanks. Page 17 explains the procedure. One has to remove material from the damaged area to a depth of about 1mm. Then clean the area, fill it with SKC 63R, and clamp a ground bar (covered in mold release) over it. I think that one must also remove the "squeeze out" with solvent before the material hardens, but this is not described.

For the first step, to remove material from the damaged area, it would be very useful to have a tiny 3-axis mill (Dremel/Proxxon) that mounted with a strong magnetic base. One could clamp it to the ways and easily "dig out" the damaged areas. Do you have such a tool or have you seen one?

Cheers,
Bruce

 

[dian]

did you say 68 way oil? isnt that a bit too thick?

 

[Peter from Holland]

Peter,

the link is interesting, thanks. Page 17 explains the procedure. One has to remove material from the damaged area to a depth of about 1mm. Then clean the area, fill it with SKC 63R, and clamp a ground bar (covered in mold release) over it. I think that one must also remove the "squeeze out" with solvent before the material hardens, but this is not described.

For the first step, to remove material from the damaged area, it would be very useful to have a tiny 3-axis mill (Dremel/Proxxon) that mounted with a strong magnetic base. One could clamp it to the ways and easily "dig out" the damaged areas. Do you have such a tool or have you seen one?

Cheers,
Bruce

The scoring I had was a bit bigger so I used a angle grinder with a 1.2mm cut off disk at a angle
In your case I would use a dremel with a cutt off disc
Go in on both sides of the scratsch at a angle Then remove some material in the middle if need be
All done manualy
Just drip in some SKC Do not overfill All that has to be removed Stirr it with a needle once applied to get rid of air inclusions You get those very easy
Then tape it off with some adhesive tape or put some tape on the masking bar
I prefere transparent tape as I can detect any air gaps at the surface then
Pouring it with a small long spurt helps to release any trapped air

After hardening I removed the exces material by scraping
And I then scrapped the whole guideway
Peter

 

[ballen]

did you say 68 way oil? isnt that a bit too thick?

The Studer RHU 450 manual calls for Mobil Vactra 2, which is ISO 68 viscosity. FWIW, this is thicker than the oil used in my J&S 540 surface grinder, which is ISO 32 viscosity.

 

[Richard King]

If you insist on filling the galling then I would recommend aluminum color epoxy. Over here we have Devcon plastic filler devcon putty | eBay
because when it dries it looks more like cast iron then plastic steel color is black. I believe the wear characteristics would be about the same. I agree on making the bottom of the hole / groove deeper and wider to lock in the material. Also drill a hole at the end on the gall or groove. I have also tapped the holes and used a small punch to push the epoxy into the holes. It will help keep the dirt out. Have to be sure to clean and re-clean the grooves. Also use a hand propane or Meps torch to boil out the oil that is in the iron. be careful not to heat it to hot.

Use white cloth to wipe away the oil residue that boils out. Then after it cools squirt with non oil electrical or brake cleaner aerosol. Then after it dries be careful not to scrape it to hard as it will be softer then the surrounding iron. Also I have talked to one of the Hamm Scraping Class students who will show ballen how to hand scrape the pockets. Hopefully they can hook up. Rich

 

[ballen]

Hi Richard,

If you insist on filling the galling

For now I am following your advice, so I will leave these alone. But I might return to this in the future, because removing the table and top takes half an hour.

Also I have talked to one of the Hamm Scraping Class students who will show ballen how to hand scrape the pockets. Hopefully they can hook up.

Thanks, I hope he will email me. I've ordered a 25x100x300mm (1" x 4" x 12") piece of GG25 (lamellar cast iron) to practice on. Eventually I can turn it into some measuring device bases.

Cheers,
Bruce

 

[Tyrone Shoelaces]

If you insist on filling the galling then I would recommend aluminum color epoxy. Over here we have Devcon plastic filler devcon putty | eBay
because when it dries it looks more like cast iron then plastic steel color is black. I believe the wear characteristics would be about the same. I agree on making the bottom of the hole / groove deeper and wider to lock in the material. Also drill a hole at the end on the gall or groove. I have also tapped the holes and used a small punch to push the epoxy into the holes. It will help keep the dirt out. Have to be sure to clean and re-clean the grooves. Also use a hand propane or Meps torch to boil out the oil that is in the iron. be careful not to heat it to hot.

Use white cloth to wipe away the oil residue that boils out. Then after it cools squirt with non oil electrical or brake cleaner aerosol. Then after it dries be careful not to scrape it to hard as it will be softer then the surrounding iron. Also I have talked to one of the Hamm Scraping Class students who will show ballen how to hand scrape the pockets. Hopefully they can hook up. Rich

What are your reservations regarding filling in the galling Rich ? Just asking as one pro to another.

Regards Tyrone.