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Schaublin 102TO restoration

Nozomi

Plastic
Joined
Feb 13, 2017
Hi all,

I recently bought a Schaublin 102TO from the 60's (bench model with reduction gear w25 spindle) which I
planned to restore and put in use in my hobby workshop.
Here I want to document the project and ask for opinions and technical knowledge.

This is my first post, so I will introduce myself first before going on topic.
I have been reading and learned allot from the PM forums, thanks all!
If you don’t like long posts, stop reading here!!! this is gonna be a long one ;)


I work as an electronics engineer and have been playing with electronics (designing and making pcb's,
programming, …) since forever. The last 5 years or so I started to like mechanical engineering more and
more and specially instrumentation, precision parts and mechatronics. I am always collecting tools and
machines which I use in my too small hobby workshop.

As for machines at the moment I have the following:
- Small shop tools, grinders, bench drill, horizontal band saw, …
- Chinese lathe (270 x 700 mm)
- Optimum BF20L converted to CNC with steppers and ballscrews (ongoing project)

Below a few pictures, planning to move into a bigger workshop soon.

q7clw9z.jpg


kgN80XQ.jpg



Recently I have allot of interest in watchmaking and am totally addicted to the work and books of George
Daniels. As it happend I found 2 nice lathes in a short period of time, a G.Boley 8mm watchmakers lathe,
but thats for another thread, and a Schaublin 102TO.


Now on topic: the Schaublin 102TO I'm restoring

This is my first quality machine tool and I am very impressed with the overall fit and finish and
tolerances. I did some initial measurements on the geometry and all seems to be very nice, I will check
geometry after reassembling the lathe and correct at that time if necessary. Apart from the paint and the
grease used for the bearing the lathe looks to be in good condition. I read up allot on the 102 before
buying one and feel comfortable restoring and adjusting this machine.

A few pictures as I received it with all the included accessories.

Q1sDUtg.jpg


vkS8BV7.jpg


JQjZP2l.jpg


T3Uq8ab.jpg



Disassembling the slides:

ZxrSk3I.jpg


VtcWX88.jpg


Disassembling the headstock:

bh2Y2in.jpg


CYHTJiJ.jpg


Notice the ISO32 oil recommended in the manual became very thick and black around the bearings,
or they used grease but i can't believe somebody would :eek::angry:

tnlGJzN.jpg



To continue with a question:

The front bearing is listed as a NN 3009K-SP (with conical ID ) which is easy to find (but expensive).
On the back of the spindle there are 2 AC bearings listed as 7208-C15. Im not too familiar with bearing
designations but I assume this refers to a 7208 bearing with 15deg contact angle.

As the 102 rear setup uses a ring between the inner races and locating ring on the outer races (pushing
them together) I think the tolerances for matching don't matter in this case. I'll have to machine the
locating ring to the exact preload anyway (2-5um axial clearance according to the manual).

90yAwh6.jpg


I see 7802 bearings ranging from $50 to +$400.
For example a SKF-7208-BEP is cheap, but this has 40deg contact angle?
It looks like the rear bearings mainly locate the spindle axial, so 40deg would be better than 15?
However if schaublin recommends 15deg, I'll go with that.

Will a SKF-7208-CD/P4ADGA be suitable?
Any recommendation to which bearing to use in this case?
Tolerances, ABEC class, ... ?




All input on the project appreciated!
Pictures will follow when I move along...


Kind regards,
Nozomi
 
What bearing did you take out? What does it say on the bearing?

That style headstock originally came with 6208 bearings.

I think you want ********* B7208-E-T-P4S-UL, which is 25°.

A cheaper alternative would be ********* 6208 TB P6.
 
Thanks jCandlish for the info.
I didn't know 6208 bearings were used in the 102. I googled around and see they changed from 6208 bearings to
7208 at some point before changing to the AC front/back setup on the 102N headstock. Also the 6208 pair was not
preloaded with a shim between the inner races as they do on the 7208 setup but just mounted face to face.

The bearings I pulled out were one SKF 7208B and one NTN 7208, so i don't want to use this as a reference.

You mention the ********* B7208-E-T-P4S-UL with 25deg CA, so i wrongly assumed that the C15 suffix in the cross
section drawing means 15deg. Probably the C15 is a tollerance/clearance spec then?

So basically I am looking for a 25deg bearing with P4 tolerances which would be the ********* B7208-E-T-P4S-(UL) or
SKF 7208 ACD/P4A.

Furthermore I was thinking if I use bearings for pairing with a light preload (suffix ********* UL or SKF GA) it
should be better to use a shim of the same thickness between the inner and outer races (or non at all) and
mount the bearing to their manufactured preload i.s.o. using the back cover to adjust the clearance.
Any thoughts on this?

@706jim: it looks like this once a year ;)
 
A pair of identical, if not matched bearings. Matched means they’re selected after being measured. Similar diameters and play or air in order to distribute the forces evenly. Measure the spindle first at the places where the (new) bearings will be.
 
Yes I understand about the matched bearings.
I mean if i get matching bearings I might as well mount them face to face (with equal shim between inner and
outer races) as where they are designed for opposed to the original setup where a ring between the inner races is used and the back cover pushes the outer rings together. I think the first will be easier to setup correct.

What do you mean with measure the spindle at places where the (new) bearings will be? Diameter?

Anyway I have contacted my bearing supplier for a quote on ********* B7208-E-T-P4S-UL or SKF 7208 ACDGA/P4A bearings.
I still have to check the front bearing if it needs replacement or just a good clean up.
 
After some PC trouble, here is a small update on what I did last weekend:

Found an accessory set in the local hardware store especially made for the schaublin 102 ;)

28Upwn6.jpg


Got prices in on the bearings (SKF NN 3009 K/TN/SP, SKF 7208 ACD/P4A and SKF 7208 ACDGA/P4A.
Way cheaper than i expected, so happy about that. The only odd thing is that 7208ACD is more
expensive than a 7208ACDGA, seems strange as the matching properties for GA are defined.

I further stripped down the headstock, tailstock and drive unit, making everything ready for sand blasting.
Made some covers out of HPL to protect the bearing bores and plugged/taped all non painted surfaces.
Decided to go for a epoxy primer / polyester filler (if needed) / polyurethane glossy top coat.
Found some nice products from Tikkurila which i can source locally:

Temacoat GPL-S primer
Temadur 90 PU top coat


XfoiUWC.jpg


uxY6HAq.jpg


LRvws4d.jpg




Disassembled the drive unit. I'm planning on restoring the dahlander motor (needs new bearings and paint) but got a new
1.5kW 240/400V 15000rpm motor because I want the flexibility to use it on single phase 240V with a VFD. Hope this can
save me the changing V-belt, so I can get full rpm range with changing only the flat belt from drive unit to spindle.
It's a cast iron base motor from WEG.

s9EDWax.jpg


IJ8liVa.jpg




Further cleaned and polished the nameplate and the viewing glass from the tailstock. Because the rivets or drivescrews
that hold the namplate to the bed are hardened steel, I had to grind a slot to remove them with a screw driver. Almost
all of the heads broke in half while unscrewing, guess i grinded a bit too deep, but managed to pull them out afterwards.

2VRu3CT.jpg


K2pB1cZ.jpg



Before cleaning the nameplate had a messing like color, after degreasing this appears silver in color.
And after lapping found out the base material is messing.

Does anyone know which color/ which plating was used on these type of nameplates originally?
I like how it looks now but I am thinking to re-plate it to original appearance.
 
Another question:
I read something about the original color being close to RAL 7012 or more accurate to NCS S B7005-80G (anglo-swiss-tools.co.uk)
and had it matched at the paint supplier to a RAL effect 810-5, which all seems quit close.

I am actually tempted to go for a white color i.s.o. the original.
There are some white rebuild 102's on offer at Luthy which I really like:

luthymac.ch


Is there any info about this?
Did they ever came out of the factory in this white color? Maybe only the 102N's.
What color of white is it? Looks like the original color the recent 102N's come in.

Any opinions? Keep the original color or go for a white coating?

Kind Regards
 
I believe the on newer white/blue machines the light grey is RAL 7035, and the dark blue is RAL 5013.

Pretty sure that Luthy machine is RAL 7035.

Sandblasting is a bad idea. If you must strip, use chemical stripper instead. Maybe you meant plastic media blasting?

tokarnyy_stanok_102_n_cf.jpg
 
Thanks for the info.

True, i used the term sand blasting as a general term for abrasive blasting. I intended to bead blast with glass pearl, but my paint supplier suggested to use a courser media for the primer to have good adhesion. I don't have easy access to plastic media.
Do you see any issues with media like glass pearl or aluminium oxide?
Why would this be an issue if only the painted surfaces are blasted?

Thanks Allot!
 
I intended to bead blast with glass pearl, but my paint supplier suggested to use a courser media for the primer to have good adhesion.

Perhaps your paint supplier doesn't understand that you are working on a precision machine spindle housing?

Anyway, paint adhesion is chemical, not mechanical. Proper cleaning followed by etching will give superior results when compared to surface roughening.

Good painting is an involved multi-step process.

Stripping => Cleaning => Etching => Zinc containing primer => Filler => Topcoat. You can see the layers on your headstock.

A good primer will inhibit the development of rust bubbles under the paint anywhere the surface chips or develops a hairline crack. Rust bubbles are what ultimately undermine the coating adhesion.

Do you see any issues with media like glass pearl or aluminium oxide?
Why would this be an issue if only the painted surfaces are blasted?

You will have to wash the blasted parts to remove any stuck abrasives. Not that much different than washing up after chemical stripper.

A hot pot of caustic water solution would have the paint off in no time with very little effort. The risk there is galvanic action if the pieces in the tank have dissimilar metals in contact.

Sandblasting is so seductive. Its easy to lose control of the process.
 
I'll have a look at the chemical stripping. I like this idea better than blasting but am a bit concerned (no experience so far) about the precision surfaces that come in contact with the chemicals. I'll do some test pieces but as far is i can read about it it does not react with cast iron or steel.

Also will have a look at an etching (primer) like you mentioned.
 
I took a look at the Temacoat GPL-S Primer and saw that it contains zinc phosphate. Zinc phosphate is an etchant for cast iron. Should be good. Looks like a nice system product.
 
Happy to hear your opinion on the coating system. I have no experience on coatings so this was a bit of searching around.
My intention is not to get the lathe done but to finish it as perfect as possible (within limits of course) and learn with doing so. As it's more a hobby project I don't care about how long it will take or how difficult it is.
So your input is really appreciated.

I looked around for chemically stripping the paint and as you mentioned caustic water or NaOH solution woud be the best to do this. I don't mind using chemicals but for the size of the lathe bed I'll have to make a hot tank and it would be difficult to neutralise/discard the waste afterwards. And it doesn't seems to be the most nice chemical to work with.

So i'm thinking now to find a professional paint remover, my concerns are that it will not be possible to prime the parts immediately after they are stripped. I saw they can passivate after stripping but not sure what they use for this. Also I don't like the idea of handing precision parts to a company which probably mainly does fences or other stuff.
I'll call around tomorrow to see what i can find out.

Of course it would also be a solution to mechanically clean up the spots where the paint doesn't cover anymore and then use filler and build a primer on top of that. But I'm somehow more interested to strip it down to the bare castings and start from there.
 
I use this product ==> https://www.sfsunimarket.biz/sfs_do...n__abbeizen_2/SDB_RICO_Farbabbeizer_rapid.pdf

It has the most Dichloromethane content of any over-the-counter stripper I have found available in my country. It works well but slowly, taking several hours to soften underlying paint. Sometimes it takes two or three applications.

Dichloromethane is the useful active ingredient in paint strippers. Regulations have made it harder to find in effective concentrations.

For washing I have large restaurant pots and a hot plate. I think the pots are 50l. They would easily fit a 102 headstock. I use water soluble parts washer solution as a caustic rinse. Avoid having dissimilar metals in contact for any length of time in rinse or washwater because of electrolytic staining.

For cleanup of the process water I add an Aluminium Sulfate flockulant. That causes most colliods in suspension to precipitate into clumps that can easily be removed with a paper filter.

So i'm thinking now to find a professional paint remover,

The risk here is that the outside professional effects one of the many critical tolerances of the part.
 

Thanks, does indeed seems hard to get this. I'll have a look around for it or comparable products and do some test later on.

The risk here is that the outside professional effects one of the many critical tolerances of the part.

Share this concern and think indeed it wouldn't be a good idea.


I'll post some pictures when I move along,
thanks already!
 
I couldn't find any n-Butylacetat strippers or any suitable alternative, at least not easily available.

So I tried a small hot pot with caustic soda and it works beautifully. The paint dissolves in minutes and the cast iron is perfectly clean. I like the results so much that I definitely want to use this method. The only thing I noticed is flash rust building up quite fast after rinsing. So I will degrease and prime coat in one go after stripping.

I'll have a look around for some large stainless tanks tomorrow, i found some brewing kettles that seem a good size to use. And get some more caustic soda and citric acid to neutralise.

@jCandlish:
Thanks for talking me out of bead blasting ;)
This is so much cleaner and controlable

6o0Q1cO.jpg


VQdCGdQ.jpg
 
Found some large stainless brewing kettles of 50l and 100l, should be perfect for making a hot pot for stripping. For now I have everything set up for stripping and priming, I'll probably have time to do it in the weekend after next.

In the mean time another question:
I bought the lathe without the indexing holder and pin, I'll ask prices for spare parts later.
As it seems fairly easy to make one myself, has someone a picture or sketch with basic dimensions?
What's the shape of the indexing pin, is it cylindrical with a conical/concave part?
Is the index pin free moving in the holder or is there a spring action?

Indexing holder/pin as in image bellow (I believe it's the same on all 102 headstocks):

NOZgXiv.jpg
 
As it seems fairly easy to make one myself, has someone a picture or sketch with basic dimensions?
What's the shape of the indexing pin, is it cylindrical with a conical/concave part?
Is the index pin free moving in the holder or is there a spring action?

No need anymore, decided to order a new index assembly as prices from schaublin were acceptable.
Also ordered a new tailstock handwheel and proper plates and spherical washers to mount the lathe on a bench.

Quite impressed by the three point bench mounting with the spherical washers as described in the manual, never saw this setup before. This should put zero twisting forces on the bed when mounting, we'll see how that works out later.

Further had some spray paint mixed in RAL 7035 (the light grey suggested by jCandlish) and RAL effect 810-5 which seemed close to the original colour from the paint chart. Spray painted some test pieces and both colours look great for the lathe, the dark grey is missing a bit of blue compared to the original paint (or whats left of it anyway)

Cant make my mind up on the colour. I prefer the light grey but the dark grey is the original colour.
Anyhow I'll have some work with priming and cleaning the rest of the parts up before I have to choose.

Does anyone know if the RAL 7035 ever originally came on a 102 with a gearbox or reduction headstock?
I'd like to know which colour the inside was painted.
 








 
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