Thiel 158 clone restoration

[Sonic EscapeParticipant @sonicescape38234]

Last year I bough an FUS250 milling machine. That is a Romanian made machine. It looks like a Thiel 158. Here is the whole story. Until recently I didn’t have time to try to fix it. But now I decided to start to restore it.

The electric part looks quite old and for now I have no desire to check or fix it. For the start I would be happy only to run the spindle and to be able to manually move the table. I didn’t found its manual. I think I’ll order the Thiel manual. I plan to make a Y connection between the motor and the lathes VFD. Inside the motor box I made a useful archeological finding

So I’ll bypass all this ancient electric mess.

I can easily spin the motor by hand. The clone doesn’t have the original’s cone break. It should be no danger to use the VFD. There is no oil left inside. But I think this is not a problem for a few minutes.

So far nothing runs smooth. The machine was not used in decades and the grease from the dovetails solidified. I think I have to make some kind of crane to disassemble some parts. Or for the beginning I could try to spay some acetone on the ways to dissolve the residues? Or WD40?

Anybody has a clue about what this two levers are for? There are two sliding parts on top of the machine. So I suppose there has to be a way so select which one is moving when turning the wheel?

 

[Sonic Escape]

On 24 February 2024 at 14:14 Sonic Escape Said:

… The machine was not used in decades and the grease from the dovetails solidified. I think I have to make some kind of crane to disassemble some parts. Or for the beginning I could try to spay some acetone on the ways to dissolve the residues? Or WD40? …

 

Don’t waste your time !

By fair means or foul, get some PlusGas ‘Formula A’ or whatever kerosene-based dismantling-fluid you can find locally.

MichaelG.

[Sonic EscapeParticipant @sonicescape38234]

It looks like PlusGas is a UK only thing. I’ll give it a try with WD40.

I turned on the motor for the first time and everything seems to be fine! It looks very promising. Now I want to clean the slides. The handling wheels for X and Y axis have an annoying feature. You have push them in the same time when you rotate them. Otherwise they are disconnected from the screw. I guess this is a safety feature.

 

 

[DiogenesParticipant @diogenes]

I think it’s possible that the uppermost slide / overarm is set manually and locked by that lower lever in your picture.

The lower/middle slide is probably the one that moves by the handwheel.?

Does the selector (yellow arrow) on the overarm / upper slide  engage / disengage drive to the vertical head?

[Nigel Graham 2Participant @nigelgraham2]

Acetone would not be a good solvent for this sort of work.

It is very volatile and most would evaporate before it does anything useful – and you need avoid breathing the vapour.

It might also damage the paintwork.

WD-40 will slowly dissolve the old lubricant, but since it is white spirit with a thin oil dissolved in it, I’d simply use white spirit! It may depend what is easier and cheaper for you to obtain.

Brush plenty of the solvent in and leave it overnight to attack the old grease.

….

The label above the upper lever looks as if someone has painted over it. Clean that off to reveal whatever it says, and its purpose may be more obvious.

[Sonic EscapeParticipant @sonicescape38234]

I purchased the Thiel 158 manual and it is very helpful. The lever market by the top yellow arrow is disconnecting the vertical spindle. The horizontal one is always on. The lever indicated by the second arrow is locking the upper saddle. There is a similar one on the other side. Indeed the hand wheel moves both upper and middle saddle. I bought also a bottle of white spirit. It doesn’t evaporate as quickly as acetone.

I cleaned the inside part of the vertical spindle. The bottom was full of dried grease. Unfortunately the part that was not covered is rusty…

I measured the runout of the spindle on the inner surface. The part that is not rusted. The concentricity error is 3μm. I measured also an Aliexpress MT5 ER32 collet holder. Like in this picture:

The runout was 9μm. Either the cheap collet holder is imprecise or the rusted area inside the spindle is ruining the accuracy. In the end I placed also an 8mm mill and I measured close to the collet. The error increased to 19μm. These are normal values?

I also bought one more identical mill. Just in case. It looks like it was used a lot. But it is working.

[Sonic EscapeParticipant @sonicescape38234]

Any ideas how to remove the liquid from the base of the mill? It doesn’t have any evacuation system. There it is a mix of oil, grease, sodium hydroxide and who knows what. It looks like the basement of Chernobyl reactor 4.

 

[Sonic EscapeParticipant @sonicescape38234]

In the last days I made some progress with the mill. First I fixed the bent arbor for Z axis handwheel.

 

Next I cleaned the Y axis dovetail. The top of the machine was sliding only a few cm. It wasn’t used in decades and the oil or grease solidified. Now you can spin the handwheel with two fingers:

Next I wanted to clean the X axis that is also frozen. But this time it is not so easy. I think I have to remove the table and then the horizontal moving part to have a better access to the slides. Also I have access only to a small portion of the lead screw. It is also covered in a solidified lubricant. Somebody even painted them by mistake:

I have a workshop crane but I’m not sure how easy it would be to assemble it back. Those are very heavy parts that have to be aligned precisely.

[Pete RimmerParticipant @peterimmer30576]

Have a look at my FN22 restoration which is quite a long thread as it was spread over a couple of years but it does contain a lot of detail. Our machines are very similar so even though it won’t be identical work it will be along the same lines.

https://www.mig-welding.co.uk/forum/threads/tos-fn22-milling-machine-deckel-clone.117518/

If your table is not moving then you should loosen the tapered gib. Check if it has one adjuster screw on the fat end or one either end and don’t try to force it. The gib will be on the bottom way of that console table.

 

[Pete Rimmer]

On Pete Rimmer Said:

Have a look at my FN22 restoration which is quite a long thread as it was spread over a couple of years but it does contain a lot of detail. Our machines are very similar so even though it won’t be identical work it will be along the same lines.

https://www.mig-welding.co.uk/forum/threads/tos-fn22-milling-machine-deckel-clone.117518/

If your table is not moving then you should loosen the tapered gib. Check if it has one adjuster screw on the fat end or one either end and don’t try to force it. The gib will be on the bottom way of that console table.

 

That is a very interesting thread! So far I had a look only on the first pages and indeed there are some similarities between the two machines. And your dividing head looks exactly like mine. I like that green paint you used. Those parts look perfect. I also want to repaint mine. I’ll make it yellow. But I will just clean it with acetone and paint it over the existing paint. These are some parts from the slotting and dividing head.

[Sonic EscapeParticipant @sonicescape38234]

Is there a way to clean this lead screw without removing it? The bottom half is painted. And the other half is covered with sticky old grease …

[DiogenesParticipant @diogenes]

For things like that I’d use a ‘suede brush’ (a smallish brush with brass wire bristles) and a ‘greasy’ solvent like diesel or white spirit.

Clean it, oil it, run it up and down a few times, wipe off with a rag, re-oil, run it up and etc.. ..until it is clean..

[Diogenes]

On Diogenes Said:

For things like that I’d use a ‘suede brush’ (a smallish brush with brass wire bristles) and a ‘greasy’ solvent like diesel or white spirit.

Clean it, oil it, run it up and down a few times, wipe off with a rag, re-oil, run it up and etc.. ..until it is clean..

Yes, this is working. I didn’t found the white spirit bottle but I have some D5070 solvent. It is very effective. It turned my gloves into a paste. This was also the first time I used an activated charcoal respirator. The filters are so effective that you can’t smell acetone even if the bottle is right under your nose!

I want to start to fill with oil the two main oil baths. But I don’t know how good are the sealings of that vertical shaft. It would be a big mess it will start to leak. Also I don’t want to disassemble this part. It looks to complicated.

I also have an unsolved mystery. I didn’t found yet a satisfactory method to clean the rust. But one morning I found this spot where the metal is perfectly clean. And I don’t know why! None of the chemicals that I’m using could do that (WD40, acetone, rhodiasolv). I don’t remember what I did the previous day.

 

 

[Sonic EscapeParticipant @sonicescape38234]

Now all 3 axis are running fine using the handwheels. There is something wrong with the electrical circuit. Maybe a blown fuse. I don’t have the schematic and I don’t want to touch this part. I’ll bypass everything and use 2 inverters for both motors with a new control panel. I tested the motors and they are working fine.

I removed the first layer of dark green paint with sanding discs. It wasn’t a stable substrate for additional painting. Now the whole workshop is covered with a thin layer of dust. I washed the mill with D509 solvent and then I painted it with a primer and a blue paint. Both are alkyd types. They dry very slow and have a strong smell but are much more durable. Another layer of blue paint is needed. Some parts I’ll paint them with yellow. I like the combination.

 

[Sonic EscapeParticipant @sonicescape38234]

Cleaning and painting all parts takes more time that I imagined. Almost daily I work on this and still I can’t see the progress. And I didn’t even start to work on the electrical part. Or to fill with oil the 2 main oil baths. Also I realized that the whole garage is full of dozens of small parts and I’m not sure I know how to assemble them back in the same order. I never disassembled something so complex and it didn’t crossed my mind to keep some records.

My workshop crane turned out to be a multipurpose tool. Now I have a table on wheels to do dirty work outside. And I can easily move it back when it starts to rain. I found a better paint. The blue one I used for the mill body required 3 coats. With this green one only one layer is enough. It is made by the same company that makes Hammerite. But is half the price. And is quite hard after a few days.

I bought some super cleaning solution. It contains Sodium hydroxide, phosphoric acid, paint stripper and a many more serious chemicals. With a ton of warnings of course. I let some parts in for 2 days but I was not impressed by the results.

I still had to clean the dried grease and paint

 

 

 

[Nigel Graham 2Participant @nigelgraham2]

Good progress though despite the battles with the gunge!

 

Sodium Hydroxide and Phosphoric Acid… Alkali and acid. Interesting blend – I wonder how they don’t neutralise each other?

[Sonic EscapeParticipant @sonicescape38234]

I saw this combination of Sodium Hydroxide and acids also in other cleaning liquids. No idea why they don’t react.

This is the bomb!

But what I used most is this one. In Romania it is available everywhere and is cheap. It contains 10% Sodium Hydroxide. It is a sticky foam. This makes it very effective since it doesn’t flow. But you need good gloves. I had a small accident with it when the glove got punctured. I didn’t noticed and it slowly filled with liquid. I realized after 10 minutes and it was not pleasant.

But I found something that works very well and is not as corrosive as the sodium hydroxide ones. HP12 is recommended even for cleaning the sofa 🙂

[Sonic EscapeParticipant @sonicescape38234]

I cleaned the best I could these two oil baths. Then I remembered that last time when I was in a hardware store I saw a special silicone sealant that is immune to oil. So I thought why not throw away the old gasket and use this nice compound. What could go wrong?

After filling both compartments with 4l of oil I noticed that is leaking! Not to much, only a drop every 20 min. This is so annoying! Now I have to empty both compartments and both evacuation holes are made on a vertical wall, very inconvenient. Suddenly the old gasket doesn’t look so bad anymore …

 

 

[Sonic EscapeParticipant @sonicescape38234]

Today I mounted the table. I don’t know if it has to be aligned, I’ll measure later. There are many things left to do. A few liters of oil leaked from all three oil baths while I was in vacation. The electric part is not ready. The gibs are not adjusted. I can’t find the quill locking screw. But I don’t have patience to finish everything. During all this long restoration process I was tempted a few time to order this new machine. Is not in the same class but at least it is working out of the box.

So today I decided to cut some metal. I connected the main motor directly to the VFD from the other end of the garage. I’m not going to use the power feed motor. I picked a 50mm MT4 two flute mill and a MT4 to MT5 adapter. And a small piece of 20mm thick plate. The depth of cut was between 0.5 to 3mm. The stock doesn’t have a flat surface. Here is the result.

I noticed a few things:

– there is a noise in the spindle while doing heavy cuts. The spindle is the only part that I didn’t opened so far. Or maybe the draw bar washer is ringing. I can’t tell yet.

– at some point the spindle stopped. But to my surprise the motor was still running! My first guess was that a shear pin snapped. I read somewhere that this machine has a few. I stopped the motor, changed the gear and it was running fine! I think there is a problem with this gear changing system. There is no feedback to inform you that the gears are properly aligned. So maybe the gears were engaged only 1mm or so and because of vibrations they moved a little.

– and last, I noticed that on every pass the surface is not on the same level as on the previous (I was using Y axis while cutting). I can’t explain this yet.

But overall I’m very happy with this first test. It is a pleasure to turn those heavy handwheels. And I like the sound it makes. It feels like a serious machine.

 

 

 

 

 

 

[DiogenesParticipant @diogenes]

Does the head need aligning – looks a bit like the spindle is at ’25 minutes to 1′ even in the photo.?

Probably (?should be) detent ?springs and balls? somewhere in the selector mechanism.. ..could be stuck?

Good to see it cutting tho’…

[Diogenes]

 

On Diogenes Said:

Does the head need aligning – looks a bit like the spindle is at ’25 minutes to 1′ even in the photo.?

Probably (?should be) detent ?springs and balls? somewhere in the selector mechanism.. ..could be stuck?

Good to see it cutting tho’…

Yes, you are right about the head alignment! I didn’t notice this. I just cleaned the spidle ring with acetone and under the dried grease I found an alignment mark.

The selector mechanism doesn’t have any spring or balls. I opened that part. An also on the other identical machine I have there is no feedback. Maybe something was lost in the cloning process.

 

 

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