Oberon 21 jewel jump hour, Baumgartner 866 movement

[ManSkirtBrew]

I love jump hour watches, and I couldn't resist this black and white Oberon. Overpaid for it a few months ago as "needs repair," I'm finally tearing into it now.

It looks like the previous owner did the old "soak it in oil to make it run" trick, but it was definitely not running. Came to me fully wound. The balance seemed free, but wouldn't oscillate, so I set about disassembly.

Everything, including the dial, date, minute, and second rings are completely soaked in oil.

 

The main plate is marked BF 866, which looks like Baumgartner's mark.

Now I just have to figure out how to get the barrel open.

 

Well, there's your problem. I don't know what that black crud is, but it was definitely gumming up the works.

[JohnR725]

3 hours ago, ManSkirtBrew said:

The main plate is marked BF 866, which looks like Baumgartner's mark.

Actually it's marked with BFG as the G surrounds everything.

Then these are interesting movements with interesting features. In case you don't have the parts list I'm attaching that. So interesting isn't always good. It's only good if everything works right

 

2529_BFG 866,866.31.7.pdf

[rehajm]

You get to the mainspring just the way it looks- silver lid and wheel up, push down on the edge of the barrel. The big thing here is there will be dried up lubrication in the lid. The link to Jon’s lessons below has what you need to know. I’ve done a bunch of these and if the pivot holes are good (or you get them there) they can run quite well. I followed all of Jon’s Roskopf series..

There’s one more tip that made a bjg difference for me - Ranfft once recommended to use Dr Tillwich blue oil for the pins. A couple drops on the top of the pins and let it run down. Don’t oil the escape wheel teeth. It was good for at least an extra 20 degrees of amplitude vs the recommendation of 9010 or whatever you use on pallet jewels applied directly to the escape wheel teeth…

 

 

Edited September 17, 2023 by rehajm

[ManSkirtBrew]

Thanks for these. I was able to get the center seconds wheel off with the Presto tool I bought for Bulova sweep seconds hand wheels. Finally came in handy again!

But for the life of me I can't get the minute wheel off the lid of the barrel. Even with my largest hand levers and carefully prying only at the center, I can see the wheel flexing as I apply leverage. Any other techniques besides the one shown here?

[rehajm]

1 hour ago, ManSkirtBrew said:

Even with my largest hand levers and carefully prying only at the center, I can see the wheel flexing as I apply leverage. Any other techniques besides the one shown here?

I had not seen using the razor blades when I did it. I recall much twisting and prying at the base like opening a case back, close to the center so I didn't bend the barrel lid.  I used hand levers and some cheap collet levers. The tension comes from the tube where the arbor sticks out of, so I pry at that a bit, too. You have to take a punch to tighten it back up anyways...

I'm sorry to say I know there was at least one where I just left it...

Edited September 17, 2023 by rehajm

[ManSkirtBrew]

While we're here: how would one clean oil from the dial face and various rings? I'm sure solvent + painted dial = sad watchmaker, but I feel like we need something more than water and a q-tip is in order here.

[ManSkirtBrew]

A little more love with the hand levers did the trick. I assume when I rivet this back on later, the minute wheel should not easily rotate on the shaft. The Powerpoint says "Check the friction with each tap" but that could mean a lot of things.

And how about this guy that drives the minute wheel? Should the gears be tighter to each other?

Oh and I just found these guys at the bottom of my benzene jar while pre-cleaning. Wonder where they go?

Edited September 18, 2023 by ManSkirtBrew

[JohnR725]

3 hours ago, ManSkirtBrew said:

Wonder where they go?

Well that does answer part of the question I had I believe it says he of 21 jewels if that is what the dial is implying and typically these watches do not. So in order to have truth in advertising he would have to have jewels someplace in this case based on the shape probably under the dials just above pup the jewel count for proper dial advertisement

[Jon]

On 9/18/2023 at 2:55 AM, ManSkirtBrew said:

A little more love with the hand levers did the trick. I assume when I rivet this back on later, the minute wheel should not easily rotate on the shaft. The Powerpoint says "Check the friction with each tap" but that could mean a lot of things.

When you initially checked the hand setting before anything got disassembled and you thought it was 'Goldilocks'... Not too tight and not too loose when setting the hands, well when you get to the friction-fitted minute wheel, you would turn the minute wheel above the barrel which is friction-fitted in place and 'feel' how tight it is. That is the tightness you want to 'feel' when replacing the minute wheel and using a domed punch in your staking set of the correct size to slightly splay the collar that passes through the minute wheel. That's why it is important to check that tightness on each hit of the punch because if you go too far the hand setting will be really tight, but also you'll need to remove the minute wheel and start again. Knowing that it can be hard to remove the minute wheel, if you have over-tightened it, it will be incredibly hard to remove, hence making those hammer blows light and keep checking the tightness. After you have had the experience of what feels correct a few times, it'll be child's play afterward. remember to check the minute wheel and barrel cover after removing, so that it is absolutely flat before replacing. You can see why the minute wheel needs removing by the amount of old grease in there, by your pic. Most of what I've explained is in the presentations.

The slide I show using razor blades to rest the hand levers on is pretty important, as too much pressure will be put on the barrel cover and bend it. In fact, if you have a washer, cut it in half and that makes a better support, as it will rest on most of the barrel cover.

Edited September 21, 2023 by Jon

[RichardHarris123]

The washer idea is brilliant advice. 

[ManSkirtBrew]

Thanks for the advice! Unfortunately I didn't take note of how it felt before I started, but I used my judgment as if it were a cannon pinion.

My wristwatch winders aren't big enough, so I did have to hand wind the spring in, which is always nerve wracking.

But reassembly continues!

[ManSkirtBrew]

Off to a good start! I'm going to let it run in overnight before I make any changes, but from a non-runner, I'm happy to see this. These are about 10 minutes off a full wind.

Since it's a pin-pallet, I know the amplitude is probably reading wrong. I tried both Watch-o-Scope and PC Timing Machine 3. I seem to remember there was a piece of software that worked better for pin pallet escapements. Anyone know what it is?

 

I also found out where those mystery jewels go. As @JohnR725 guessed, they're just to up the jewel count to 21. Looks like there are supposed to be 4, even though I can only find 3. One goes here:

You can see the brass in the 4 blind holes for them on the dial side of the main plate. Of course, I didn't get a full picture of it during disassembly, so I don't know if I lost a jewel along the line.

 

[rehajm]

12 hours ago, ManSkirtBrew said:

oftware that worked better for pin pallet escapements. Anyone know what it is

Sorry but I do recall a video and/or post what had software that showed ‘pin pallet detected’ or some sort on the screen. Since you have watch o scope and the other- isn’t there open source Tg Timegrapher  for PC? 

I’m in mac world so haven’t bothered…0

 

[ManSkirtBrew]

1 hour ago, rehajm said:

isn’t there open source Tg Timegrapher  for PC? 

I think that's it! I thought I had it bookmarked, but turns out it was the PC Timing machine software.

I'll check it when I'm home, ty.

[ManSkirtBrew]

Well it didn't say anything about detecting a pin pallet, but it does agree with the other two, roughly:

The amplitude looks pretty close based on the super slow-mo, too.

 

[Waggy]

On 9/17/2023 at 11:48 AM, rehajm said:

Use Dr Tillwich blue oil for the pins. A couple drops on the top of the pins and let it run down.

I agree with this and its something I have started doing with most of my pin type pallets, its amazing the difference it makes.

On 9/17/2023 at 11:03 PM, ManSkirtBrew said:

While we're here: how would one clean oil from the dial face and various rings? I'm sure solvent + painted dial = sad watchmaker, but I feel like we need something more than water and a q-tip is in order here.

I have used naphtha in the past, sometimes the print on the dial is soluble in water but not in oil (naphtha) and the naphtha will make short work of the oil. But, try a little on a small part that won't be the end of the world if it damages anything, if you are lucky it will be OK, if not then you may have to live with the dial the way it is.

Edited September 25, 2023 by Waggy
Typo

[Malocchio]

On 9/18/2023 at 4:55 AM, ManSkirtBrew said:

And how about this guy that drives the minute wheel? Should the gears be tighter to each other?

 

I have this one BFG jump hour watch with a part that works like a cannon pinion. At 55 minutes the wheels started slipping and the hour wouldn't advance altough the movement was otherwise running fine. Had to tighten it to get working properly. 

[ManSkirtBrew]

Well, looks like the minute wheel isn't tight enough. It sets easily and runs well, right up until it has to jump the date. Then the seconds hand spins but the rings don't turn.

Ah well, live and learn.

[ManSkirtBrew]

Okay, took the bridge off, barrel out, and tightened up the minute wheel. Seems to be working so far, but we'll know tomorrow.

For now, I cleaned up the case and polished out the crystal, which badly needed it.

The second hand was pretty well bent, so I gave it a gentle straighten. It also needs to have the circle re-filled with red paint. What would one use for that?

Then I happened to have a nice brown leather band to try out, and I like it. I'm thinking it'll look even better with black leather.