Jump to content

Gruen 415 - Erratic Timegraph after Service/Balance Replacement


Recommended Posts

I have this Gruen 415 that I got as a non-runner.  I did a service after seeing no real issues and unfortunately, when reassembling the balance after lubricating the cap jewel (this is not shock protected and you have to pull the balance to undo the screws to release the jewel), I dropped the balance and twisted the hairspring pretty badly.  I found a replacement and installed it, and it fired right up, but it's running quite slow as you can see in the photos.  Even when I max out the adjustment it is still roughly 100 sec/day slow.  Beat error is OK once the adjustment arm is maxed but climbs as you move the adjustment arm to the middle of the range.  Amplitude is OK, maybe a bit low.

I've messed with the hairspring a bit to try to get it correct.  I removed the spring and put a slight bend near the regulating arm and that helped a bit.   Originally it was bunched to one side and I found that I had also bent the regulating pin slightly when putting it back together.  Once that was straightened out, it ran better but the hairspring was not (and still isn't) "breathing" the way it should.  Basically the spring looks great towards the bottom of the balance cock, but the top side isn't really moving at all.  I'm not sure how to rectify that as it seems that something is impeding the spring at the regulating end of the balance.

Any ideas?

415_balance.JPG

415_movement.JPG

415_Timegraph.JPG

Link to comment
Share on other sites

21 hours ago, SAK335 said:

I found a replacement and installed it,

Just to be clear you replace the hairspring or the balance complete?

It always nice to give us more than one position on the timing machine like it's a wristwatch maybe crown down that's a common position.

Then fixing hairsprings requires a lot of practice. Preferably practicing on junk hairsprings before you have to practice on the real thing.

21 hours ago, SAK335 said:

Beat error is OK once the adjustment arm is maxed but climbs as you move the adjustment arm to the middle of the range.

I'm a little confused here? It looks like you don't have a movable arm for the beat error? Then it is not really acceptable because I don't actually think the numbers are technically correct anyway. We deal we get a better idea if you put a crown down position but the lines look to rough the  it doesn't quite look right and you do need to straighten out the hairspring before he can deal with any of this.

 

Link to comment
Share on other sites

To be clear, I replaced the complete balance because it was what I was able to find.

Yes, the watch has a non-moveable stud carrier.  I mention beat error because if you move the adjuster, the beat error changes pretty dramatically.  When it's all the way to the "slow" side, the beat error is over 5ms, but if you move it all the way to the "fast" side it's like 0.5ms.  I thought that might be information that might help figure out what is going on here.

I've taken more timegrapher photos.  From top to bottom they are: Crown Down, Crown Up, Dial Up.  The original timegrapher photo was Dial Down.

 

CrownDown.JPG

CrownUp.JPG

DialUp.JPG

Link to comment
Share on other sites

The hairspring needs to be adjusted at the stud, and then along the first coil past the regulator to be concentric with the balance center. It's way off, this is what's giving you your beat error change. You can probably see the spring body shifting as you move the regulator now. For the slow rate, check that the regulator pin is straight and close to the "boot", there should only be about 1 hairspring thickness of freedom (or less in many cases).

 

To adjust the spring from the stud, it would be best to remove the hairspring from the balance, install it in the overturned cock, and adjust. When you are happy with the curve that the regulator follows, you will most certainly need to make a new adjustment at the end of the regulating curve to center the spring. The collet hole will be directly over the balance jewel when it's good.

 

In the pic you can see a circle concentric with the balance center, and an approximation of the bends necessary at the stud, and where to make the additional centering bends at the red arrow.

 

 

gruen 415 mod.jpg

  • Like 1
Link to comment
Share on other sites

13 minutes ago, nickelsilver said:

In the pic you can see a circle concentric with the balance center, and an approximation of the bends necessary at the stud

So in this case it doesn't seem possibile to have a constant circle section between stud and regulator? I was thinking that they should be equidistant from the center to allow that.

My other comment is that the OP should reverse whatever he did to the previous pictures, in the last ones the amplitude is so low that all numbers are meaningless in my opinion.

Link to comment
Share on other sites

2 minutes ago, Klassiker said:

It looks as though the hairspring is fouled on the centre wheel.

I just looked, as I've had that happen on another watch, but there is plenty of clearance between the spring and the wheel.

Link to comment
Share on other sites

25 minutes ago, nickelsilver said:

For the slow rate, check that the regulator pin is straight and close to the "boot", there should only be about 1 hairspring thickness of freedom (or less in many cases).

OK, understood.  I mentioned that I bent this when I first installed the balance complete, and had to straighten and bend it back, so it's quite possible I've not gotten it adjusted correctly.

26 minutes ago, nickelsilver said:

To adjust the spring from the stud, it would be best to remove the hairspring from the balance, install it in the overturned cock, and adjust. When you are happy with the curve that the regulator follows, you will most certainly need to make a new adjustment at the end of the regulating curve to center the spring. The collet hole will be directly over the balance jewel when it's good.

OK, I've seen a couple videos of this being done, so I'll rewatch and see what I can do.

  • Like 1
Link to comment
Share on other sites

24 minutes ago, jdm said:

So in this case it doesn't seem possibile to have a constant circle section between stud and regulator? I was thinking that they should be equidistant from the center to allow that.

My other comment is that the OP should reverse whatever he did to the previous pictures, in the last ones the amplitude is so low that all numbers are meaningless in my opinion.

It can definitely be made concentric, like in the pic. Tons of watches have the stud on a different center than the regulator, with appropriate bends to the hairspring to center the regulator curve.

Link to comment
Share on other sites

52 minutes ago, Klassiker said:

Does the hairspring now have the shape described by Nickelsilver above?

The spring is moving back and forth underneath the wheel.  It just so happened that when I took that photo, the spring had moved "in" and looked as if it had aligned with the wheel.

Link to comment
Share on other sites

2 hours ago, jdm said:

My other comment is that the OP should reverse whatever he did to the previous pictures, in the last ones the amplitude is so low that all numbers are meaningless in my opinion.

Did you notice the first picture the amplitude looked really good in fact it looked too good for what were seeing? This is why always ask for a second position like crown down because if there is a amplitude reading issue a lot of times will show up in another position.

Then all the rest of the pictures basically show random dots so all it's really telling us is you're having a problem and until you get the problem to go away the timing machine is now worthless other than it's telling you you're having a problem

Basically this means you have to fix the hairspring problems and the timing machine problems should go away. Also make sure the hairspring is flat and not touching the balance arms.

 

Link to comment
Share on other sites

15 hours ago, JohnR725 said:

Did you notice the first picture the amplitude looked really good in fact it looked too good for what were seeing? This is why always ask for a second position like crown down because if there is a amplitude reading issue a lot of times will show up in another position

I think you mean the reading is double the actual amplitude. Whilenrhat is surely possible, some elements don't match. In first pic with double reading actual could have been around 120deg, with discernible slow and poor pattern. Then last picture, low amplitude for sure, rate all over the place, no pattern.. meaningless. So I wonder if anything has changed in between.

Link to comment
Share on other sites

The amplitude was actually really good when I first installed the balance (after fixing the issue with the balance adjuster pin) and the lines were straight-ish.  But the watch was running super slow.  I made a very minor adjustment to the hairspring near the stud to try to get the hairspring rounder, and the amplitude dropped down into the mid 100s as a result.

Link to comment
Share on other sites



  • Recently Browsing

    • No registered users viewing this page.
  • Topics

  • Posts

    • One way is to file it by hand. Good file with sharp edge is needed. Another way is with the aid of milling attachment. There is one more way, thyat is really only on the lathe, but the arbor has to be attached perpendicular to the axis of the spindle. Will be easier to show pictures than to explain this.
    • giving up so soon? then the feelings of frustrations is common for all of us. At work I've requested a cannon? To be technically correct I like to get a black powder cannon as I think I be quite enjoyable to fire some of the watch movements off into the distance never to be seen again unfortunately I don't think I'm going to get my request. So yes we all have frustrations like I have a frustration with this discussion I don't suppose before you run away you could give us the size of the movement and a photograph of the dial side with the keyless parts.  as I'm still rather curious about who made this watch.
    • It wasn't a rookie mistake Nev , i should have know better with me being a joiner. After a hole another a wider bit has nothing to keep it to center and the outside of the flutes draw the drill bit in fast because of no material present. I must have done it thousands of times in timber and plastic . It was a senior moment mistake. 😄
    • Don't give up. You just need patience and practice. Don't use force or try to screw down the plate before making sure everything is in place. My first few watches took me like 45 minutes to get the train wheels in. Now it usually takes me less than a minute. Make sure that all the bottom pivots are in their respective holes before putting on the top plate. Then apply gentle pressure with a pegwood or gloved finger. Start from the barrel, 2nd wheel, 3rd wheel.... and finally the escape wheel. You can feel the plate drop each time you get a pivot in. If you experience the pivots that you have already gotten in coming out of their holes when you work on other wheels down line, you can put 1 or 2 screws nearer the barrel side in but don't exert any force on the screws. Just lightly turn the screws until you feel pressure and backoff 1/4 turn. This will prevent the plates from separating.  I use a homemade tool with a brass wire, shaped like an oiler to lightly touch the wheels to guide them into place. I find that an oiler made of hardened steel can leave scratches on the brass wheels. Once you think you have gotten all the pivots in, test it by using a blower to blow on the escape wheel. It should spin freely. Continue applying pressure on the top plate with the pegwood or finger until you lightly tighten all the screws. Don't tighten fully yet until you reconfirm that the wheels are able to spin freely. And reconfirm again after you have fully tightened all the screws. What you are experiencing is normal. All of us have gone through it. Don't work on watches when you are tired or frustrated. All of us can tell you what that leads to. But I'm sure you'll experience a few hard lessons even after reading this advice. It's only human. Go forth and practice. Good luck!
    • by the way this is very confusing to me? You have a 7s26a and you're comparing it to a 7s26b which is confusing to me because they're not the same? Watch companies are rather amusing when it comes the part numbers seemingly watches with similar  numbers as you're implying should be exactly identical but in this case they are very very dramatically different for instance the 7s26a balance part number is 0310 020 the 7s26b has a different part number 0310 197 as the part numbers are entirely different there must be a reason it noticed that I made two terms in the quote above in bold regulator pins are versus the etachron  system. In addition to changing the regulation part more than likely they change the hairspring. So this would typically main you wouldn't build a swap balance completes from one type to the other because they will be entirely different. this is where looking at the technical guide might yield some amusing information. you'll note in the 7s26b  service guide it explains what the difference is. It makes a reference to the balance staff which is totally inconsequential for this discussion. But the really big difference is the A  version has conventional regulator pins and the B  has is the Etachron  system. In @Jon excellent images up above he didn't explain something? if you look carefully at the images below you'll notice that the outer terminal curve is different  as a guest to accommodate the etachron  system it looks like the terminal curve is farther out. So yes exactly as the parts list indicates the balance completes will look different because they are different. Because they are different there are not interchangeable. so basically because the letter changes at the end in this particular case we end up with two separate balance completes as proven by the parts numbers. Balance completes that are entirely different to accommodate the regulation system conceivably with entirely different characteristics of timing as they are entirely different. So your observation of the balances are different shape is correct they are different.      
×
×
  • Create New...