Thoroughly Amateur Staff Replacement

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GeneJockey
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Thoroughly Amateur Staff Replacement

#1 Post by GeneJockey » Sun Jun 03, 2012 7:26 am

Yesterday, I finally had (almost) all the pieces in place to do my first staff replacement. On another thread, Dan said it would be nice to have a step-by-step description, so I have (mostly) documented the atrocities.

IMPORTANT CAVEATS!!! Like I said, this is the very first time I've done this. Also, I don't have a lathe, which is considered the proper way to remove the old staff. Further, I don't have a poising tool, so I had to make do with the poising part of my truing calipers. In other words, this is suboptimal! Kids, try this at home, but not on anything you couldn't replace!

OKAY! For this, I used an Elgin Deluxe that Scott Allison kindly gave me. He'd gotten it in a lot of stuff, IIRC, and hadn't the time or inclination to fiddle with it. It was lacking a stem, and wasn't running. A quick check of the balance and I could see why! pivots gone top and bottom, and no roller jewel!

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BUT, the hairspring was in good shape. I decided to steal the roller table from a 554 parts movement that had a bent hairspring...

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Step 1 is to remove the hairspring. I found a hole in my bench block that would JUST hold the roller table, and dropped the balance into it hairspring up...

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In the background is my homemade collet tool - a heavy-gauge sewing needle, filed to a long screwdriver point, chucked up in a pin vise. Per Fried, you stick the wedge end into the slot in the collet (coming down from above), twist while lifting, and off it theoretically comes. In my case, I ended up VERY CAREFULLY sliding the wedge end under the spring and levering off the collet. I'll explain later why I had to do this.

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Next, removing the roller. The staking set I got from Cary has a roller removing tool. You put the balance in upside down, with the jaws under the roller. Tighten down until the whole thing is held firmly in place.

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Then, with a pivot punch, drive the staff down through the roller.

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Now you have just the balance and staff. You find the smallest hole in the table that holds the balance hub without binding. Use the center punch to center it as perfectly as possible, and place the balance, hub down - so the arms are flat on the staking table.

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Now, place your staff remover carefully over the balance,, unscrew the knurled bit until it reaches the bottom of the gooseneck. There's a special punch for the staff remover. Run it down through the gooseneck and the remover till it rests on the balance staff tip.

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Now, tighten the knurled bit, and using the arm, clamp the head of the staff removing tool down, hold the arms firmly in place.

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One sharp hammer blow, and THEORETICALLY, the rivet is sheared off, the staff pops out, and the balance, clamped firmly to the staking table, is unharmed.

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Sometimes, theory and practice are the same. See the rivet?

So, that's REMOVING a staff. Next post will be about replacing it!
Last edited by GeneJockey on Sun Jun 03, 2012 9:16 am, edited 1 time in total.
http://gjselgins.blogspot.com/

Don't take life so serious, son. It ain't nohow permanent. - Pogo

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N2FHL
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Re: Thoroughly Amateur Staff Replacement

#2 Post by N2FHL » Sun Jun 03, 2012 8:08 am

Perfect so far!

Steve

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GeneJockey
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Re: Thoroughly Amateur Staff Replacement

#3 Post by GeneJockey » Sun Jun 03, 2012 9:10 am

NOW! The old staff is still useful! First thing you need to do is find round-bottom and a flat-faced hollow punches that JUST fit over the collet side of the staff, down to the shoulder.

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Find the smallest hole in the staking table that holds the roller side of the staff without binding, center it with the center punch, and lock it in place.

If you've done your removal correctly, the hole in the balance should JUST fit over the shoulder - mine did - and a little help from a flat-faced hollow punch will push the balance wheel down onto the hub.

Place the staff and wheel into the carefully centered hole, and gently lower the round-bottom punch. You may find you need to readjust the centering - I did.

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Now, with the punch carefully lowered onto the shoulder, strike with the hammer, turning the punch just a little with each blow. After a few blows, press down on the top of the punch, and try to turn the balance with tweezers. This holds the staff in place, and if you've correctly done the riveting, the balance should not turn. It took me three tries with successively sharper blows, but finally the staff was firmly riveted in place.

Next, remove the round-bottom punch and replace it with the flat-faced punch. A few blows will flatten out the rivet.

The roller is replaced by carefully placing it on the staff - it should come down a good bit of the way with a gentle push. Line up the roller jewel perpendicular to the arms. Then the balance is CAREFULLY placed ROLLER TABLE DOWN in the same hole you used when riveting, the flat-faced punch is lowered over the staff, and with EXTREME care, while looking at the gap between the hub and the roller table, light hammer blows push the balance onto the roller. When the last bit of daylight between the roller and the hub disapppears, STOP!!!!

Now it's time to true your balance. Getting the balance into the holes in the caliper is an enormous PITA. There must be an easier way that what I'm doing. Anyway, CAREFULLY place the balance in the truing side of the caliper, which has holes that grip the cones of the balance staff (as opposed to the pivots). Tighten CAREFULLY until the balance doesn't spin freely, but will move easily.

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Adjust the index so that there is a small, but visible bit of daylight between the rim and the index.

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Turn the balance slowly and note whether the size of the sliver of daylight changes. If so, find the high spot, and push it down. In this case, 'high' means that it is high with respect to the top of the balance. Elgin warns against bending the balance UP, since you might undo your careful riveting.

That's truing in the flat. This is a solid balance, so there's not really a lot to worry about truing in the round. But you should have a look anyway.

Now we come to poising. Ideally, you'd have a agate-jawed poising tool. I don't yet, but the truing caliper has poising capability. The other end from the truing part has nibs that hold the pivots of the balance. This part requires extreme care, since you're putting the most fragile part of the balance into the holes, and if you have a brainfart and overtighten, or tighten at the wrong time, or with the pivot in the wrong place, you'll snap off the pivot and rue the day you were born.

Tightening the caliper is tricky. What I did was to get it as tight as possible while still allowing the balance to spin freely. Then I held the caliper so the pivots were level, and noted whether the balance moved. It didn't.

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Just to be sure, I moved the balance a couple times, noting that it turned freely but didn't roll toward one point. The balance would spin freely for a long time, stopping in random orientations, and no matter where I turned it to, it would sit happily, not trying to turn to put a heavy spot down.

This is good, because I have absolutely NO WAY to address poise!

Next I put the balance (still without hairspring) into the movement with the train bridge and pallet removed.

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And gave it a good spin with a brush...

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It spun freely, ran for a LONG TIME, and I detected no wobble, no rubbing etc.

I replaced the hairspring, finished putting the movement together, and wound it up. I had noted where the stud hole in the balance cock was relative to the line connecting the escape, pallet, and balance pivots, so I had an initial read on putting it in beat. It took off running pretty well!

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Put there was more to be done, as it turned out...
http://gjselgins.blogspot.com/

Don't take life so serious, son. It ain't nohow permanent. - Pogo

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GeneJockey
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Re: Thoroughly Amateur Staff Replacement

#4 Post by GeneJockey » Sun Jun 03, 2012 9:41 am

I had previously cleaned the whole movement and put it together up to the balance. then set it aside, BTW, so don't worry that I put a newly restaffed balance back in a dirty old movement.

I used biburo, Audacity, and Etimer to check the regulation, amplitude, and beat error. Timing was okay, beat error not too bad for having been set by guesstimate (8 ms), but I was only getting about 200 degrees of amplitude.

Hmmmm. Did I oil the balance jewels? No.

So, I pulled the balance, oiled the balance jewels and the impulse surface of the pallet stones. Put it all back together, and got 240 degrees. Still not good enough.

I adjusted the collet slightly, and put the balance back in. I had recently picked up a couple NOS Durapower mainsprings for the 8/0 series. I pulled the old spring, put in the new one, and it was turning much better! I recorded a minute, then looked at it on Etimer. Lower beat error, but the trace wandered, and the amplitude was dropping. Indeed, while I watched, it slowed down to barely ticking at all. I was mystified.

I pulled the balance, and noticed the collet didn't seem to be seated. I realized, after pushing it down again, that it was loose. Tweezers could turn it. Loose.

I remembered Fried's chapter on adjusting collets. I got out my staking set, found a concave punch JUST the diameter of the collet. It took a couple hammer blows of increasing intensity before I had finally closed it enough. Put it back on, spent a little time adjusting beat, got that down to 2 ms and STOPPED!

For some reason, even with 270-280 degrees of amplitude, it's running fast - so fast in fact that the regulator is all the way to the slow side. Yes, I've checked the hairspring which is concentric, expands and contracts evenly, and is not stuck together. At this point, at least for the moment, I'm going to bask in the glow of success!

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Oh, yeah! I also had to cut a stem down to size and mount a crown, but that's easy!
http://gjselgins.blogspot.com/

Don't take life so serious, son. It ain't nohow permanent. - Pogo

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HandyDan
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Re: Thoroughly Amateur Staff Replacement

#5 Post by HandyDan » Sun Jun 10, 2012 12:22 pm

Wow!

I feel very humble after reading all that. I know I can cut a stem and fit a crown, but the rest is beyond my skills (and tools) for now.

Excellent post, thanks for sharing!
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trim
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Re: Thoroughly Amateur Staff Replacement

#6 Post by trim » Sun Jun 10, 2012 12:48 pm

Congrats!!!
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ben_hutcherson
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Re: Thoroughly Amateur Staff Replacement

#7 Post by ben_hutcherson » Sun Jun 10, 2012 5:13 pm

Doug,

Great work on this-it's quite a reassuring feeling when you replace your first staff, drop the balance into the watch, and see the balance spin around like a top when you blow on it.

Just a couple of comments-

On an Inverto style staking set, I prefer using an inverted flat faced stake to support the staff rather than putting it directly on the die plate. This saves wear and tear on your die plate, and if you hit it a little bit too hard, you'll just break a $5 stake rather than the die plate.

Also, you may have discovered this already, but on K&D staking sets, the round faced hole punches carry a number exactly 30 higher than the corresponding flat faced hole punch. If the #52(for example) flat faced punch fits the staff correctly, the #72 round hole punch will also fit correctly.

I should add as a side note to this that I keep my two main "working" staking sets arranged with the hole punches on the left side from largest to smallest, and every flat faced punch has its corresponding round punch in the slot right next to it. This makes finding the punches very easy.

(I should also add that I finally got around to staffing your 992 this weekend-sorry for the delay, I've been tremendously behind. I hope to get it sent back to you soon).

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GeneJockey
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Re: Thoroughly Amateur Staff Replacement

#8 Post by GeneJockey » Thu Jun 14, 2012 3:53 pm

I'd like to add that the watch passed 'wear testing' with flying colors, so it's now part of my rotation. And I couldn't be more pleased!

Ben - Interesting thought on using the stake instead of the die plate, but isn't the tip kinda narrow?

Great news on the 992! Looking forward to receiving and wearing it!
http://gjselgins.blogspot.com/

Don't take life so serious, son. It ain't nohow permanent. - Pogo

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Re: Thoroughly Amateur Staff Replacement

#9 Post by ben_hutcherson » Thu Jun 14, 2012 4:48 pm

Doug,

From my experience, the stake is typically just about the right size to support the stump. To give an idea, here's a photo I took a while back of an 1883 model Waltham staff set-up this way

Image

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GeneJockey
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Re: Thoroughly Amateur Staff Replacement

#10 Post by GeneJockey » Wed Jun 20, 2012 8:59 am

I'll have to check the staffs I have - you might be right about them fitting the stake-as-stump well. I haven't tried using the Inverto feature yet, but it's early days, and I'll get to it!
http://gjselgins.blogspot.com/

Don't take life so serious, son. It ain't nohow permanent. - Pogo

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