It's okay, but you have to understand that there are differences in movements - if this was a Cal. 1864 we would be looking at very different requirements than with an 1861.
So with the Cal. 1861, this is a non-chronometer movement, so as with any Omega non-chronometer movement, the timing checks are done in 3 poistions only for Omega specs (note that for every watch I service, I always check 6 positions at full wind regardless of the movement, but that's just me being picky). When looking at the requirements from Omega, the reference is Work Instruction 28, so these numbers come from that document.
So this watch beats at 21,600 vph, the lift angle is 50 degrees, the maximum allowed beat error is 0.6 ms. Note that setting the lift angle correctly is quite important, as the balance amplitiude is a calculated value using the lift angle. Rule of thumb is that for every 1 degree error in lift angle, there is a 6 degree error in balance amplitude readings. Most machines default to 52 degrees as this is what Rolex uses, but Omegas can vary quite a lot from that - some as low as 36 degrees, and some as high as 54 degrees.
The three positions you check for this movement are CH (dial up), 9H (crown down), and 6H (crown left). The first check I do after service is to test the minimum balance amplitude, and this is done at full wind -24 hours. So since you are not able to let the mainspring down, you would need to fully wind the watch, let it run for 24 hours, and then put it on the timing machine. Check it in the three positions above, and the balance amplitude should not be below 190 degrees in any of those three positions. Note that due to frictional losses, the lowest amplitude should always be in a vertical position, so either the crown down or crown left positions.
So for each position, note down the balance amplitude, average rate, and beat error. So when you are done, you would have 3 readings like this:
Dial up - 220 degrees, +5 s/d, 0.3 ms
Crown down - 190 degrees, +1 s/d, 0.2 ms
Crown left - 195 degrees, +6 s/d, 0.3 ms
Note that your numbers may be significantly different from these, and these are just examples.
So how to perform these checks - place the watch on the microphone stand, and Omega states the stabilization time for this movement at 30 seconds, and the measurement time at 20 seconds. This means after you place the watch on the stand, or move the watch from one position to another, you need to leave it for at least 30 seconds to stabilize the readings. I typically use 1 minute for this to be safe. Then you need to take the measurements over a period of 20 seconds, and again I usually use a minute to be safe. So place the watch on the machine dial up to start, let it sit for at least 30 seconds, and when that time is up, start counting off 20 seconds. At the end of 20 seconds look at all the numbers and write them down. Switch to the next position, and then repeat, making sure to let the watch stabilize after each change of position. Please post your results here in this thread.
When you have completed this check, we can move on to the next series of checks. In the context of a service, if the watch fails to meet this minmum balance amplitude specification, it would have to be disassembled and repaired so it did meet this, or there is not much point in moving on.
A quick word on balance amplitude, and how most timing machines measure it. As most of you likely know, the balance amplitude is the measure of how far the balance wheel swings. What many people (even some watchmakers) don't fully undestand is how the machine displays this information. As noted this is a calculated value using sounds from the escapement and the lift angle. The bit that eludes most people is that the number displayed on the machine is actually an average. The balance wheels swings in one direction, then reverses and swings in the other direction, and the number displayed is an average of those two readings. So for example the wheel may swing say 270 degrees in one direction, then 280 the other, and the machine will display an average of 275. It's important to understand this when we talk about maximum balance amplitudes later on.
Cheers, Al
