BFG 866 power not getting to the escapement

[AndrewR]

My first attempt with this particular movement didn;t end well. Long story short (long because of siring those pivots), the mainspring wasn't grabbing the arbor hook, and in trying to tighten the end of the spring I broke it.

So moving on, I took a barrel complete from another 866 and inserted this into the movement after checking it could take a wind.

After a shorter period resiting the pivots (hooray), checking the wheels ran smoothly, I reinstalled the pallet (I thought I checked the pallet snapped over), and the balance. But the watch will not run.

It WILL run if I apply pressure to the crown as if winding (but it's now fully wound), or directly to the barrel.

Things I've checked;

• Demagnetised
• Check balance coil is concentric
• Pivots all sited and wheels move
• Setting works well, not too stiff, not too lose (from Jon's tutorial)

So before I pull it apart again and dig into the barrel (and subsequent reassembly), I wanted to check if I was missing something?

[nevenbekriev]

You can be more than sure that this movement is NOT MAGNETIZED as the escapement/balance are made of non magnetic materials . No point to use demagnetizer.

No point to disassemble and then again assemble the whole movement as it is obvious that You will not be able to find what is wrong this way. What You need to do is some tests that will show how different functional groups work. Remove the balance and see how the lever 'snaps' from side to side. If not as expected - remove the lever and see how free the train unwinds. At this point You can put balance back (without the lever) and do the free oscillations test.

[AndrewR]

1 hour ago, nevenbekriev said:

You can be more than sure that this movement is NOT MAGNETIZED as the escapement/balance are made of non magnetic materials . No point to use demagnetizer.

No point to disassemble and then again assemble the whole movement as it is obvious that You will not be able to find what is wrong this way. What You need to do is some tests that will show how different functional groups work. Remove the balance and see how the lever 'snaps' from side to side. If not as expected - remove the lever and see how free the train unwinds. At this point You can put balance back (without the lever) and do the free oscillations test.

Thanks Nevin. Interesting about being non-magnetic!

I have done the pallet snap test I said above. Same effect as having the balance. Works when putting force on the crown (ie trying to wind it), but nothing otherwise. I state that I thought I'd tested this as part of a normal reassemble routine, so can't understand why it doesn't now.

By lever I assume you mean the pin pallet. I'll give that a shot. I might let the spring down a bit first as it's full wound.

[AndrewR]

1 hour ago, nevenbekriev said:

You can be more than sure that this movement is NOT MAGNETIZED as the escapement/balance are made of non magnetic materials . No point to use demagnetizer.

No point to disassemble and then again assemble the whole movement as it is obvious that You will not be able to find what is wrong this way. What You need to do is some tests that will show how different functional groups work. Remove the balance and see how the lever 'snaps' from side to side. If not as expected - remove the lever and see how free the train unwinds. At this point You can put balance back (without the lever) and do the free oscillations test.

Thanks Nevin. Interesting about being non-magnetic!

I have done the pallet snap test I said above. Same effect as having the balance. Works when putting force on the crown (ie trying to wind it), but nothing otherwise. I state that I thought I'd tested this as part of a normal reassemble routine, so can't understand why it doesn't now.

By lever I assume you mean the pin pallet. I'll give that a shot. I might let the spring down a bit first as it's full wound.

FEEDBACK

Pulled the pallet and the mechanism didn't wind down.

I manipulated the barrel and the power then came through. Rewound, tried again, same reluctant delivery. Rewound and then it delivered the power. Rewound and it didn't.

It's as if there's some inertia that needs to be overcome before the power comes through.

Then I tried t check if there was too much pressure from the bridge, and releasing some tension from the post where the click stop is, the spring wound down.

This leads me to believe that;

perhaps this bareel isn't exactly the same as the one I took out (this came from another 866),

or the barrel isn't perfectly sited into the plate

or there's somethign wrong with the mainspring/barrel (nb. I didn't celan these as I wanted to check it worked first).

[nevenbekriev]

When putting force on the crown, You overcome some kind of resistance and it is due some kind of unwanted friction. A lot of badly working movements will work better when additional torque applied. But this will not help understand where the problem is, just shows something is not in order.

Yes, by lever I mean the 'pin pallet'. But when word 'pallet' is used, I refer it to the pallet stone, which is not present in this specific part. Of course, my understanding of english names of the parts may not be fully correct. What I would use is 'pin lever'.

Now, Do I understand right that the lever doesn't snap well if no additional torque applied? If so, then investigate the train and barrel. Yes, You should release the spring and when the lever is out, wind again to see what happens.

Well, make marker dot on the barrel and see if when movement seized, the barrel is always in the same position. Look around if some screw is longer than needed and touching the barrel.

There is always some free play in the mesh of wheels/pinions. When the movement is seized with wound spring, try checking wheels for free play of the mesh. Thus You will come to a wheel(s) that won't have such free play as there is torque applied and to such that have free play of the mesh and no torque is applied to them. The reason of seizing then must be where the first wheel with no free play is.

[AndrewR]

So I ended up stripping the movement down again and having a look at the barrel. I measured this one and hte one I'd removed and they were the same dimensions. I took the lid off to check everythign was OK inside. I checked the rotation of the attached wheel as per Jon's walkthrough and it seemed OK, not to tight, not to slack.

What I think might have been the issue was the barrel lid. I suspect that it wasn't fully engaged because this time I had to use more force than I recall last time. That would explain the "friction" if it were pushing outwards into the plates.

Anyway, a couple of firm clicks later and we have a running watch ladies and gentlemen. Hooray. Now all that's left is the regulation.

At first the amplitude was poor, but I managed to get the rate vaguely on line. BE was poor I gave it a little puff with the blower and it really picked up. The amplitude and the BE were looking great. But now the rate is <-999 and I'm running out of room on the regulator. I suspect I need to let it run for 24 hours and let the oils bed in.

[GPrideaux]

Does the arbor have any end-shake in the barrel? Does the barrel have any end shake between plate and bridge? Is the lid properly seated all the way around the barrel?

[Neverenoughwatches]

14 hours ago, nevenbekriev said:

Yes, by lever I mean the 'pin pallet'. But when word 'pallet' is used, I refer it to the pallet stone, which is not present in this specific part. Of course, my understanding of english names of the parts may not be fully correct. What I would use is 'pin lever'.

This paragraph set me thinking as to where the name pallet fork comes from. I like Nev prefer the old  traditional name " lever".   Pallet fork is a relatively new term, 100 years ?...a fork at one end and a pallet at the other, Wikipedia even got that wrong.  " Fork"  is easily explained visually , but what about " pallet "...an early English explanation of " pallet " is a straw bed...which is likely where another explanation of a platform also comes from. A wooden pallet for carrying goods is also a platform. So a "pallet" ....a bed or platform that carries the ruby stones of the "lever"

I'm with Nev on this, Cheap movements such as this only have holes in the plates for wheel pivot bearings. Wear can be heavy in these holes right from the barrel up to the escapewheel, turning round holes into oval holes. Excess sideshakes in the train would  cause poor meshing and binding of wheel teeth and pinions.

[AndrewR]

9 hours ago, GPrideaux said:

Does the arbor have any end-shake in the barrel? Does the barrel have any end shake between plate and bridge? Is the lid properly seated all the way around the barrel?

Thanks GP,

I found it prior to your reply but it was indeed the barrel lid not fully engaged - at least I strongly suspect. Watch is running strongly, although I haven't timegraphed it since last night yet.

[AndrewR]

5 hours ago, Neverenoughwatches said:

This paragraph set me thinking as to where the name pallet fork comes from. I like Nev prefer the old  traditional name " lever".   Pallet fork is a relatively new term, 100 years ?...a fork at one end and a pallet at the other, Wikipedia even got that wrong.  " Fork"  is easily explained visually , but what about " pallet "...an early English explanation of " pallet " is a straw bed...which is likely where another explanation of a platform also comes from. A wooden pallet for carrying goods is also a platform. So a "pallet" ....a bed or platform that carries the ruby stones of the "lever"

I'm with Nev on this, Cheap movements such as this only have holes in the plates for wheel pivot bearings. Wear can be heavy in these holes right from the barrel up to the escapewheel, turning round holes into oval holes. Excess sideshakes in the train would  cause poor meshing and binding of wheel teeth and pinions.

Cheers NEW,

Etymology can be as deep a rabbit hole as watchmaking

Everything seems pretty tight. As per previous replies I suspect the issue was a "loose" barrel lid, and the watch is running strongly now. Thanks

[Jon]

47 minutes ago, AndrewR said:

Everything seems pretty tight. As per previous replies I suspect the issue was a "loose" barrel lid, and the watch is running strongly now. Thanks

There's a gift right there.... Always check your work before proceeding. Failure is my best teacher. You won't make the mistake of not checking the barrel cover now, so it was an invaluable lesson.

Another great lesson is removing the train bridge without letting the power down. You only do that once!

I'm glad you found the walkthroughs helpful. I used to teach the set of lessons to my first year cohort, but this year I've decide to drop the BFG 866 from the curriculum because most end up hating the watch that they are working on usually due to wear. There's some great lessons to be learned from them, like the wheel train layout, bringing it into beat by spinning the collet, friction fit with staking tool the minute wheel and ultimately understanding why Roskopf watches aren't made today and seeing the differences between pin-pallet and Swiss lever escapements.

I've decide to replace the BFG lessons with using a watchmaker's lathe to hand-turn Delrin hand pushers (just as good as Horotec 50 quid set!) and probe sticks, as well as making an EtaChron stud removal tool when we start to make hand levers and a spring-bar removal tool, so it will be four to five weeks of tool-making instead, which the class are very happy about.

I'm a bit sad to let go of the BFG, but even I started to dread every year the parts tray coming out ready for the onslaught of pin pallet madness.

I take my hat off to you for bringing this one back from the brink Well done!

[AndrewR]

6 minutes ago, Jon said:

There's a gift right there.... Always check your work before proceeding. Failure is my best teacher. You won't make the mistake of not checking the barrel cover now, so it was an invaluable lesson.

Another great lesson is removing the train bridge without letting the power down. You only do that once!

I'm glad you found the walkthroughs helpful. I used to teach the set of lessons to my first year cohort, but this year I've decide to drop the BFG 866 from the curriculum because most end up hating the watch that they are working on usually due to wear. There's some great lessons to be learned from them, like the wheel train layout, bringing it into beat by spinning the collet, friction fit with staking tool the minute wheel and ultimately understanding why Roskopf watches aren't made today and seeing the differences between pin-pallet and Swiss lever escapements.

I've decide to replace the BFG lessons with using a watchmaker's lathe to hand-turn Delrin hand pushers (just as good as Horotec 50 quid set!) and probe sticks, as well as making an EtaChron stud removal tool when we start to make hand levers and a spring-bar removal tool, so it will be four to five weeks of tool-making instead, which the class are very happy about.

I'm a bit sad to let go of the BFG, but even I started to dread every year the parts tray coming out ready for the onslaught of pin pallet madness.

I take my hat off to you for bringing this one back from the brink Well done!

Cheers Jon,

There was a lot of swearing on the initial reassembly video - lol. But from 2 hours to 30mins to 15 mins, I'm hoping it's learning and not luck

I haven't regulated it. It's a bit off on the timegrapher. I might need to strip, wash, reassemble and lube again. Then I'll look to collet work. although the eyeball view looks like it's positioned between the pins, just a case of how deviant. I've got a few of them so I need the practise... Such an interesting movement as you say, and most of these are powering on, albeit a little roughly.

This was actually the second as I replaced the balance from a partial movement into the blue Omnta and that's working well. It will need servicing though.

Thanks for your support - before and after!