No power at pallet fork

[EdB]

New to horology, working on my first movement. 

eBay purchase,scrap practice movement AR 1010, ran originally but very poorly based on time Grapher. Had rust, cleaned twice by hand and ultrasonic. Used microscope to examine all parts. During reassembly I broke pallet staff, ordered replacement from India, when it arrived I visually compared it to original and it appears to be the same. Installed but will not snap to either of the banking pins. Spring winds fully, free movement of all train wheels and barrel with bridges installed. I checked end play of the pallet fork and it seemed to be ok. At a loss for solutions. I also tried loosening pallet cock to see if there wasn't enough end play, but didn't have no effect.

Any and all help would be appreciated.

[Nucejoe]

Check and compare the pivot cones on old and new fork arbour.

 

 

[watchweasol]

As Joe's remarks also check the stones for shape and size might look ok visually but a micron or two will make all the difference in the lockings.

[Nucejoe]

Visual comparison of pivot's OD on new and old arbours is near impossible, I guess they are the same or about the same, since the new pivot did fit into the jewel, if the fork doesn't move freely something is wrong there. common causes are; craked jewel, thick or bent pivots, coned pivot fitted into flat jewels. 

 

[JohnR725]

12 hours ago, EdB said:

visually compared it to original and it appears to be the same. Installed but will not snap to either of the banking pins.

I don't recognize your movement number and you don't have any pictures so I don't know how old it is? Watches like American pocket watches for instance usually have the pallet fork adjusted to each watch. Even if they catalog said they were mass-produced there were usually adjusted.

If you're pallet fork is brand-new factory new versus coming out of another watch it should probably work. But there's a reason they still have shellac on pallet forks so that the depth the lock can be adjusted. If your stones are out too far then you cannot unlock which may be the problem you are experiencing.

But I cannot tell from the wording whether it's a locking problem or a pivot problem? I see that Nucejoe As commented the same thing above. You could disassemble the watch only put the pallet fork in and verify that it moves with zero friction. Unfortunately because the really tiny dimensions it's often hard to measure the pallet fork to see if its difference in size you can only really tell by how it feels in the watch. Getting rid of everything else he can only deal with the pallet fork would help.

[EdB]

Gentlemen, 

I've compared both pallet forks side by side under magnification and found the following. The arbor of the new pallet fork is longer and is conical as it forms the pivot, whilst on the original both arbors appear to be flat with a slight chamfer with the shoulder being square where the pivot begins. 

I will attempt to source another pallet fork and see if the problem is resolved. 

I also re-inspected the jewels and they appear to be fine.

I will follow-up with a photo to show findings, if I can figure out how to connect microscope to computer. 

Thanks everyone for your assistance tracking down the issue. 

[Nucejoe]

11 hours ago, Nucejoe said:

Check and compare the pivot cones on old and new fork arbour.

 

 

What made finding the fault easy for me, was your excellent description of the symptoms.

Best wishes

Joe

 

[EdB]

Thanks Joe!

[JohnR725]

The problem you have comes up typically with escape wheels. A lot of times escape wheels will have a conical pivot on one side usually the visible side where there's a end stone. To understand this problem I snipped out a page from the bestfit book.

Then there is another way to fix the problem? Unfortunately requires the proper tools and that would be you can change the pallet fork arbor. There are either available aftermarket made to specific size or depending upon the watch we can look up and get an actual part number.

[JohnR725]

I have a link to a parts list for your watch and some information. Plus I snipped out an image notice that there are two pallet forks? Strangely enough there is only one pallet arbor?

What's interesting on the parts site is if you click on the link to the pallet fork itself it only replaces or goes in three other watches. But if you click on the  arbors are more universal. This means that getting a replacement arbor would be no problem getting it in without the right tools will be. Looks like the pallet fork arbor is in stock that's the third link.

http://cgi.julesborel.com/cgi-bin/matcgi2?ref=ENI_1010

http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&&2uswk&Enicar_1010

http://www.julesborel.com/s.nl/it.A/id.27013/.f

 

[EdB]

Thanks for the info John, I don't currently have the staking set to perform this type of work. I have added a few pictures of the pallet forks side by side. I did have a clear scale that will show the difference in length of the arbor as well as the pivot itself. The pivot should not be an issue even though it's a bit longer since the jewels are open on both the top and bottom. 

I do appreciate the help from everyone! I am amazed at all of the support.