Daisy Dial Train Puzzle

Dear Clayton,  I have a small issue with the Daisy Dial Train on my Mantis. The hour hand consistently stops at about 4:00. It happens pretty much every time that the hour hand attempts to pass roundabout 4:00. 

Since this is consistent, I figure that there is probably a known solution, and maybe this is common. 

The only item that comes so mind for me is the balance of the hour hand. If the hour hand isn’t well balanced, and the short end of the hour hand is heavier, this might explain the consistent stopping at 4:00. Thoughts? 

Just wondering about this. Since it’s so consistent, maybe you have a quick solution? 

Clayton's response:  Aloha.  I'm happy to help.  As you know, the Daisy Dial Train is such a wonderful and unique part of many of my designs - Radiance, Mantis, Balance, SwingTime, Tempo - all use the Daisy Dial Train.   It is such an excellent dial train for very quickly setting the hands to the correct time. 

I think your guess is a good one about the Hour Hand's counterweight end being just a bit heavy, and that should be checked out.  

Checking a hand's balance is easily tested by removing the hand and running a rod through the center hole of the hand and giving it a spin.  When the hand stops spinning, the heavy part of the hand will be pointing at the floor.  Then to balance, remove some wood from the back of the heavy end, or add some weight to the counterweight end.  

However...my first thought was not of the Hour Hand counterweight.  It was instead of the Daisy itself and its interaction with the pins coming out the back of the Tri. 

A most common cause of the Daisy Dial Train not working properly at first is that the pins get stuck on the Daisy's bump as they are trying to pass over.  Once the reason is found and fixed, the Daisy can continue to give decades of flawless motion. 

This sticking of the pin on a bump can be caused by a too-large, or unsmooth bump.  Or it could be that the drilled dowel, that is the Cam of the Minute Hand, does not have enough lift to get the Tri's pin smoothly over the bump.  Here is a screenshot from the bottom of the Minute Hand assembly page that explains... 

 Alternatively, an Hour Hand consistently getting stuck at one point on the dial could be something as simple as the Daisy bump needing a bit of lubricant. 

Since it is such a simple thing to investigate, that is where I'd begin looking. 

I'd first see what pin/bump is getting caught upon (there may be two of the three pins each caught on a bump), then I'd get out my color-coordinated Crayon and add a little paraffin to the offending bump and pin.  It wouldn't hurt to put a bit of paraffin on each of the bumps and each of the pins.  And then back off the Allen screw and leather plug and give the Minute Hand a spin like I show in the attached video.

 

Please keep me posted.  Let me know what you discover and what you did to fix this puzzle. 

Aloha.  Clayton