Elegent Scroll Frame Skeleton Clock

[crueby]

I agree - that difference in weight is negligable. The weight CAN be important, since it will effect how much the pallet can impart, and the extra arc will change how the pallet acts and the period.

The hanger spring can be a bigger effect. A different strength/flexibility there will change things a lot - too stiff a spring can cause the issues you are seeing - you want the pendulum to swing freely and not be held back by the spring, some clocks used a fixed triangular pivot rather than a spring. I have had problems on my clocks with too stiff a hanger spring, going to a thinner/more flexible spring solved them. I think it would be worth getting some spring to the proper spec and trying it. Timesavers.com carries a range of the spring material.

[Kim]

Thanks for the pointer to Timesavers, Chris.  I've bought some stuff from them, but didn't realize they had the spring steel for the pendulum!  They have a lot of stuff there, but it isn't always easy to find (at least for me - probably because I don't know the correct terminology to search for  ) ).

My current run is past 19 hours and still going.  However, I think I'll be stopping it because I have decided I want to make a new set of pallets.  I believe that I can make the pallets a little longer.  This should let me bring the adjustable bush back closer to the nominal position.   When the adjustable bush is too far off center, it causes the pallet arbor to bind.  I've opened the pivot hole up quite a bit, which has helped.  But I'm running right on the edge.  I turn the bush to where the pallet arbor just starts to show a little friction, then back off a little.  And that is seeming to work.  But I would like a little more margin.  I think I can do that by redoing the pallets and making them a little deeper.

I may go with a different spring after this.  But I'm still going to remake the escapement.

Kim

[crueby]

Great that its running better!

For the pallet height, is it possible to put another copy of the adjustable bush on the other frame too? To let you raise lower it level-ly? (not a word till now, I think!    )

[Kim]

Yet another very good idea!

Unfortunately, I don't think there is.   The pivot for the pallet arbor is quite close to the pendulum post on the backcock.  For it to work right, the adjustable bush would have to be the same size in the front and back.  And there isn't room for that in the back.


But that's a great out-of-the-box idea!

Kim

[crueby]

They keep trying to stuff me back in the box (to return me?) but I keep climbing back out...




Another option - oval the holes in the back cock plat to raise or lower it to level the pivot? 

[kvom]

For the Strutt clock Smith specifies a feeler gauge for the spring.  You could get a set with different thicknesses inexpensively.

[Kim]

That's a great idea, kvom!  I've got feeler gauges that I use for shimming things.  I've found them very useful. I'm sure I could spare one to use as a spring, if I decide to try something different.

Kim

[Kim]

To remake the pallets, cut a piece of W-1 and reamed a 3/32” hole where the arbor should go (well, two holes, but only one was in the right place! )  then traced the shape of my current mostly working anchor onto the blank as a starting point.


After some rough cutting, some filing and testing, and more filing and testing, I came up with this – the top one is the new one.


While they look pretty much the same, when you set them on top of each other, you can see they actually ARE different.  The left pallet is a smidge longer, but the right one is significantly longer.  I'd pictured making them both longer/deeper, but that isn't really how it worked out.


While I had the clock apart to do this, I decided it was time to do something about the maintaining spring.  That spring bent out of shape under the force of the barrel & fusee the first time I wound the clock.  It was clear that the spring needed to be a bit stronger.  So, I decided to harden it, then temper it so that it would still work like a spring.  I clearly didn’t do a very good job of tempering.  It snapped almost immediately (bottom left part(s) in the pic).  The spring ran tight up against the hub, so only the tail provided the springiness.  But it just bent.   So for my next attempt at a spring (on the right), I made it with a bigger radius around the middle hub so that the spring has more length to ‘spring’ with.  This looks like it’s working now. It isn’t bending immediately under load at least!  Time will tell…


After reassembling everything and getting the new escapement tuned, the adjustable bush is now only about 20-30 degrees.  That’s way less than before.  So I gained some margin here, which is what I was after.


Things seem to be running freely, and the clock is now ticking away.   I moved it off of my main bench so that I can keep working on things, but leave it running.  Hopefully for several days!  You can see my nanny-cam set on a box there.  That way, I can check the clock without having to go out to the shop.


I also put some tape on the center arbor as a ‘minute hand’, and another piece of tape on the fusee stop.  It turns out that the ratio between the Fusee and the center arbor is 12:1. How convenient is that?  So the tape on the fusee stop is kinda like an hour hand, but it runs backwards.    And it’s hard to see because it’s behind the front frame.


You can also see I wound it up all the way so that I’m set for a full 7-day run! (He says optimistically.)  I’m already up to 90 minutes! 

I plan to make the maintaining click next.
Kim

[crueby]

Tickity tickity tockity...   

[bent]

..the mice run up the clockety...

Following along, Kim.  Hope the new pallet works the way you wanted it too...

[Kim]

Thanks, Chris and Bent!

We're at 31 hours and going strong!  So that's good 

I'm going for an endurance record here.  I'm going to run it till it fully unwinds.  John Wilding designed it to be a 7-day clock.  I think I will get about 8 days from it, based on my calculations.  It's limited by the number of turns of cable you can get on the fusee.  The fusee is 1.5" long, and the groove is 12 TPI.  So that would be 18 threads. But you don't get the full thread on either end, so I'm saying 16 threads.  The fusee will make 2 complete turns in a 24-hour period, so 8 days.  It could be a little more or a less than that.  But as long as I get more than 7 days, I'll be happy.  That way I can wind it once a week.  That's my goal!

I just hope it keeps doing the tickety-tockity thing the whole time! 

Kim

[crueby]

Excellent!!

[bent]

That's sounding tickety-boo Kim!   

[cnr6400]

  Congrats on the 31 + hr run Kim! Great news. 

[vtsteam]

Fingers crossed, Kim, that it continues for 8 days!