• Important Executive Director Announcement from the NAWCC

    The NAWCC Board of Directors is pleased to announce that Mr. Rory McEvoy has been named Executive Director of the NAWCC. Rory is an internationally renowned horological scholar and comes to the NAWCC with strong credentials that solidly align with our education, fundraising, and membership growth objectives. He has a postgraduate degree in the conservation and restoration of antique clocks from West Dean College, and throughout his career, he has had the opportunity to handle some of the world’s most important horological artifacts, including longitude timekeepers by Harrison, Kendall, and Mudge.

    Rory formerly worked as Curator of Horology at the Royal Observatory, Greenwich, where his role included day-to-day management of research and digitization projects, writing, public speaking, conservation, convening conferences, exhibition work, and development of acquisition/disposal and collection care policies. In addition, he has worked as a horological specialist at Bonhams in London, where he cataloged and handled many rare timepieces and built important relationships with collectors, buyers, and sellers. Most recently, Rory has used his talents to share his love of horology at the university level by teaching horological theory, history, and the practical repair and making of clocks and watches at Birmingham City University.

    Rory is a British citizen and currently resides in the UK. Pre-COVID-19, Rory and his wife, Kaai, visited HQ in Columbia, Pennsylvania, where they met with staff, spent time in the Museum and Library & Research Center, and toured the area. Rory and Kaai will be relocating to the area as soon as the immigration challenges and travel restrictions due to COVID-19 permit.

    Some of you may already be familiar with Rory as he is also a well-known author and lecturer. His recent publications include the book Harrison Decoded: Towards a Perfect Pendulum Clock, which he edited with Jonathan Betts, and the article “George Graham and the Orrery” in the journal Nuncius.

    Until Rory’s relocation to the United States is complete, he will be working closely with an on-boarding team assembled by the NAWCC Board of Directors to introduce him to the opportunities and challenges before us and to ensure a smooth transition. Rory will be participating in strategic and financial planning immediately, which will allow him to hit the ground running when he arrives in Columbia

    You can read more about Rory McEvoy and this exciting announcement in the upcoming March/April issue of the Watch & Clock Bulletin.

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New Haven Calendar clock

1940century

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I have a New Haven Calendar clock, the calendar barrel or canon spins freely on the hour barrel. I'm not seeing what keeps the hand in place once the pin on the adjacent gear is away from the calendar gear teeth?

Hope that makes sense?

Mike
 

bikerclockguy

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There should be a pawl that mounts on the plate, and meshes with the teeth on the calendar cannon that will only let it advance one tooth in a 24-hour cycle. Timesavers sells a kit that includes the ratcheting pawl. I just recently finished a Sessions calendar clock that was missing that and some other parts as well. See my post under “Sessions Store Regulator/calendar clock missing parts, and there will be some helpful info/pics there that will help you figure it out. I know yours is a New Haven, but they are all similar.
 

Steven Thornberry

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I have a New Haven Calendar clock, the calendar barrel or canon spins freely on the hour barrel. I'm not seeing what keeps the hand in place once the pin on the adjacent gear is away from the calendar gear teeth?

Hope that makes sense?

Mike
Why not show us a picture of the movement to supplement your description?
 

Kevin W.

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You mean the pawl, lol. Well done.
 

bikerclockguy

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Just remembered something I encountered on mine. You should have a concave washer that fits snugly over the minute hand arbor. This will keep the calendar canon from climbing when it engages with the pin and feels resistance from the pawl. I accidentally left mine off on reassembly, and the calendar was jumping 8-10 days at a time. Took me a while to figure it out, but then I looked in my project box where I was keeping all the small parts, and spotted it in a corner. As soon as I saw it the light bulb came on, but had me scratching my head for a few hours.
 

1940century

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Just remembered something I encountered on mine. You should have a concave washer that fits snugly over the minute hand arbor. This will keep the calendar canon from climbing when it engages with the pin and feels resistance from the pawl. I accidentally left mine off on reassembly, and the calendar was jumping 8-10 days at a time. Took me a while to figure it out, but then I looked in my project box where I was keeping all the small parts, and spotted it in a corner. As soon as I saw it the light bulb came on, but had me scratching my head for a few hours.
Just remembered something I encountered on mine. You should have a concave washer that fits snugly over the minute hand arbor. This will keep the calendar canon from climbing when it engages with the pin and feels resistance from the pawl. I accidentally left mine off on reassembly, and the calendar was jumping 8-10 days at a time. Took me a while to figure it out, but then I looked in my project box where I was keeping all the small parts, and spotted it in a corner. As soon as I saw it the light bulb came on, but had me scratching my head for a few hours.
Thanks for that info,
I did not see a concave washer, and I do notice that it adds a day for the calendar, that is it jumps ahead?
I will have to come up with that washer.

Mike
 

bikerclockguy

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Thanks for that info,
I did not see a concave washer, and I do notice that it adds a day for the calendar, that is it jumps ahead?
I will have to come up with that washer.

Mike
What was happening with mine was that when the pin engaged the tooth on the calendar cannon and met some resistance from the pawl, the calendar hand would climb up above the pawl and pin, and then drop back down several days ahead. On my Sessions, the calendar cannon is a fairly loose fit, but the washer holds it in place and keeps it from climbing.
 

1940century

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Actually as I have been watching the date hand, it moves 2 days ahead? Not sure if it has something to do with the hand on the cannon or barrel in relation to the pin. But it has been doing this every day since i got the clock working?
 

shutterbug

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In your photo, the spring that should hold the wheel in place is under the wheel. It needs to be resting between the teeth, so when the wheel moves, it only allows one tooth to advance. When you get that fixed, if it still moves two teeth, the pin is positioned wrong.
 

Ralph

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FWIW, I’d call it a detent, instead of a pawl.

IMHO, Ralph
 

1940century

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Thanks,

That is what I Found was wrong in the earlier thread. I realized the pawl was pushed behind the wheel. Now that is corrected it moves the date twice, but not at the same time, so I assume that the pin needs to be positioned correctly?
 

bikerclockguy

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FWIW, I’d call it a detent, instead of a pawl.

IMHO, Ralph
 

shutterbug

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The pin should only engage once a day. If it's coming in contact twice a day, then the gear ratio is wrong. But if it's engaging once a day but moving the calendar wheel too far, it's the pin position that's wrong. Be sure the pin is straight too.
 

Rod Schaffter

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That is what I Found was wrong in the earlier thread. I realized the pawl was pushed behind the wheel. Now that is corrected it moves the date twice, but not at the same time, so I assume that the pin needs to be positioned correctly?
You might try bending the detent spring slightly towards the wheel to provide more tension...
 

Ralph

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Yes, pawls are used to control direction or drive a cog/rack. That is not what the calendar spring (detent) is doing. It is holding the date wheel in position. The date wheel/hand can be moved to any position desired and will detent in any of those positions.

Definition of DETENT

pawl - Google Search

Ralph
 
Last edited:

bikerclockguy

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You might try bending the detent spring slightly towards the wheel to provide more tension...
I had to fiddle with mine quite a bit, adjusting the mesh of the pawl with the teeth in and out to get it just right. Took me a half dozen tries or so. You will eventually find the right setting.
 

1940century

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I'm getting closer, now it moves 1 1/2 days on the calendar hand. I'm thinking the gear is not meshing correctly. Think the pin is not mid point on the calendar gear?

Looks like I will need to fiddle a bit more to get it right?
 

bikerclockguy

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I'm getting closer, now it moves 1 1/2 days on the calendar hand. I'm thinking the gear is not meshing correctly. Think the pin is not mid point on the calendar gear?

Looks like I will need to fiddle a bit more to get it right?
If it’s like my Sessions, you won’t be able to get it to line up perfectly for every day of the month. On mine, there’s quite a bit of wiggle on the hour cannon, and gravity has its way. I finally settled for having the hand line up perfectly on the “downstroke dates”(between 12:00 and 6:00). It lands little past the halfway point on the “upstroke dates”(between 7:00 and 12:00), so you have to round up on those. If anyone has a good suggestion for tightening up the action, I’d like to know the trick as well.
 

shutterbug

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On yours, I think you want the pin to engage the wheel more toward the points rather than deeper. Then it won't try to turn it so far.
 

bikerclockguy

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On yours, I think you want the pin to engage the wheel more toward the points rather than deeper. Then it won't try to turn it so far.
SB, I assume you were talking about 1940’s clock? On mine, the depth of the ratcheting pawl is adjustable, but the wheel the advancing pin is on is mounted on a solid arbor.
 

Willie X

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Generally, the pin carries the 31 tooth dedent wheel forawd to a certain point, at this point the pressure from the decent spring takes over and gingerly snaps the wheel forward one day. The pin has to be positioned so that it is not bumped when this sudden shift happened. The position and shape of the sharp bends in the active end and dedent spring often have to be modified to make this a happen correctly. Not much different from a common moon dial operation Willie X
 

1940century

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I can see that the pin and wheel tooth position need to be in a position that it encounters the tooth at just below the tip of the tooth above the pin, so It won't let the wheel/detent past so as to go further than just the one day? Hope that make sense.

I think I may have achieved this position as it so far is only moving the date hand one day per day?
 

shutterbug

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Good. That sounds hopeful :)
 
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