Re: Timing data for Synchronome # 2177

Neville Michie

It is quite clear from various set up instructions and clock
theory that if the pendulum is stationary, the roller should be half way down the slope.
This is how you set the suspension spring at the top.
In operation the arm is dropped before the zero crossing and lands on the flat,
then as it rolls down the slope the impulse is given with its centre of the impulse
being delivered on the zero crossing.
Neville Michie

On 25 Oct 2019, at 08:08, neil <> wrote:

Ive been following this with interest.
SO - I assume the roller should land on the flat, not the curved surface, and be timed so that:
the instant the roller starts to move down the face is at BDC of the pendulum. ??
Thats going to be hard to measure and even harder to achieve if 1/2mm is critical as Bepi suggests.

Neil Jepsen. B.Sc. M.Sc(Hons).CPL.MASNZ.
Jepsen Acoustics & Electronics Ltd
22 Domain Street
Palmerston North.
New Zealand.
Ph +64 6 3577539 Mob 0274428094
Web site:

E.& O.E.

On 25/10/2019 09:37 AM, Ian Richardson via Groups.Io wrote:

That is a detail in the setting up of Chris' clock. It shouldn't land on the curve but, according to F H-J, it should land on the shoulder just before the curve - even maybe a bit earlier on the flat part.

I think that too much emphasis is placed on the design of the impulse pallet - clearly the Synchronome type and the Gent type both work and both have a latitude for setting up error. Think about the Shortt Free Pendulum impulse - that consists of a flat faced jewel landing on a small wheel and it gives a very smooth impulse. There is more than one way to skin a cat!

Ian R

-----Original Message-----
From: Harvey Moseley <>
To: synchronome1 <>
Sent: Thu, 24 Oct 2019 22:22
Subject: Re: [synchronomeelectricclock] Timing data for Synchronome # 2177

Looks like it makes initial contact with the pallet on the curved surface. Is that correct?

On Oct 24, 2019, at 4:05 PM, Ian Richardson via Groups.Io <> wrote:

Thanks Chris. Perfect. End of discussion!!

Ian R

-----Original Message-----
From: Chris <>
To: synchronome1 <>
Sent: Thu, 24 Oct 2019 17:14
Subject: Re: [synchronomeelectricclock] Timing data for Synchronome # 2177

My now 10 year old YT video of the Synchronome has a short slow motion section:
Where the roller is lifted from the pallet before it falls off the end.

On 24/10/2019 16:59, Ian Richardson via Groups.Io wrote:
I refer to my earlier comment about the Pulsynetic. In that case, the roller clearly is lifted off the impulse surface by the resetting magnet. In the case of the Synchronome, I would doubt very much if the roller ever reaches (and falls off) the curved section of the pallet. Holding the pendulum and moving it to the left with the gravity arm roller on the pallet proves that the contact makes before the end of the travel on the pallet. However, under dynamic conditions it may be different - a high speed video of a Synchronome in action would verify this.

The comment about "the full weight of the gravity arm" aiding contact pressure is spurious because once contact has been made, ALL the effort of resetting the gravity arm goes through the contact. That is one if its main selling points.

Ian R
Macclesfield, UK

-----Original Message-----
From: Harvey Moseley <>
To: synchronome1 <>
Sent: Thu, 24 Oct 2019 16:28
Subject: Re: [synchronomeelectricclock] Timing data for Synchronome # 2177

It would seem to me that as it rolls off the edge of the pallet, it would provide a lateral impulse that would be undesirable.

On Oct 24, 2019, at 10:06 AM, Eric Scace <> wrote:
The roller is intended to roll off the pallet. That brings the full weight of the gravity arm into the contact closure, in order to have a more reliable contact closure.

On 2019 Oct 24, at 09:25 , Harvey Moseley <> wrote:

Hi John,
Thanks for the excellent comments. Does the roller fall off the pallet before the electrical contact is made to lift the gravity arm, or while the roller is on the pallet? It seems that this is an area of possible trouble as well.


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