Date   

Re: Count wheel & backstop roller & Pendulum length to bob?

Chris Wollaston
 

Hi, well, I may be in a bit of a pickle here with this pendulum and bob. The facts are:
Bob weight = 9.25lbs, dimensions of bob: Ht = 15.4cm,  Dia = 6.2 cm
Invar steel rod length - w/o threaded adjuster, just rod to steel top clamp, not with suspension spring = 102cm
So, is it likely that the CofG is going to be very much different to a 16lb bob on a standard Invar rod of say 108cm that an acquaintance has on a Synchronome master and hence the time period for each swing way out of standardisation?
i.e. Is it likely that this pendulum and bob are for a different clock altogether?
If it isn't going to keep anywhere like correct time then how do I source the correct pendulum and bob?


Re: Count wheel & backstop roller & Pendulum length to bob?

John Hubert
 

I have just had an (approximate) as they are running measure.

Clock No 1 - Lead bob about 16 lbs I believe - fitted with light early type weight tray.  Approx 90 cm from top of lower brass suspension block to top of bob
Clock No 2 -Steel bob - 16 lbs nominal - fitted with heavier pattern weight tray and seconds trip.  Again approx 90 cm from top of lower brass suspension block to top of bob

Both these clocks are running.

I can’t remember what the thread should be - but 8 BA is too small.  Mine is 4BA (about 3.5mm outside diameter) and the threaded section is approx 65mm with about 12mm unthreaded and reduced diameter unthreaded at the bottom.  These thread into the invar rod which has a female thread.  The bob should be nominally about 16 lbs.  On looking at a ’spare’ rod, there is no notch/mark.  

John

On 23 Feb 2021, at 14:43, Chris Wollaston <chris@...> wrote:

Hi John, Many tks for the info on various bobs and pendulum lengths. My pendulum doesn't have a weights tray and sadly, someone must have dropped the pendulum and snapped off a length of the 8BA? threaded end on which the brass rating nut travels. Thus, I've 41mm of thread sticking out the bottom of the rod but no record of how long it should be when intact?  The cylindrical brass bob weighs 4.4kg approx 9.25lbs and looks authentic so a very rough measurement guide from the top of the brass block above the suspension spring to the top of the bob would be a useful start? I'm suggesting 92cm, what do you reckon? Chris


Re: Count wheel & backstop roller & Pendulum length to bob?

Chris Wollaston
 

Correction, the bob weighs 4.2kg


Re: Count wheel & backstop roller & Pendulum length to bob?

Chris Wollaston
 

Hi John, Many tks for the info on various bobs and pendulum lengths. My pendulum doesn't have a weights tray and sadly, someone must have dropped the pendulum and snapped off a length of the 8BA? threaded end on which the brass rating nut travels. Thus, I've 41mm of thread sticking out the bottom of the rod but no record of how long it should be when intact?  The cylindrical brass bob weighs 4.4kg approx 9.25lbs and looks authentic so a very rough measurement guide from the top of the brass block above the suspension spring to the top of the bob would be a useful start? I'm suggesting 92cm, what do you reckon? Chris


Re: Count wheel & backstop roller & Pendulum length to bob?

John Hubert
 

The ‘notch’ is really a little file cut - and I don’t think it was always used, but I have seen it on some of my clocks.  It was not very accurate because things varied.  A variety of bob shapes and variations have been used; normal and shell type (at least two versions of shell type), iron/steel, lead, brass, possible other combinations (I have heard suggested brass case, lead fill).  In addition - various other ‘additions’ are occasionally used on the rod; weight trays are common, seconds switch ’trip’ is used on seconds clocks, synchroniser spring assembly is used on a few clocks etc, so it is only a very approximate mark for initial set up.  If you start by putting the rating nut about half way up the available thread, you will soon find you can work from there.  As you get close - you have to take more time, but the initial ‘coarse’ adjustment can be done simply by comparison with a seconds equipped radio controlled clock and typical can be got within a minute a day or so quite easily.  More patience is needed for the fine adjustment!  Very fine ’trimming’ can be achieved by a 4 or 6 BA washer (or two) on the bob top.

John

On 23 Feb 2021, at 13:36, Chris Wollaston <chris@...> wrote:

Hi, I've just fitted my backstop glass roller but it persisted in remaining in front of the Y-bracket thus not held in place and at risk of falling off and disappearing under the furniture (for a second time) so I've bent the backstop wire hopefully sufficiently to tuck one edge of the roller just behind the bracket. The next task is to get the count-wheel vane just a few thou from the latch as per the picture in Bob Miles' tome, p.238, because at the mo it's some way off.
Also, I read somewhere, either tvtesla or the manual that the pendulum's Invar steel rod is supposed to have a 'notch' showing where the top of the bob should be placed. Mine has no notch, just some oxidation roughly in the right place so can anyone give me a measurement from the top of the trunnion's upper brass block to top of bob please? Tks, Chris in E Sussex


Re: Count wheel & backstop roller & Pendulum length to bob?

Chris Wollaston
 

Hi, I've just fitted my backstop glass roller but it persisted in remaining in front of the Y-bracket thus not held in place and at risk of falling off and disappearing under the furniture (for a second time) so I've bent the backstop wire hopefully sufficiently to tuck one edge of the roller just behind the bracket. The next task is to get the count-wheel vane just a few thou from the latch as per the picture in Bob Miles' tome, p.238, because at the mo it's some way off.
Also, I read somewhere, either tvtesla or the manual that the pendulum's Invar steel rod is supposed to have a 'notch' showing where the top of the bob should be placed. Mine has no notch, just some oxidation roughly in the right place so can anyone give me a measurement from the top of the trunnion's upper brass block to top of bob please? Tks, Chris in E Sussex


Re: Count wheel & backstop roller

Andrew Nahum
 

In mine there is a c shaped clip or circlip that retains the roller. Is there a groove around the wire you can see under a glass? 


On Mon, Feb 22, 2021 at 3:41 PM Chris Wollaston <chris@...> wrote:
Dear All, I've just joined the forum and in the process of setting up my 1920s Synchronome master (Serial 1152) in mahogany case and have carefully dismounted the Y-shaped brass bracket that holds the count wheel and latch because the pivot pins were bent and the wheel gummed up with old sticky oil.  Now cleaned and straightened I'm poised to re-assemble but see that I've been supplied with either a wee glass or solid alloy roller bead to fit on the backstop wire.  However, there doesn't seem to be a way of preventing the bead falling off the wire so is it just held in place by the brass Y or should I drop a spot of glue on the end to prevent it falling off? Bests, Chris in E Sussex


Re: Synchronome contacts pitted

James Kelly
 

Hi all

An eBay search for either glass cylinder bead or glass tube bead brings up a vast array of glass beads some of which may be suitable as a roller 

Jim


On 22 Feb 2021, at 18:40, Ian Richardson via groups.io <irichar361@...> wrote:


If you can find some, glass capillary tubing will do the trick.  I made one a few years ago, but I've no idea where the glass tube is now!

Failing that, a piece of silver steel of the correct diameter can easily be drilled.  It could then be made dead hard by heating it red hot and quenching in cold water.  It should then be polished - I made a gathering "jewel" this way a few years ago as a temporary measure, and it's still there doing a good job.

Otherwise, I agree with everything John said about adjustment and running dry.  The effective weight of the glass roller can be varied by winding fine wire around the counterbalancing arm.

Good luck, and welcome to the club!

Ian R
France



-----Original Message-----
From: Andrew Nahum <andrew.nahum@...>
To: synchronome1@groups.io
Sent: Mon, 22 Feb 2021 19:16
Subject: Re: [synchronomeelectricclock] Synchronome contacts pitted


 A supply for the glass rollers for the ‘back stop’ or detent that runs on the count wheel would be great. Has anyone any news on a source for them?  I think I recall Jan Wright produced some a few years ago and they all sold out like hot cakes. I am currently using a delrin one kindly made by a friend but I fancy glass would have the lowest friction in that application. 

Andrew 


On 18 Feb 2021, at 20:46, Stephen Hibbs <oldtimemachines@...> wrote:

 Hi, Naing,

There are reproduction gathering arms for sale right now on eBay for 25 US dollars plus a nominal shipping cost. Just enter the search term “Synchronome”. Making one would be an interesting challenge, but if you want one right now, here you go.

Stephen Hibbs
PO Box 536
Markleeville, CA 96120
530-694-1045




On Feb 18, 2021, at 12:19 PM, bailey.services via groups.io <bailey.services@...> wrote:

Hi pallet design drawing is on NAWCC clock forum website dated 17 sept 2007 posted by fdew


Re: Synchronome contacts pitted

Ian Richardson
 

If you can find some, glass capillary tubing will do the trick.  I made one a few years ago, but I've no idea where the glass tube is now!

Failing that, a piece of silver steel of the correct diameter can easily be drilled.  It could then be made dead hard by heating it red hot and quenching in cold water.  It should then be polished - I made a gathering "jewel" this way a few years ago as a temporary measure, and it's still there doing a good job.

Otherwise, I agree with everything John said about adjustment and running dry.  The effective weight of the glass roller can be varied by winding fine wire around the counterbalancing arm.

Good luck, and welcome to the club!

Ian R
France



-----Original Message-----
From: Andrew Nahum <andrew.nahum@...>
To: synchronome1@groups.io
Sent: Mon, 22 Feb 2021 19:16
Subject: Re: [synchronomeelectricclock] Synchronome contacts pitted


 A supply for the glass rollers for the ‘back stop’ or detent that runs on the count wheel would be great. Has anyone any news on a source for them?  I think I recall Jan Wright produced some a few years ago and they all sold out like hot cakes. I am currently using a delrin one kindly made by a friend but I fancy glass would have the lowest friction in that application. 

Andrew 


On 18 Feb 2021, at 20:46, Stephen Hibbs <oldtimemachines@...> wrote:

 Hi, Naing,

There are reproduction gathering arms for sale right now on eBay for 25 US dollars plus a nominal shipping cost. Just enter the search term “Synchronome”. Making one would be an interesting challenge, but if you want one right now, here you go.

Stephen Hibbs
PO Box 536
Markleeville, CA 96120
530-694-1045




On Feb 18, 2021, at 12:19 PM, bailey.services via groups.io <bailey.services@...> wrote:

Hi pallet design drawing is on NAWCC clock forum website dated 17 sept 2007 posted by fdew


Re: Synchronome contacts pitted

John Hubert
 

Perspex works well and is easy to work.  It also looks almost indistinguishable from glass.  You can buy a rod of perspex very reasonably and make the rollers in a small lathe.  Glass is more difficult, but can be done.  I have not seen any for sale.

On 22 Feb 2021, at 18:16, Andrew Nahum <andrew.nahum@...> wrote:


A supply for the glass rollers for the ‘back stop’ or detent that runs on the count wheel would be great. Has anyone any news on a source for them?  I think I recall Jan Wright produced some a few years ago and they all sold out like hot cakes. I am currently using a delrin one kindly made by a friend but I fancy glass would have the lowest friction in that application. 

Andrew 


On 18 Feb 2021, at 20:46, Stephen Hibbs <oldtimemachines@...> wrote:

Hi, Naing,

There are reproduction gathering arms for sale right now on eBay for 25 US dollars plus a nominal shipping cost. Just enter the search term “Synchronome”. Making one would be an interesting challenge, but if you want one right now, here you go.

Stephen Hibbs
PO Box 536
Markleeville, CA 96120
530-694-1045




On Feb 18, 2021, at 12:19 PM, bailey.services via groups.io <bailey.services@...> wrote:

Hi pallet design drawing is on NAWCC clock forum website dated 17 sept 2007 posted by fdew



Re: Synchronome contacts pitted

Andrew Nahum
 


A supply for the glass rollers for the ‘back stop’ or detent that runs on the count wheel would be great. Has anyone any news on a source for them?  I think I recall Jan Wright produced some a few years ago and they all sold out like hot cakes. I am currently using a delrin one kindly made by a friend but I fancy glass would have the lowest friction in that application. 

Andrew 


On 18 Feb 2021, at 20:46, Stephen Hibbs <oldtimemachines@...> wrote:

Hi, Naing,

There are reproduction gathering arms for sale right now on eBay for 25 US dollars plus a nominal shipping cost. Just enter the search term “Synchronome”. Making one would be an interesting challenge, but if you want one right now, here you go.

Stephen Hibbs
PO Box 536
Markleeville, CA 96120
530-694-1045




On Feb 18, 2021, at 12:19 PM, bailey.services via groups.io <bailey.services@...> wrote:

Hi pallet design drawing is on NAWCC clock forum website dated 17 sept 2007 posted by fdew


Re: Count wheel & backstop roller

John Hubert
 

Glass is correct.  I have also used perspex (glass is relatively difficult to drill) with success.  The keys to the clock running well are that;

  1. The teeth of the count wheel are clean and dry (it runs with the teeth dry NOT oiled)
  2. The gathering jewel engages the teeth JUST enough to gather a tooth and allow the backstop roller to drop - not more.  Having the jewel set too low looses energy and the Synchronome is pretty ’tight’ on energy.
  3. The slope of the pallet down which the roller rolls must also be clean and dry - as must the surfaces of the roller itself.  It should drop just on the corner of the slope.

Bob's book should enable you to get it running fine.  The clock pictured has run well for many years for me without anything more than an occasional clean and keeps excellent time.

John

On 22 Feb 2021, at 16:07, Chris Wollaston <chris@...> wrote:

Hi John, many tks for that and excellent picture. I'm going to require a steady pair of hands to get it set up.  Any preference as to which bead to use, glass or alloy? The alloy one has a raised edge both sides.  Also, I've been avidly studying Bob Miles tome Ch 13 on setting up the pendulum and impulse pallet under the roller and am now awaiting a replacement suspension spring as the one that came with the clock is twice as long as the correct version shown on p.236 plus it has a crimp in the metal. This will be the next challenge. Chris


Re: Count wheel & backstop roller

Chris Wollaston
 

Hi John, many tks for that and excellent picture. I'm going to require a steady pair of hands to get it set up.  Any preference as to which bead to use, glass or alloy? The alloy one has a raised edge both sides.  Also, I've been avidly studying Bob Miles tome Ch 13 on setting up the pendulum and impulse pallet under the roller and am now awaiting a replacement suspension spring as the one that came with the clock is twice as long as the correct version shown on p.236 plus it has a crimp in the metal. This will be the next challenge. Chris


Re: Count wheel & backstop roller

John Hubert
 

In fact it cannot ‘fall off’ because the K shaped bridge is ‘in the way’.  Photo of a slightly earlier clock (which has been running for many years) attached.


John

On 22 Feb 2021, at 15:41, Chris Wollaston <chris@...> wrote:

Dear All, I've just joined the forum and in the process of setting up my 1920s Synchronome master (Serial 1152) in mahogany case and have carefully dismounted the Y-shaped brass bracket that holds the count wheel and latch because the pivot pins were bent and the wheel gummed up with old sticky oil.  Now cleaned and straightened I'm poised to re-assemble but see that I've been supplied with either a wee glass or solid alloy roller bead to fit on the backstop wire.  However, there doesn't seem to be a way of preventing the bead falling off the wire so is it just held in place by the brass Y or should I drop a spot of glue on the end to prevent it falling off? Bests, Chris in E Sussex


Count wheel & backstop roller

Chris Wollaston
 

Dear All, I've just joined the forum and in the process of setting up my 1920s Synchronome master (Serial 1152) in mahogany case and have carefully dismounted the Y-shaped brass bracket that holds the count wheel and latch because the pivot pins were bent and the wheel gummed up with old sticky oil.  Now cleaned and straightened I'm poised to re-assemble but see that I've been supplied with either a wee glass or solid alloy roller bead to fit on the backstop wire.  However, there doesn't seem to be a way of preventing the bead falling off the wire so is it just held in place by the brass Y or should I drop a spot of glue on the end to prevent it falling off? Bests, Chris in E Sussex


Re: Synchronome contacts pitted

John Hubert
 

If you search eBay - there is an un-machined impulse pallet casting listed in the UK.  (I am not and have no connection with the seller - nor have I ever seen or examined the part.)

John

On 20 Feb 2021, at 13:02, N Linn <naingtlin@...> wrote:

Dear Stephen,

Your advices are very much appreciated and giving me a lot to think about recreating a part to work with. That helps expanding the idea by various perspectives and thank you so much. 

It would be great if you can examine the picture provided by Norman. Let me send you the file attached.

Best wishes,
Naing

On Sat, Feb 20, 2021, 3:21 AM Stephen Hibbs <oldtimemachines@...> wrote:
Hi, Naing,

I can’t seem to get Norman’s .jpg to download. Wish I could see it. But as a mechanical engineer who has designed thousands of parts for manufacturing, I have some comments about the .pdf from bailey.services that might simplify its fabrication with no loss of functionality.

1. The curved ramp is shown as a segment of the developed surface of a toroid. Again, this could be simplified. If it was simply the surface of a cylinder instead, it could be generated by the simple motion of a milling cutter instead of a complex motion, if you follow me. The roller on the Synchronome’s gravity arm won’t know the difference if it is truly rolling instead of sliding (which it might do if its pivots aren’t sufficiently lubricated). There might be a very slight tendency to twist the pendulum if it rolls down either edge rather than the surface, but I think that would be negligible. If the correct suspension spring is used, it has considerable torsional stiffness and the pendulum bob has huge torsional inertia.
      And I still suspect a straight ramp is as good as a curved one. If I were making this part, I’d make the flat ramp long enough that the roller would land below the top of the ramp and be lifted off before reaching the bottom. This is what Gents’ does and it extracts all the potential energy available in the time the roller and pallet are in contact with each other.

2.  I believe the 45-degree facets are intended to act as elastic hinges where thin material embraces the pendulum rod. But they are so long that I’m not convinced that a single 4-40NC screw in brass will be able to generate adequate clamping force around the rod. And the effort to generate enough clamping force will likely strip the female thread, leaving you with no clamping force at all. The safe way out is two screws, though there is still risk of stripping one of the female threads if they are tightened unevenly.
     You’ll likely be starting with .50-inch thick stock, or maybe the nearest metric equivalent. There’s really no need to machine it down to .44 inch thick, nor is there a functional need to machine the two 45-degree facets on the end opposite the ramp; only an aesthetic one. Nor is there a need for the counterbore if those facets are omitted.

3.   The .035 dia. thru hole gives the gathering arm a place to be, but I don’t see what keeps it there unless the 2-56NC hole below it is part of a retaining scheme not shown. The original pallet part, of course, has an elegant but complex retaining scheme machined into it that was wisely avoided in this design.

4.   The .38 radius on the underside can actually be any radius that’s convenient. It does happen to match the specified radius of the ramp.

Kind regards,
Steve

Stephen Hibbs
PO Box 536
Markleeville, CA 96120
530-694-1045




On Feb 19, 2021, at 1:29 AM, Norman Heckenberg <heckenberg@...> wrote:

<pallet.jpg>




-- 
Naing<pallet.jpg>


Re: Synchronome contacts pitted

Stephen Hibbs
 

Hi, Naing,

Thanks for re-sending me Norman’s picture. It is very much more like the Synchronome original part. It differs only, as far as I can see, in the way it retains the gathering arm. The very thin wall embracing the pendulum rod makes for easy clamping with a small screw. This part would also be difficult to fabricate. The text further up the page isn’t visible, but I expect it mentions that making this part begins as a casting. Achieving that thin, circular outer shape would be difficult even by that method, almost impossible by any other. My other comments as to the importance of curves vs. straight lines, etc. would still apply to the making of this part. The dimensioning convention used here only alludes to the formation of the ramp as a section of the surface of a torus; it’s not explicit. That would be complex to set up for machining, someone one would only do if it was thought to be truly necessary (and I don’t think so), and was going to be made in quantity.

An additional comment about the other design:

5.   Unless I’m missing something, it would put the gathering arm off center. That is, it would miss the count wheel. Perhaps it’s intended to work with a gathering arm of a different design, one with a jog in it that puts the gathering jewel back on the centerline.

Best regards,
Steve

Stephen Hibbs
PO Box 536
Markleeville, CA 96120
530-694-1045




On Feb 20, 2021, at 5:02 AM, N Linn <naingtlin@...> wrote:

Dear Stephen,

Your advices are very much appreciated and giving me a lot to think about recreating a part to work with. That helps expanding the idea by various perspectives and thank you so much. 

It would be great if you can examine the picture provided by Norman. Let me send you the file attached.

Best wishes,
Naing

On Sat, Feb 20, 2021, 3:21 AM Stephen Hibbs <oldtimemachines@...> wrote:
Hi, Naing,

I can’t seem to get Norman’s .jpg to download. Wish I could see it. But as a mechanical engineer who has designed thousands of parts for manufacturing, I have some comments about the .pdf from bailey.services that might simplify its fabrication with no loss of functionality.

1. The curved ramp is shown as a segment of the developed surface of a toroid. Again, this could be simplified. If it was simply the surface of a cylinder instead, it could be generated by the simple motion of a milling cutter instead of a complex motion, if you follow me. The roller on the Synchronome’s gravity arm won’t know the difference if it is truly rolling instead of sliding (which it might do if its pivots aren’t sufficiently lubricated). There might be a very slight tendency to twist the pendulum if it rolls down either edge rather than the surface, but I think that would be negligible. If the correct suspension spring is used, it has considerable torsional stiffness and the pendulum bob has huge torsional inertia.
      And I still suspect a straight ramp is as good as a curved one. If I were making this part, I’d make the flat ramp long enough that the roller would land below the top of the ramp and be lifted off before reaching the bottom. This is what Gents’ does and it extracts all the potential energy available in the time the roller and pallet are in contact with each other.

2.  I believe the 45-degree facets are intended to act as elastic hinges where thin material embraces the pendulum rod. But they are so long that I’m not convinced that a single 4-40NC screw in brass will be able to generate adequate clamping force around the rod. And the effort to generate enough clamping force will likely strip the female thread, leaving you with no clamping force at all. The safe way out is two screws, though there is still risk of stripping one of the female threads if they are tightened unevenly.
     You’ll likely be starting with .50-inch thick stock, or maybe the nearest metric equivalent. There’s really no need to machine it down to .44 inch thick, nor is there a functional need to machine the two 45-degree facets on the end opposite the ramp; only an aesthetic one. Nor is there a need for the counterbore if those facets are omitted.

3.   The .035 dia. thru hole gives the gathering arm a place to be, but I don’t see what keeps it there unless the 2-56NC hole below it is part of a retaining scheme not shown. The original pallet part, of course, has an elegant but complex retaining scheme machined into it that was wisely avoided in this design.

4.   The .38 radius on the underside can actually be any radius that’s convenient. It does happen to match the specified radius of the ramp.

Kind regards,
Steve

Stephen Hibbs
PO Box 536
Markleeville, CA 96120
530-694-1045




On Feb 19, 2021, at 1:29 AM, Norman Heckenberg <heckenberg@...> wrote:

<pallet.jpg>




--
Naing <pallet.jpg>


Re: Synchronome contacts pitted

N Linn
 
Edited

Hi Neville,

Good to know you have those. I'm not sure which one would fit to my movement. Will you consider selling one for me? 

Best regards,
Naing


On Sat, Feb 20, 2021, 12:28 PM Neville Michie via groups.io <neville_michie=yahoo.com@groups.io> wrote:
Hi Naing,
I have an early Synchronome with an obscure history.
It has without doubt been made in the Synchronome factory,
but was probably sold as the movement alone. It has no serial number.
It has been fitted in a hardwood case with bevelled glass.
The latch dates the unit as quite early, about 1917 is my best guess.
The point of interest here is that the pallet design was different.
I am attaching photos of the original pallet with a set screw and 
another pallet with a clamp fixing. The setscrew model was on the 
unit when I got it.
cheers, 
Neville Michie


On 20 Feb 2021, at 08:02, Odell, Edward via groups.io <edward.odell=kcl.ac.uk@groups.io> wrote:

Hi Naing, 
 
In the picture you sent with your first post, the movement that you have looks to be an interesting and early example. It does not have an overthrow damper for the gravity arm and it has the early type of latch. These early clocks did not have the later standardised impulse pallet, they had a much shorter curve which was less efficient. It probably does not matter exactly which curve you make for your clock so long as the contacts close before the roller reaches the end of the curve.
However, it would be interesting to know the serial number of your clock. This is stamped into the bottom of the NRA plate. I can make out a 0 in the number but I cannot see the exact number. If the number is very low this could be an interesting movement historically and it would be good if you could let us know the serial number. We might then be able to tell you which design of impulse pallet match the date of your clock
 
Eddy Odell 
 
From: synchronome1@groups.io <synchronome1@groups.io> On Behalf Of Stephen Hibbs via groups.io
Sent: 19 February 2021 20:51
To: synchronome1@groups.io
Subject: Re: [synchronomeelectricclock] Synchronome contacts pitted
 
Hi, Naing,
 
I can’t seem to get Norman’s .jpg to download. Wish I could see it. But as a mechanical engineer who has designed thousands of parts for manufacturing, I have some comments about the .pdf from bailey.services that might simplify its fabrication with no loss of functionality.
 
1. The curved ramp is shown as a segment of the developed surface of a toroid. Again, this could be simplified. If it was simply the surface of a cylinder instead, it could be generated by the simple motion of a milling cutter instead of a complex motion, if you follow me. The roller on the Synchronome’s gravity arm won’t know the difference if it is truly rolling instead of sliding (which it might do if its pivots aren’t sufficiently lubricated). There might be a very slight tendency to twist the pendulum if it rolls down either edge rather than the surface, but I think that would be negligible. If the correct suspension spring is used, it has considerable torsional stiffness and the pendulum bob has huge torsional inertia.
      And I still suspect a straight ramp is as good as a curved one. If I were making this part, I’d make the flat ramp long enough that the roller would land below the top of the ramp and be lifted off before reaching the bottom. This is what Gents’ does and it extracts all the potential energy available in the time the roller and pallet are in contact with each other.
 
2.  I believe the 45-degree facets are intended to act as elastic hinges where thin material embraces the pendulum rod. But they are so long that I’m not convinced that a single 4-40NC screw in brass will be able to generate adequate clamping force around the rod. And the effort to generate enough clamping force will likely strip the female thread, leaving you with no clamping force at all. The safe way out is two screws, though there is still risk of stripping one of the female threads if they are tightened unevenly.
     You’ll likely be starting with .50-inch thick stock, or maybe the nearest metric equivalent. There’s really no need to machine it down to .44 inch thick, nor is there a functional need to machine the two 45-degree facets on the end opposite the ramp; only an aesthetic one. Nor is there a need for the counterbore if those facets are omitted.
 
3.   The .035 dia. thru hole gives the gathering arm a place to be, but I don’t see what keeps it there unless the 2-56NC hole below it is part of a retaining scheme not shown. The original pallet part, of course, has an elegant but complex retaining scheme machined into it that was wisely avoided in this design.
 
4.   The .38 radius on the underside can actually be any radius that’s convenient. It does happen to match the specified radius of the ramp.
 
Kind regards,
Steve
 
Stephen Hibbs
PO Box 536
Markleeville, CA 96120
530-694-1045
oldtimemachines@...
 
 



On Feb 19, 2021, at 1:29 AM, Norman Heckenberg <heckenberg@...> wrote:
 
<pallet.jpg>
 


--
Naing


Re: Synchronome contacts pitted

John Hubert
 

For your information, clock 707 would date to about 1919 and would (probably) have originally been in a 'false pediment’ type case, found (mainly) between the approximate serial number range of 680 (around 1918/9) and 900 (1922).  I say approximate, because there is no exact transition with some overlapping of the case styles.  It is therefore over 100 years old.

John

On 20 Feb 2021, at 13:06, N Linn <naingtlin@...> wrote:

Hi Eddy,

Thanks for the message.  The serial no. reads 707. Kindly see in attach for your reference. I'm not very well understand about these parts. But i saw some videos on youtube similar to this clock. 

Best regards,
Naing

On Sat, Feb 20, 2021, 3:32 AM Odell, Edward via groups.io <edward.odell=kcl.ac.uk@groups.io> wrote:

Hi Naing,

 

In the picture you sent with your first post, the movement that you have looks to be an interesting and early example. It does not have an overthrow damper for the gravity arm and it has the early type of latch. These early clocks did not have the later standardised impulse pallet, they had a much shorter curve which was less efficient. It probably does not matter exactly which curve you make for your clock so long as the contacts close before the roller reaches the end of the curve.

However, it would be interesting to know the serial number of your clock. This is stamped into the bottom of the NRA plate. I can make out a 0 in the number but I cannot see the exact number. If the number is very low this could be an interesting movement historically and it would be good if you could let us know the serial number. We might then be able to tell you which design of impulse pallet match the date of your clock

 

Eddy Odell

 

From: synchronome1@groups.io <synchronome1@groups.io> On Behalf Of Stephen Hibbs via groups.io
Sent: 19 February 2021 20:51
To: synchronome1@groups.io
Subject: Re: [synchronomeelectricclock] Synchronome contacts pitted

 

Hi, Naing,

 

I can’t seem to get Norman’s .jpg to download. Wish I could see it. But as a mechanical engineer who has designed thousands of parts for manufacturing, I have some comments about the .pdf from bailey.services that might simplify its fabrication with no loss of functionality.

 

1. The curved ramp is shown as a segment of the developed surface of a toroid. Again, this could be simplified. If it was simply the surface of a cylinder instead, it could be generated by the simple motion of a milling cutter instead of a complex motion, if you follow me. The roller on the Synchronome’s gravity arm won’t know the difference if it is truly rolling instead of sliding (which it might do if its pivots aren’t sufficiently lubricated). There might be a very slight tendency to twist the pendulum if it rolls down either edge rather than the surface, but I think that would be negligible. If the correct suspension spring is used, it has considerable torsional stiffness and the pendulum bob has huge torsional inertia.

      And I still suspect a straight ramp is as good as a curved one. If I were making this part, I’d make the flat ramp long enough that the roller would land below the top of the ramp and be lifted off before reaching the bottom. This is what Gents’ does and it extracts all the potential energy available in the time the roller and pallet are in contact with each other.

 

2.  I believe the 45-degree facets are intended to act as elastic hinges where thin material embraces the pendulum rod. But they are so long that I’m not convinced that a single 4-40NC screw in brass will be able to generate adequate clamping force around the rod. And the effort to generate enough clamping force will likely strip the female thread, leaving you with no clamping force at all. The safe way out is two screws, though there is still risk of stripping one of the female threads if they are tightened unevenly.

     You’ll likely be starting with .50-inch thick stock, or maybe the nearest metric equivalent. There’s really no need to machine it down to .44 inch thick, nor is there a functional need to machine the two 45-degree facets on the end opposite the ramp; only an aesthetic one. Nor is there a need for the counterbore if those facets are omitted.

 

3.   The .035 dia. thru hole gives the gathering arm a place to be, but I don’t see what keeps it there unless the 2-56NC hole below it is part of a retaining scheme not shown. The original pallet part, of course, has an elegant but complex retaining scheme machined into it that was wisely avoided in this design.

 

4.   The .38 radius on the underside can actually be any radius that’s convenient. It does happen to match the specified radius of the ramp.

 

Kind regards,

Steve

 

Stephen Hibbs

PO Box 536

Markleeville, CA 96120

530-694-1045

 

 



On Feb 19, 2021, at 1:29 AM, Norman Heckenberg <heckenberg@...> wrote:

 

<pallet.jpg>

 




--
Naing <IMG_20210220_191411.jpg>


Re: Synchronome contacts pitted

N Linn
 

Hi Eddy,

Thanks for the message.  The serial no. reads 707. Kindly see in attach for your reference. I'm not very well understand about these parts. But i saw some videos on youtube similar to this clock. 

Best regards,
Naing

On Sat, Feb 20, 2021, 3:32 AM Odell, Edward via groups.io <edward.odell=kcl.ac.uk@groups.io> wrote:

Hi Naing,

 

In the picture you sent with your first post, the movement that you have looks to be an interesting and early example. It does not have an overthrow damper for the gravity arm and it has the early type of latch. These early clocks did not have the later standardised impulse pallet, they had a much shorter curve which was less efficient. It probably does not matter exactly which curve you make for your clock so long as the contacts close before the roller reaches the end of the curve.

However, it would be interesting to know the serial number of your clock. This is stamped into the bottom of the NRA plate. I can make out a 0 in the number but I cannot see the exact number. If the number is very low this could be an interesting movement historically and it would be good if you could let us know the serial number. We might then be able to tell you which design of impulse pallet match the date of your clock

 

Eddy Odell

 

From: synchronome1@groups.io <synchronome1@groups.io> On Behalf Of Stephen Hibbs via groups.io
Sent: 19 February 2021 20:51
To: synchronome1@groups.io
Subject: Re: [synchronomeelectricclock] Synchronome contacts pitted

 

Hi, Naing,

 

I can’t seem to get Norman’s .jpg to download. Wish I could see it. But as a mechanical engineer who has designed thousands of parts for manufacturing, I have some comments about the .pdf from bailey.services that might simplify its fabrication with no loss of functionality.

 

1. The curved ramp is shown as a segment of the developed surface of a toroid. Again, this could be simplified. If it was simply the surface of a cylinder instead, it could be generated by the simple motion of a milling cutter instead of a complex motion, if you follow me. The roller on the Synchronome’s gravity arm won’t know the difference if it is truly rolling instead of sliding (which it might do if its pivots aren’t sufficiently lubricated). There might be a very slight tendency to twist the pendulum if it rolls down either edge rather than the surface, but I think that would be negligible. If the correct suspension spring is used, it has considerable torsional stiffness and the pendulum bob has huge torsional inertia.

      And I still suspect a straight ramp is as good as a curved one. If I were making this part, I’d make the flat ramp long enough that the roller would land below the top of the ramp and be lifted off before reaching the bottom. This is what Gents’ does and it extracts all the potential energy available in the time the roller and pallet are in contact with each other.

 

2.  I believe the 45-degree facets are intended to act as elastic hinges where thin material embraces the pendulum rod. But they are so long that I’m not convinced that a single 4-40NC screw in brass will be able to generate adequate clamping force around the rod. And the effort to generate enough clamping force will likely strip the female thread, leaving you with no clamping force at all. The safe way out is two screws, though there is still risk of stripping one of the female threads if they are tightened unevenly.

     You’ll likely be starting with .50-inch thick stock, or maybe the nearest metric equivalent. There’s really no need to machine it down to .44 inch thick, nor is there a functional need to machine the two 45-degree facets on the end opposite the ramp; only an aesthetic one. Nor is there a need for the counterbore if those facets are omitted.

 

3.   The .035 dia. thru hole gives the gathering arm a place to be, but I don’t see what keeps it there unless the 2-56NC hole below it is part of a retaining scheme not shown. The original pallet part, of course, has an elegant but complex retaining scheme machined into it that was wisely avoided in this design.

 

4.   The .38 radius on the underside can actually be any radius that’s convenient. It does happen to match the specified radius of the ramp.

 

Kind regards,

Steve

 

Stephen Hibbs

PO Box 536

Markleeville, CA 96120

530-694-1045

 

 



On Feb 19, 2021, at 1:29 AM, Norman Heckenberg <heckenberg@...> wrote:

 

<pallet.jpg>

 


--
Naing

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