Gina

Update...

I used bigger ones - 120mm - and round groove. Same make. Four carry my roof superbly.

With frame.

More added.

Even though I do remote imaging I didn't think it worth bothering with motorising the roof though I did get a motor, sprockets and chain for the job. When not in use I have the roof securely locked down so if I'm going to unlock it I might as well open it - only takes one finger.

A couple of changes needed - the peg on the rack lever wants to be smaller and the small snail cam also wants to be smaller. A couple of views of the latest clock assembly.

The striking mechanism - more parts to add yet. Shown about to strike 12 o'clock. The snail cam rotates anti-clockwise and winds the rack up one notch whilst striking once per revolution. The pawl holds the rack as the tooth on the snail cam leaves the rack. Once the appropriate number of strikes has occurred the tooth on the small snail cam contacts the lug on the end of the rack and stops. The mechanism remains in this state until just before the next hour when a cam on the minute shaft causes levers to hold the small snail cam and lift the pawl, releasing the rack, which drops until stopped by the peg contacting the large snail cam (brown). On the hour, the small snail cam is released and the pawl dropped onto the rack and the next hour strikes.

Only fit for single use and throw away anyway! It's pointless buying decent brushes for that task - a few stray hairs won't matter.

Next I shall be adding the parts of the striking mechanism. The parts I had already printed were the wrong scale. First component is the strike cam. The spokes of the cam fit the spokes of the hour wheel. The cam goes behind the hour wheel and will be glued to it.

CAD screenshots of clock "going train" - the set of gears going from the chain wheel to the escapement plus the drive to the hands. Viewed from front, left side and top.

Me too! ?

The water based adhesive shouldn't have and inflammable fumes. Can't remember now.

I think I may be wrong in going for a very large escape wheel. Metal longcase clock mechanisms have quite small escape wheels of 50mm or less so my original 100mm diameter wheel was already much bigger than standard pendulum clocks with a one second pendulum. I have found out why my earlier recoil anchor escapement gave problems - the pendulum bob was far too heavy. With the new lighter bob the earlier escapement may work.

Come hell or high water I shall get this clock ticking!!! Just maybe not today!

Unfortunately U4 is not a transistor but an IC with 6 connections. I guess only ZWO know what it is/was.

Still not working! There are so many interdependent variables with the deadbeat escapement that I've decided to leave it for now and just make a recoil type escape wheel so that I can get the clock working. I hope to return to the deadbeat escapement later.

Still to much overlap of pallets and teeth so have shortened teeth by 2mm to try again. Now printing.

That's a sincerely nice scope though...

Well, if you don't know who am I to tell you? ? ?

I have split the drive phase over two parts including an arc for the shape of the escape wheel tooth "point" making it easier to print accurately. The hold part is basically 1mm or up to 5mm providing tolerance for the driving force. The resulting escape wheel looks like this :-

The escapement needs far too much pendulum swing. To make this design of deadbeat escapement work would mean a much bigger escape wheel so that 3 or 4 degrees of pendulum swing make a significant movement at the pallets. Applying geometry, the amount of movement on the end of the current anchor arm of 90mm for ±2° swing will be 90 x tan(2°) = 90 x 0.035 = 3.14mm. For a deadbeat escapement this means splitting this already small distance into two, for the two phases of lock and drive. This might just be possible with very accurate design and construction. The pallets are 6mm OD ball bearings which means the minimum drive distance is 3mm with pointed teeth on the escape wheel. Any radius on the point (to make it 3D printable) will add to the drive phase distance and hence angle. With a 0.4mm nozzle the "point" has a radius of at least 0.2mm depending on extrusion factor giving a minimum of 3.2mm drive distance, corresponding to a little over 2° of pendulum swing. The maximum swing the pendulum can have without bumping into the case sides is ±90mm which corresponds to ±5°. This is more than recommended for good timekeeping but that can be corrected. I does need more drive power though. Allowing ±4°would mean a ±6.3mm swing at the pallets ie. 3.3mm of drive and 3mm of hold. This supposes an accuracy of a tenth of a millimetre - difficult! - but if we allow 1mm accuracy the hold phase could be designed for 2mm.

New deadbeat escapement.

I used all water based adhesive on my rubber roofing, fastening the edges up under the timber with either strips of wood or just roofing tacks. It's survived 7 years with no problem.

Cleaned up. U4 may be dead but what is it??

I think this escapement might just fit in.