SeeSaw escapement drawings
by Roger Bunce

SEVERAL people have asked me if I could provide working drawings of the SeeSaw Gravity Escapement. The answer is 'Yes' – well sort of. At this early stage of development (the concept stage), I work straight from the general arrangement drawing and so I can only provide that.

I use TurboCad Delux 2D/3D, Version 4, for MAC. It would be good to provide CAD file so that users could 'push and pull' the drawings to suit themselves, but CAD files, even with the same file extension, are still not compatible between systems - I will not even attempt to go down that route. Similarly, converting from CAD to pdf files is not perfect, but is the best I have. However, if you use a similar CAD system to mine, I would be please to provide you with the CAD files (contact me via the Editor or  

Here are two pdf files containing the GA:

Drg 11, one A4 Sheet.pdf

This shows the complete GA. If printed at 30% full size it will fit on one A4 sheet and will be to scale - at least on my computer/printer).


Drg 11, 8 - A4 Sheets.pdf

This also shows the complete GA but it comprises 8 separate A4 sheets. Each view or subassembly is shown within each sheet. If the sheets are printed individually at 100% and stuck together they form the complete full size GA drawing (A1 sheet) – at least on my computer/printer.

As mentioned earlier, I worked straight from the GA. In fact, apart from the positioning of important holes, which I machined using the DRO on the mill, I simply stuck printouts of the

parts on the material and cut round them! I have shown some dimensions (mm) - just the ones I needed myself. You should find that the major dimensions are nice round figures. I make no apologies for the use of colour on the GA - I think it helps to identify the parts in the various views. Similarly, I make no apologies for 'thin line work' – it helps when measuring straight from the GA.

The article describing the SeeSaw Gravity Escapement, including information on the ball bearings and materials etc, is published in:


Horological Jounal, March/April 2011


NAWCC Bulletin, October 2011


In addition, the YouTube video  

shows the escapement working.

The nearest relative of the SeeSaw Gravity Escapement is the Double Three-legged Gravity Escapement made famous by 'Big Ben'. As mentioned in the above articles, this type of escapement is very good, but not without its faults. I am currently working on a revised design of the SeeSaw Gravity Escapement that addresses these, but a concept model is some months off. In the meantime, if you have any questions about the SeeSaw Gravity Escapement I would be pleased to try and answer them.