THE FLETCHER DT TIMER
This timer was built by a man in Australia a number of years ago. The information is presented to our customers as a service to those who may be interested in creating their own timers from our raw plastic clock. The key thing to notice is the left hand thread scroll and the way weights are added to the internal speed regulator of the plastic clock to slow down the rotation of the output shaft (scroll). The one we used for the photos is capable of 6 minute DT times. The weight of the finished DT timer is about 5 grams. A pin is used in the faceplate hole to stop the timer until it is time to start it. We can not offer any more assistance than what is shown in the photos. (note the messed up threads on the scroll are my doing, and not the way the Fletcher timer was made)
The advantage of this sort of timer compared to the viscous fluid (Button or Badge) type is the amount of line pull is not critical for timing and it is not sensitive to temperature changes. And, of course, it is much simpler to use than an electronic timer.
A quote from Sergio Montes of Tasmania regarding this posting:
Thanks for showing these clear photos of the Fletcher timer, and re-stating
the advantages of the mechanical timer over the viscous timer.
This timer was the product of Jon Fletcher from NSW, Australia.
Unfortunately production of these excellent timers ceased quite a few years
ago and they are eagerly sought items now".