Roly wrote:Awesome, that is something I have been tryong to get into for ages.
How did you cut the gears. I am having big problems getting anything like that to cut properly. Is it possible to post the crv file for one gear which would give me a good start to understanding how to go about cutting the others.
There's a link in the original post to Gary's site with the design - there's a dxf file there with all the gears and PDF's explaining the construction in detail. It's well worth looking at the site - there's lot's of information there on making clocks. I'd post the crv but even though I've altered the design substantially, I'll email him first to ask permission.
What I did was import the DXF and scale all the parts to the size I wanted, which was basically governed by the smallest router bit I had available (I drew a circle of the bit size in VCarve to make sure the cutter could get far enough into the gears - especially the escapement wheel, to make a decent cut) and making sure the largest gear would fit on the bed of the machine. Each gear in the dxf needed some work - I used the join open vectors on the gears to sort out the fact that the dxf was a lot of separate lines. That gave me a good object to work with for setting up the toolpaths.
The key in getting the clock to run properly despite having scaled everything by some arbitary amount, is to keep the pendulum size the same. The geartrain is effectively designed to operate at a certain frequency which is governed by the pendulum length. So even if I scaled the thing down to be only a couple of inches wide - I'd still need a pendulum over 1m long! As it happens, I had to scale the gears up, since my smallest cutter size was 3.2mm.
I have to admit I didn't follow the pinnion design - using straight 6mm dowel throught. However, they are all mounted into metal bearings which should help keep the mass of the weights down.
Hope that's helpful!