Bought some diamond coated cutting wire on Ebay. To use it I made this hand saw:
The bow is made from 3mm laser cut steel. Handle from 4mm plywood covered with shrink wrap. .DXF here
After realizing that this thing will literally cut through everything (except diamond) I thought it could be interesting to make a CNC machine that could do just that. The following are some of my experiments in that department.
Existing motorized wire saws usually use a loop of diamond wire, much like a band saw. I did not want to use this approach since A: I didn’t have a good way to make a loop of the wire I had and B: I wanted to be able to use bits and pieces of wire and not discard the whole piece if it broke. In stead I decided build a reciprocating bow saw. Above is the first attempt. The bow is mounted on a linear bearing attached to a base plate. A crank and connecting rod creates the reciprocating motion. The whole assembly would have to be mounted on some kind of structure and the shaft be turned by some kind of motor.
Not satisfied with the mounting of an external motor I changed the design to be driven directly by a stepper motor.
Since the wire is lubricated with water I realized that the assembly needed to be mounted upside down to prevent water from getting into the bearing and motor. I therefore build a gantry structure to hold the mechanism.
For the CNC part I needed some kind of XY motion control. I ended up using parts of a auto sampler (thank you local dumpster). This had all the moving parts I needed, including the linear bearing for the saw.
Last thing I needed was a clamp/vice to hold whatever is being cut. I made a simple ‘filing clamp’ of 3mm steel with some rubber for grip.
Initial results are promising. Above squiggle are cut into a 1mm microscope slide. A 1mm hypodermic needle for compairson.
I will post about future progress.