The only other idea I've had was to use the mill to cut the setts into a dried sheet of Das.
Heather,
Your wish is my command.
I rolled out a bit of DAS on Wednesday to about 3mm thick and left it to harden for a couple of days, then stuck it down on the mill table and had a go at it.
...and the first thing I found out was that it is quite difficult to roll DAS completely flat.
I had to keep dropping the cutter by 0.1mm at a time to try to cut the left hand end meanwhile ploughing deeper and deeper into the right hand end.
So I then tried doing a surfacing cut with a 5mm cutter to get a completely flat surface. I wasn't sure how this would turn out - i.e. that the surface would look too flat.
I then cut the pattern again to o.1mm depth with the 0.2mm cutter and cleaned it up and finished it off with a softish glass fibre brush, and it looked not too bad.
I then tried a slightly deeper cut with the 0.2mm cutter, which made a slight difference, but not as much as I thought.
I also had had a discussion with TimC about the setts, and the size of the setts cropped up. I had been aiming for a scale size of 4" wide by between 4" and 12" long. If you apply the three foot rule, then I suspect that these setts will not show so we thought about scaling them up. I had made another sett drawing and I tried upping the size of that and trying it.
First at 0.1mm depth...
...then at 0.2mm depth. It cut quite well but I think I went a bit too big. It is almost 7mm scale size.
So I'll have another look at the scaling factor.
But overall I was quite pleased with the results. The machined flat surface is not quite so apparent as I thought it might be and the cutter leaves a slightly rough edge to the setts which takes the edge off the machined look, and a bit of brushing with a soft glass fibre brush takes a bit more of the edge off.
I might do a bit more experimenting with the width of the cut. I used a 0.3mm cutter on the larger sized setts and I think I could probably have gone up to 0.4mm, or maybe even 0.5mm. I might also go a bit deeper with the cuts, thinking ahead to when we have to paint and weather the setts, when shallower cuts could fill up with paint.
Since this looks as though it will work, I'm contemplating machining largish sections - maybe up to 6" x 4" - to fit between tracks and between the tracks and the baseboard or building edges, then it could be a fairly quick process to stick them down, like carpet tiles.
I've also got all the accurate dimensions of the four foot way from Templot, so I could machine long strips of setts to go between the rails, and also all the "funny" bits to fit in all the areas in the formation.
I also had the idea that I could be doing brickwork for buildings using this method - the CNC answer to laser cutting.
Jim.