Alignment

Now that the Chinese New Year celebration is over, & the main machine structure is up. It is time to proceed with the critical rail alignment work.

This is the most dreaded part of the build. Why so? We all know that we can ride smoothly on a bumpy & winding  road. It is the same with machine. without a through rail the machine can never travel straight & smoothly.

What is the primary objective ?
1) line the rail as straight as possible. Here, I set out for within 0.1mm which is equivalent of +/-50micron. which is about the diameter of my hair (which I had just measured...)
2) straightness of within 0.2mm along the 4.4m length x-rail & 1.73m y rail
3) parallelism between the 2 x-rail of 0.2mm

Secondary objective?
1) Using the most primitive tools & equipment I can lay my hands on in my tool box.
Tools I used
1) Filler gauge with 0.05mm to 1mm
2) 30 lb fishing line
3) Aluminium shim salvaged from Coke can.
4) Hole punch
5) a few clamps
6) an aviation straight cut snipplet
7) some spanner
8) a 3lb hammer

No rullers, no micrometer, no dial gauge, no vanier calipers...

Can this be done? Oh Yes.
The last time I lay my hands on similar work was like 2 decades ago, after which I get to supervise/instruct others just by pointing my fingers + a bit of shouting when it calls for ;) . While they slough it out in tropical heat, I get to take refuge in nice air-conditioned office sipping coffee. The for another few year, I don't even get close to job like these...

It was tough at the beginning when I got rusty over the years, but like riding a bicycle, everything came back after a little fiddling.

Will post more on details... once I get everything organized...