After having a look through the newsgroup archives, without success (but some 5-year old hints from Kaukler on 6/6/1999), may I ask here for any information related to the cutting, grinding and polishing of a metallic Zn single crystal (1"-thick, 1.5"-wide, -oriented)
Would wire erosion be a possibility for cutting? I assume you don't want any thermal effects or deformation. What are the requirements on the crystal for your experiment? Mechanical cutting will damage the material quite a bit.
Careful wet grinding over at least 4 steps to 1200 or 2500 grit paper may be necessary until you start polishing. Polishing will also need again at least
4 steps to 0.1 micron poilishing compound to achieve a mirrorlike finish. Always use fresh paper in every step and do ultrasonic cleaning before using the next finer grit (grinding and polishing). In every step, rotate the sample by 90 degree and grind until all the marks from the last step are gone. Not more and not less, both is bad.
For polishing is done in random directions, not unidirectional like grinding.
After polishing clean the sample in ultrasonic again and rinse with acetone (quality: puriss. p.a) blow dry from one side with dry nitrogen or a hairdryer.
You could use vibratory polishing to get as little deformation to the material. The sample can run under its own weight, although it will take a long time. The best idea is to get a detailed book on metallography, i'm sure zinc preparation is described somewhere. At the moment I can't tell you what will work definitely.
If required, a final annealing under inert gas should remove residual stresses and surface deformations after polishing. The preparation technique strongly depends on your final requirements on the sample.