I've made 3 lapping plates from some store bought 5lb cast iron weights I found on amazon. It has worked out very well so far but I had a few questions.
1. how stable should I expect them to be or is it a crap shoot? I cut 1mm depth grooves in a 10mm grid pattern using my cnc router and it was much easier than I'd expected but I am concerned the stress relieved will cause them to move. How long should you wait after cutting "green" cast iron?
2. after lapping them to 500 grit the groves are very very sharp. The plate shreds a paper towel in seconds and are incredibly difficult to clean. I also understand the groove edges do most of the cutting. Should I deburr and re-lap the plates or leave them "rough".
3. What grit should the plates be lapped to?
4. I found a video of someone who has lapped 3 plates and made some blocks and was able to wring them together. What grit is needed to wring two blocks?
5. I'm planning to make a sphere gauge to test the plates vs a surface plate. I also plan to make a 2 foot twist gauge. What other tests should I use to check the plate? Should I test the contact print from the surface plate?
1. how stable should I expect them to be or is it a crap shoot? I cut 1mm depth grooves in a 10mm grid pattern using my cnc router and it was much easier than I'd expected but I am concerned the stress relieved will cause them to move. How long should you wait after cutting "green" cast iron?
2. after lapping them to 500 grit the groves are very very sharp. The plate shreds a paper towel in seconds and are incredibly difficult to clean. I also understand the groove edges do most of the cutting. Should I deburr and re-lap the plates or leave them "rough".
3. What grit should the plates be lapped to?
4. I found a video of someone who has lapped 3 plates and made some blocks and was able to wring them together. What grit is needed to wring two blocks?
5. I'm planning to make a sphere gauge to test the plates vs a surface plate. I also plan to make a 2 foot twist gauge. What other tests should I use to check the plate? Should I test the contact print from the surface plate?