Calipers and a force gauge! Now we’re talking. (suggestions on a decent/inexpensive force gauge?)
I love this, I know it is probably pissing you off but we can actually check things now.
Giving the belts another click or two on the zip ties, does this tension the belt system enough to minimize that flex a bit more?
Make sure to do all the tests with the bit at the same height, And if you could try one at max extension of your z, and a min. I would love to know the difference.
I use drillman1 on ebay, http://stores.ebay.com/CARBIDE-PLUS, his bits seem legit. I am very happy with them. And the fact that I tried to buy a bunch to get a better price and he said he could sell them to me but not any cheaper makes me trust his prices as well.
Okay so how about just the conduit? 5lbs of force = how much flex? I have 2 kinds of conduit, one from lowes and one from Home Depot. Very different, same OD. Lowes stuff is super smooth but very weak. It mushrooms out from under the bearings very quickly, the home depot stuff has heavy galvanizing that takes a bit to wear off but very little wear on the actual steel after many months of use. I need a force gauge to actually test deflection, Now I have an excuse to write it off on next years taxes…