Here's my first attempt at a tool for making tool height adjustment easy.
The Problem:
To quickly set the Z-axis zero.
What I Was Doing:
Place a card of known thickness under the tool, and keep moving Z down until it was just scraping as I slide the card around. Then you can type in the appropriate adjustment. Unfortunately, it's very hard to consistently move the tool down by tiny increments. Sometimes, it jumps, digs into the card, and I'm not really sure if I lost counts. Even when it worked, it was very tedious.
New Solution:
I bought a "Machinist's Dial Indicator" from Harbor Freight:
http://www.harborfreight.com/cpi/cta...Itemnumber=623
(it was on sale for $10 when I got mine), and mounted it upside down on a piece of angle Aluminum. Then I put a small plate on it. Placing this under the tool (you have to lift the Z way up), I can move the tool up and down until the dial shows zero, and then I can just enter the known height. It's actually very easy to adjust and going slightly over is no problem thanks to the spring-loaded pin.
It's not a perfect solution, but it's better than what I was doing. It also makes it really obvious how inconsistent my attempts at jogging really were...