Dead simple lathe tool height gauge

[Toolmaker51]

Total agreement on the utilization of fingertip as an indicator. The more users do it the better they'll get. Never understood why 'center height' was made so mysterious. Spirit levels, LED lights, or devices contacting the tool's top edge...waste of money unless there isn't a convenient reference surface like some CNC's.
Bottom edge benefits from that relieved area. Can press in 3 bearing balls instead, hard very long lasting contact and ultimate avoidance of debris.
I make one for each lathe. Mine have 2 steps; one as it rests on carriage if flat, or a bed resting on ways. The step checks height on the compound - for setting turret tool posts. Saves dropping shims into the chip pan. Tip: In QCTP, set small boring bars in left dovetail first.

May I add how to determine center height? Turn a diameter, measure it, and record the dimension divided by 2 [half]. Then from top of carriage, or aforementioned cross bed over the ways, or top of bare compound; touch off height gauge on top of turned section. Subtract the half diameter calculated prior. Result is center height. Make a card, use a felt tip, but attach it to headstock. That also is target dimension in machining Marv's tower for yourself.