Not sure of that particular ELS but the one I used you set lengths by entering them in the keypad and the ELS took care of stopping in exact positions.

Are the limit switches more like you get on a powerfeed and just turn the feed off if you get to the end of safe travel? Same with a CNC the limit switches are at the extremes of travel to save a crash.

Look on the Honeywell website for precision microswitches. I seem to remember these are good for 0.025mm or better stability, though subject to quite a few to specific mechanical and electrical conditions to achieve this. Don’t be surprised if the cost is similar to your lead screw, though I could be wrong about that.

Further to what John Haines says repeatability is generally more important than absolute accuracy for things like end point detection.

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According to Mrs Google :-

A standard V3-size snap-action micro switch typically achieves a repeatability of roughly ± 0.01mm to ± 0.05mm (approx. ± 0.0004 to ± 0.002 inches) under well-controlled mechanical conditions, though real-world performance depends heavily on the setup.

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Absolute accuracy tends to be strongly influenced by mechanical play which inevitably varies between switches so simply swopping one switch for another “the same” will give different trip points. Highly commoditised switches such as teh V3 series will show even greater variations as different makers not only have different quality standards but also do the innards a bit differently. Basic V3 units vary from around £ 0.50 to almost £ 5.00 but but the premium versions go up to £20 a pop and beyond. For example Honeywell 19M.

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Mrs Google says :-

Loose components, roller rings, or hinge pin tolerances in lever-equipped V3 switches can introduce errors typically ranging from 0.003 to 0.007 inches (0.07mm to 0.18mm) according to machine-shop user data.

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In practice well controlled mechanics giving repeatable approach to the switch at the same, reasonably slow, speed every time will take up all the mechanical clearances in the same way over the same distance. Variations of less than a thou can be observed from a well made commodity V3 switch. Even the 50 pence cheapies can be surprisingly good. If you are lucky. Changing the approach speed or direction relative to the switch plunger will generally shift the absolute switching point.

Clive