ZTO top surface - how hard?

[RCaffin]

I have seen ZTO units with flat brass as the contact surface, and with flat carbide as the contact surface.

Brass is softer so there is less risk of damage to the tip of a cutter (unless it is a micro engraving point!), but that means the top surface can be damaged and will vary slightly over time.

Carbide does not get damaged and will keep the precision, but could damage the tip of the tool if you bump it too hard/fast. But then, the head should not be moving that fast anyhow, and the touch plate should be sprung somehow as well.

Comments or thoughts as to which is better?

Cheers

[RomanLini]

I made mine very hard, but sprung, requiring about 300g to depress. It has not broken or damaged any tools, but the zeroing is done very slowly about 1mm/sec and lifts the moment the tool is detected.

My first plate was 304 stainless steel, it showed no signs of wear and no scuffing. I recently re-made my tool setter lower and put some glass as the top surface. It's harder than the stainless I think. I'm not worried about any wear or damage due to the hard materials and very low force and low frequency of use;

http://www.romanblack.com/RandomPics/ztool.jpg

[RCaffin]

Hi RomanLini

Ah ... that's a totally 1-D ZTO? Blimey! I had not been game to go that minimal.
How well does it work?

Cheers