I'm looking for some help/discussion about something I recently noticed. I will try to give all info that I think might be relevant.

Hobby CNC Machine, 1605 Ballscrew, Linear Rails, ATC Spindle.

Test performed in aluminum reveal dimension accuracy of +/- .02mm. (.0008") - Performed with a 1/4" bit.

Test performed in titanium reveal dimensional accuracy of +/-.12mm. (.005") - Performed with a 1/8" bit.

In both cases stock to leave was left, and a finishing contour pass was made.

I wanted to get some general thoughts on this. Am I seeing backlash, tool deflection, etc?

I am going to try to do the finishing pass in titanium with a larger bit in order to reduce deflection at some point soon, but wanted to ask. Many of the guys I speak to on the regular only work in Aluminum.

Thank you in advance !