very small scale projects, smallest possible engravings

[Glad]

Hi guys,
I’m working on a very small scale projects like wrist watch cases, dials, bridges and main plates. Sometimes machining new parts and decorating movements inside and out. As a result I’m trying to do the smallest possible engravings on brass and steel. Diamond drag is not an option; it wouldn’t give me enough depth to change color of the engraving. If any of you had any experience with small scale engraving please respond. Here is an example of what I was up to: letters on the photo are 1mm high and 0.5 mm wide.
Glad.

[JD_Mortal]

Well, I can tell you that you want to have parts with the tightest tolerance possible...

You should get nema-17 motors with high precision, 8-wire, bipolar, 0.9 deg, 400-step motors. Drive-screw should be greater than 20-turns per inch, which would be most 1/4 inch machine screws (1/4-20X6"). Drive-screw length should not be longer than 6", for both X and Y axis. Z axis can be the same, but for superior depth control, use a metric (8-32x6") machine screw.

Use a pencil air-drive, jewelers engraving tool and bits.

Keep your drive-screws as close to the working area as possible, with double-wide glides for the most accurate precision. Eg, that 6" thread should only give you a 3"x3" XYarea with no more than 3" of Z lift. 3" of that lead-screw should be used for the mounts...

Mount area in the center. [=]mount-plate[=]
######[=]############[=]######

Use super-small RC helicopter bearings, or printer-slides. You can get them by the hundreds, for about $20.00 USD.

Get a good set of digital calipers, and measure measure measure. Invest in a small metal lathe, you may need a lot of custom parts that can't be purchased for less than the cost of the lathe. (From wear and tear.)

Stainless-steel, all the way through... Polished, if possible, chromed if not possible to polish. (Chrome chips in time and can't be "fixed", polishing can be re-polished and re-ground if needed.)

[Glad]

Hi JD,
Thanks for the response. I hope over time I’ll be able to change my current setup to “ideal” configuration described by you. I wonder how much setup like that could cost. Well, one day…

Glad.