Hi, This is my first time posting. I've been reading, and lurking within the forum for a few month's, and I'm impressed with many people in this forum with their knowledge, and willingness to share. Thank you. Because of this I feel the smartest thing I can do is ask for advice here.
I currently own, and used a home built mill style machine with an ah-ha 4 axis controller. The travel I have, and need is Y - 30" X - 10" Z - 5," and a rotary 4th axis. I have very little knowledge of what's available, and from what I've seen there are so many products available it's confusing to learn what is best. I can do my own machining, and want to make at least the mechanical portion of the machine myself. Finally my question is; What rails, bearings, screws, nuts, etc., would you recommend, if you wanted to make this machine for yourself, I want to build a very sturdy machine, with tolerances at or within .0002/3 max. Speed is not an issue for me. I have never needed to exceed 30 ipm while machining any part, and don't expect more than that in the future. Also 95% of the time it is light load machining, because silver, and shell is the toughest thing I typically need to machine. I use end mills as small as .010", and rarely exceed .030"
I need the accuracy too, because the parts are often no bigger than .050" total in size, and do a lot of male / female part making in this size range, and need tight tolerances. My budget is limited, so I don't want to get crazy, or to much over kill, but will spend further if needed. Mostly I want to spend wisely.
With the fourth axis, I will be doing both indexing, and need to be able to do 4th axis wrap type part making, and engraving.
I'm also going to post a similar question regarding building, or buying a controller in that portion of the forum.
Thank you in advance for any advise, or recommendations.
Dennis

I am assuming that you are building this machine from scratch, so here are some recomendations.

For those tolerances you really don't have many options besides ground ball screws/or precision acme for your drive mechanism. The precision acme will be cheaper, but you may need more powerful motors since the acmes aren't as efficient. You would probably want anti-backlash nuts for the acme.

I would recommend using comercial linear bearings, there are tons that will suit your needs, some that I have found to be accurate and reasonable priced are the vee bearings, superior bearings on the net has great prices and the quality seems good too.

I am sure that others will have some other recommendations as well