CNC mill conversion ?s

[autox_vette]

Our team is considering purchasing a small mill with the intent to convert it to CNC in the (hopefully) not to distant future. Right now we are looking at the HF/Grizzly/Sieg X2 class of mills. They seem to be very popular to convert to CNC as there are many different sources of parts/plans/etc. to do the conversion.

For anyone here that has done one of the conversions, can you provide your input on some of the following questions?

Did you use some of the available plans (if so, which one), or did you roll your own conversion? I was looking at the conversion from cncfusion.com. It looks like a well designed kit and incorporates ball screw leads, but it is pricey and it's not very friendly for manual use because it has no provisions for the scales and moves the Z controls to the top of the machine. The scales being gone can be gotten around by adding DROs, but that just adds to the cost.

How accurate can you get with the factory screw leads? Is it worth it to go to the ball screws? From what I read, the Z axis is the worst one on the machine and seems that you would want to convert it to a ball lead if possible.

How big of an issue is the plastic intermediate gear? It would seem that since we will have some inexperienced students learning on the machine that this could be a weak point. It would seem that it could be a good idea to do the belt drive conversion.

Any suggestions on controllers? I was looking at the Xylotex controller. Comments? Any reason to try to go to microstep controller? I would assume no with factory screws? How about with a ball screw?

How much work are we realistically looking at here? It doesn't seem too bad, but given the reality that everything will take at least 3 times longer that expected, what's your experience with it?

Thanks,
Kenton