[Overtorque]

Hello,

I've been daydreaming about making a CNC bed mill out of steel. I have very little machining experience, so my questions may seem basic to most of you.

Please take a look at the homemade bed mill in this post, and take note of the screws that I have circled. I'm guessing that the best way to drill these is with a mill, however in my design, the weight of the z axis plate may be too much for my knee mill (possibly). Is there another way to drill these holes perfectly? A magnetic drill, perhaps? Or should I just farm this out to a machine shop?

I could also use precision angle plates (see attachment) on the inside of the z axis, but I would still run into the issue of drilling perfectly perpendicular holes.

Part of the reason my Z plate will be so heavy is that I plan on using my existing knee mill's head on the new bed mill. It's got a 5hp motor and looks like it weighs at least 300lbs. I plan on using a design similar to Southwestern Trak bed mill's (except no cast iron, only steel).

I would also like to avoid welding (with the exception of a few tacks here and there), as I don't want to transport this machine to get it stress relieved.

Thank you in advance for your help.

[Zenji]

My advice would be not to kill the goose that lays the golden, if you get my drift.
Buy a benchtop mill to convert to cnc and save the big knee mill for horsepower cuts on steel blocks, etc.