A noob's project - help needed!

[tybrenis]

Hey everyone,

I have been lurking on these forums for about half a year now but I never needed to really make a post. Now it's my turn.

I purchased most of my supplies for this project all ready, however, I am questioning the direction I am going in and I was hoping you guys could set me straight.

First off, I should mention I am on a tight budget. I am but a student with hardly any cash, so this project will be a dream come true when it can start paying itself off.

I decided on a Jgro type router. It does not have to be precise at all, I am hoping for only like 1/16" of tolerance. The total dimensions should be about 3 by three feet with at least an inch or two of Z axis travel.

Parts acquired so far:

- 4' x 8' 3/4" MDF
- Stepper Motors
- I have all ready built the controller for the motors
- Power Supply for the Steppers
- Router
- 3/8" rod
- 3/8" 16TPI threaded rod

So this is where my questions come into play. At first, I was simply going to use 3/8" threaded rod as my leadscrew. However, I have decided to use 1/2" 10TPI ACME threaded rod instead.

Second, for my linear bearings, at first, I was simply going to use some greased up tubes sliding over a rod. However, I realize how sketchy that is and that it probably won't work too well on a precision machine like a CNC. I want to make some linear bearings, but I am looking for a simple design that I can do at home, otherwise a cheap solution. As I said, my budget is very low for this project initially.

Third, how do I connect the gantry to my leadscrew? I know I will need some type of leadnut, would it be possible to make one out of delrin? Is it possible to make my own tap or similar to thread it? Also, I don't have a CNC machine to build this with, so it is going to be all hand tools. I do have access to a small mill, drill press, small metal lathe, table saw, bandsaw, belt and disc sander, etc. so I have a fairly full shop.

I know I'm asking a lot of questions, so I apologize. You guys are the best here so I know someone will help me out. Thanks again in advance to everyone who replies!