Building a Cnc Router

[kong]

1/4" ali will still flex. I added some ali angle bars under my table top to help control the flex. Seems ok so far, and they just clear the leadscrew/nut assembly.


What in particuar are you having problems with on the z axis? Sorry, I don't quite understand!

[Cold Fusion]

The Z axis still needs work.

[kong]

Go take a look at Balsamans z-axis, he got it sussed! The use of an ali plate on the slides will leave just enough room for your leadscrew. Hope this helps!

[Cold Fusion]

Update. I got off the phone with a friend from a cnc shop. The Z axis will be using 7 inch long Sr20 THK rails. I'm going to have him machine the ballnut mount, both z axis plates, and the motor mount. I also have the chance to pick up a pair of 8mm SKF ballscews for my Y and Z axis for a great price. There are two things I'm concerned about though. Shaft whip on an 8mm screw over 29" could be a problem. Also, they are single nuts. Is this going to be a big problem concerning accuracy? I really want the machine to run soon, but then again, I want it to be as nice as possible the first time around. I am also considering buying 5/8 thomson ballscrew and preloading my own nuts. Please help!

[Cold Fusion]

1

[Cold Fusion]

2

[Cold Fusion]

Muahaha, I finally got a Z axis. It's a little too long now, but I'll be modding it to fit. http://cgi.ebay.com/ws/eBayISAPI.dll...category=42899

[Beezer]

Man "Cold Fusion" you really scored a fantastic deal on that Z-Axis setup. You don't see sweet deals like that come up often. Nice job.

[Cold Fusion]

Seems like there are always Parker slides on ebay, but they normally go for around $150. I know that steveald uses one for his 2x2 and his 4x8.

[Cold Fusion]

Question for the experts. Do I really need precision ground ballscrews? I already have one rolled single nut skf and was planning to get the matching one for the Y, but it bugs me that there is something better available Do you think its really worth it? I was hoping to get tolerences in the range of .005 with whatever kind of screws I use.

[Swede]

Cold, since your THK's are SR20's, you may want to place your X rails so that the trucks are horizontal, rather than perpendicular to the ground. SR's have better load capability horizontally. If they were HSR or SHS (4-way load) then they'll do fine loaded in any direction.

OTOH they are so strong it probably wouldn't matter one way or the other. Looks nice!

[Cold Fusion]

Fedex just drove up. It was like Christmas again Centent cn0143 Microstep drivers, Powermaxx 2 hybrid 190oz steppers, 24v 12 amp power supply, and a 5v power supply for my drivers. I bought this whole package from fair451 on ebay, who also sold me my THK rails. I highly suggest him for any cnc parts you might need. I just missed an awesome ground ballscrew from him http://cgi.ebay.com/ws/eBayISAPI.dll...category=25290

I'll spend today figuring out how to wire everything.

Next parts will be the 1.75 inch aluminum squares that most of the frame is made of.

The Parker Z axis should be here in a week. Since it's 12 inches too long I will take it all apart and cut the ballscrew and linear rails down.








And did I mention I'm pretty serious about this project