View Full Version : Idea for 4X4 hybrid

11-29-2008, 03:36 AM
I have been a lurker here for a month or so now and I am planning to start a build after Christmas, I give all my spare money to the grandkids at christmas time. Anyway I noticed over at www.buildyourcnc.com there is a pic of Octavio's Metal CNC Machine that I found interesting. I thought I would bring it up about the way he used the same bolt for both the Z axis and Y axis bearings. I have drawn a Sketchup of something that I would like everyone to digest. Perhaps it could be a mod for the 4x4 hybrid or something.

11-29-2008, 12:54 PM
Personally, I do not like the idea of one axis Dependant on another, can cause havoc trying to diagnose and fix a problem on an axis, which can trow another one off. I like mine to work independently.


11-29-2008, 05:44 PM
Not sure but don't thank you would be happy in the long run.

My Z has a small set screw on the two left v-wheels as you look at it from the front.
This is to take out any "play" left-to-right. Same on two of the Y v-wheels to adjust the up-down. After taking out any play with the set screws you then tighten down the nuts.

Not sure how you would be able to make the same adjustments easily on the v-wheels sharing the same axle on the z and y axis.

11-30-2008, 12:37 PM
Yes I can see what you mean. I was just curious as to how the box that moves along the Y axis could be strengthen in some way, make it more stuff you might say. I was just thinking along the lines of making the box that gets used as the Z axis holder less part of the torsion between the Y axis and the Z axis.

The way I see it, all the g-force from the router head travels through the Z plate then the Z bearings then all the way through the box to where its mounted to the Y axis. If the route could be shortened in some way there would be less energy passing through the Z box and as such that box could be made with less meterial. The box would be there only to hold the Z axis motor and screw. Not as part of the torsion between the Z and Y. That would also possibly increase accuracy.

The problem of the set screw to adjust pre-set is solved by drilling a small hole in the edge of the Z plate at 45 deg. Putting a bolt in this way would put presure on the v groove bolt at 45 deg. causing both inward presure and downward presure for both Z and Y

11-30-2008, 03:32 PM
We use eccentric and concentric bushings for the bearings to take make the required adjustments.