CNC by Jim

[jmc]

Here is a screen shot of the machine concept that I have and have already have started to build some components.
Any advice or suggestions would be good, I will try to keep a good log for everyone to follow.
Any questions welcome.
There are more screen shots in the photo album.

[acondit]

Jim,

Here is a link to my thread. I have done pretty much the same thing.

http://www.cnczone.com/forums/showthread.php?t=10425

Let me just suggest that the more width you can get between the rails the more stable your axis will be.

[jmc]

I like your z axis I was not happy with the way mine came out (not enough travel) and thought I would change that.

I have accually built it to the drawing but it will not be a huge deal to change.

Do you notice any flex in your router mounting plate when the Z is fully down?

What is the # on your thompson bearings? they look exactly like the ones that I am using (I took a copy of your template just in case, Hoping thats ok)

Thanks for your advice
Jim

[acondit]

Originally Posted by jmc I like your z axis I was not happy with the way mine came out (not enough travel) and thought I would change that. I have actually built it to the drawing but it will not be a huge deal to change. Do you notice any flex in your router mounting plate when the Z is fully down? What is the # on your thompson bearings? they look exactly like the ones that I am using (I took a copy of your template just in case, Hoping thats ok) Thanks for your advice Jim

My z-axis uses 3/4" Thompson rails and I have 9" of Z travel (currently). There is some flex but it appears to be more in the Thompson bearings than in the plate or rails.

I am thinking about reducing the travel to 6" or less and adding a second set of bearings. But before I reduce the travel I may try replacing the ball bearings with bushings. I have several Thompson 3/4" bushings (FNYBU12L) that are a direct replacement for the ball bearings (or as they call them ball bushings). The part number on my 3/4" twin bearing blocks is SSUTWN12.

If the bushing help out I may also replace the bearings in the X-axis and Y-axis with bushings. They are 1" rails and bearings and are adjustable for fit. You get them too tight and they will hardly roll, too loose and you get flex in the gantry and/or Z-axis. Its a delicate balancing act.

On the copy glad to help.

[jmc]

I guess my bearings are different than yours alcondit diffrent part # (not that it matters)

Still contemplating what to do with my z axis.....wondering how much stability I will gain by moving my rails 1 or 2 inches farther apart??

Tried to draw up the X axis to see how that was going to go, after a day and a half decided just to go to the shop and mock one up......what a shame such good software and me with no talent tring to use it.

I have been tring to upload a pic of where I am at but it is taking too long (stupid dial-up) I will try again later for now it is back to the shop.

Jim

[jmc]

Here is the Pic of the X axis mock up....you can probably tell it will be a stationary gantry.
I decided to spread the Y axis rails out farther and have completed this task however I will have to redesign my z axis it would have been nice if the z would have worked as is as it was an easy solution as I had to do very little to make it work below is a pic of what it was.
Jim

[acondit]

Jim,

The y-axis image is so small it is hard to see the detail.

Alan

[jmc]

If you are talking about the bottom pic, that is acually the Component that I used to make my Z axis.
What it used to be was a Bimba thruster....we use them at work, when the pneumatic cylinder wears out we toss them, I thought perhaps they would be a good start to my Z but I am starting to rethink.

check them out here
http://productpage.3dpublisher.net/3...=1013539704453

Jim

[jmc]

Running into problems building my X axis table as you can tell by the pics from a couple posts ago I was planning on using some used 2" square tubing that I had lying around.....the problem I am finding is that it appears that some of the sections are bent and that makes it very difficult to square the table up along with that comes the realization that I will have to spend a bit of money for paint stripper to strip the paint off all the sections that I have cut(messy too). I will square up what I have the best I can and build a nice flat welding table and source some new material today for my router.
Jim