[RogerC58]

Been fighting the Y-axis for weeks trying to get it to go in without "crunching" when turning the ballscrew to move the saddle Last weekend I took it all apart to start over. Had the saddle off and started turning the Y-Axis ballscrew only to find that it is bent! That explains a lot.

I emailed CNCFusion, several times now, and can't get a response. As I recall, it took weeks to get the kit in the first place. Since it appears CNCFusion isn't reliable, and I can't use the machine in its current condition, I need to source a new Y-Axis elsewhere.

I assume any attempt to straighten the ballscrew would be a waste of time?

It's a thompson 5/8 .2 pitch ballscrew. Anyone?

Thank you,
Roger

[banny]

Hi RogerC58
I have being contacting CNCfusion by email. But nothing respond.
I also want to get LMS 3900 XY axis kit such as CNCFUSIONs.
Does anyone know the cncfusion company's activity?
Or is there any other CNC plans for large XY table of LMS 3900.
Best regard,
Banny

[banny]

Hi Mr. RogerC58
I had 2 cncfusion mills.
Im sure the screw is Thompsons 5/8 p0.2 is right.
I think straightine the ball screw is not a waste of time . But need power press and experience.
I think the better way is to buy only screw shaft without ball nut.

Banny

[RogerC58]

For others who might have this issue, I have solved the majority of it. The ball screw is bent/oscillating, but I have been able to remove the crunching/grinding noise.

While working on the Y axis I had the X axis off of the machine. It was laying on a table ball screw side up and I reached over to rotate the ball nut back and forth. Just because it was there. That's when I noticed the ball nut was hitting the bottom of the X-axis. I am having the same crunching problem with it, but the ball screw appears to be straight. So if the ball nut is hitting, that could be causing the problem with the X axis. Then I thought, I wonder if the same thing is happening with the Y axis???

I removed the saddle from the machine and ran the ball nut toward me as far as it could go. I then put the saddle back on the machine and slid it toward me. Sure enough, it hit the ball nut!

I turned the saddle upside down and clamped it down on my CNC router table (1.25hp DeWalt DWP611 router spindle) and at 5000rpm and using 1/4" 4 flute end mill I was able to remove a .5" wide swatch down the middle .040" deep (not in one pass, mind you). That apparently gave it enough clearance that it could line up enough to not grind.

I now need to do the same thing with the X axis, but I don't really want to put my CNC router through that again. Not to mention the mess it makes. Can you imagine what the coolant did to my wood spoil board? Just kidding. I used some WD40 and that seemed to do the trick. I do have a mess of WD40'd metal shavings all over, though.