[skyguynca]

Ok, I did Hoss's cnc conversion 2 years ago. I have had no problem with it except wearing out gibbs. So I opted to do the linear rail conversion using my old column but to keep using my machine I purchased a new column and installed it so I could use my machine while I work thru the linear rail installation on the old column that has the worn out ways.

Well I took the whole machine apart and cleaned it, installed new gibbs with the re-installation of the saddle and the table.

In going thru the setup for movement accuracy and backlash, as I have done every time I go thru gibb replacement, I noticed that my table was .002 Higher on one end.
I took it apart and checked to make sure under the saddle was clean and not causing the table to be at a very slight slant, but all was good.
I checked the ways on the table, all is good.

Now I know the column is within .0005" at the full travel of 14 inches true 90 degrees to the base.
the saddle is true to the base within .0005 at full travel of 9.7 inches. (yes I have both of Hoss's extension mods installed)

So with both so accurate how is it my table from one end the test indicator does not move more than .0005 over 8 inches, then climb .002 linearly over the next 8 inches?

I even tried reinstalling the tooling plate and faced it, the mirror finish on the aluminum tooling plate shows the head is correctly trammed, yet when I attached a test indicator to the head
and then run the table full length and still shows the first 8 inches is withing .0005 and then it starts a steady climb of .0005 every 1.33 inches of travel until it max out at the end of .002 rise in height.

Please throw all suggestions at me so I can try and fix this.



David M.
San Jose, CA

[skyguynca]

It is fixed now, I took it apart again, I worked the table back and forth and found binding in the last 8 inches of travel. It was not found during reassembly of the mill. That is because the gibbs were not fully seated. The final adjustments made to stop any play in the table, saddle or column had not been made yet. When they were made everything was moved with the steppers and the gibbs were adjusted to take all slop out.

Well it ended up being the gibbs I received from Grizzly. I put the new gibbs in with the steppers disconnected and slid the table end to end and after a adjustment I could only move the table half way before I could feel the binding starting and getting worse towards the end of the table. It would get so tight I would need a rubber mallet to move the table back past the half way point so it would be loose enough to move by hand.

The Y and Z gibbs are OK, but the X gibb is slightly greater in taper from thin to thick and in height.

I put the old X gibb back in and everything is fine, back to normal.

David M.
San Jose, CA

[CL_MotoTech]

I had a similar issue with a new table. The new table hung up on the ballnut. I had to adjust the underside of the table with the 4" grinder.