Surfacing Different Across Spoilboard

[jdonley]

I'm setting up a new-to-me early PRS standard (2007). Everything was going along fine until I tried to surface the spoilboard. First pass was out as I expected it would be. But once I aligned the router to the table and tried a second pass, unexpected things began to happen.

The surface is flat and smooth along the front and right side of the spoilboard, but has tool marks on the back and left side. These are pretty distinct marks, enough to catch a fingernail. In other words, the z-axis is perpendicular to the table on the front and right sides of the machine, but not on the left and back sides. Any ideas how to approach a solution?

[gc3]

http://www.talkshopbot.com/forum/showthread.php?t=16866&highlight=tramel+axis

[jdonley]

Thanks, Gene. I saw that thread already. I already squared the router to the table. It cuts nice and smooth in the area where I squared it. But it isn't perpendicular at the opposite end of the table. It's like the router slowly tilts as it approaches the back left corner, then straightens up again at the front right corner.

[Red F]

I'm fairly new at this, but are your rails straight or do they have a slight arc, bow or twist?

[jdonley]

The rails are straight and parallel.

[srwtlc]

John,

Check the Z axis for play front to back at various locations along the Y axis. Grab on to the bottom of the spindle and pull/push back and forth checking for play. If it's loose, you'll have to adjust the lower v-rollers to snug it up. Pay attention though to see if it is tight at one end of the Y axis and loose at the other end. My '07 machine had extremely out of parallel v-rails on the gantry and when the Z axis was adjusted at one end it was loose at the other. I had to make sure that the lower rail was parallel with the table first and then set the upper rail parallel with the lower one. Then after making sure that part was right, the Z axis lower v-rollers were adjusted.

[jdonley]

Thanks, Scott. I'll check that out tomorrow.